I2C IO Card for ESP-12E I2C Base Card

The I2C IO Card for ESP-12E I2C Base Card is another expander card for the ESP-12E I2C Base Card Project. This PCB is an address-selectable I2C module with two relays and six (6) GPIO pins, all driven from a single PCF8574 running at 3v. The relays are optically isolated, and generous mains isolation cutouts were provided to reduce the possibility of mains voltage tracking. A jumper to enable/disable the i2c pullup-resistors is also provided on the PCB.

The relays are powered from a single LDO regulator, accepting 12v DC from the 2x20pin female header on the bottom of the card. 3.3v and ground should also be applied to the card at the 2x20pin header.

It is worth mentioning that this circuit does not contain level converting circuitry and that the i2c bus thus runs at 3.3v to be compatible with ESP chips.

It is possible to use the card with other processors if the appropriate level converters are used on the i2c bus.

The Schematic

Manufacturing the PCB


Over the past eight years, PCBWay has continuously upgraded their MANUFACTURING plants and equipment to meet higher quality requirements, and now THEY also provide OEM services to build your products from ideas to mass production and access to the market.


The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5 USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

ATMega 328P Based PWM controller Card

As part of my recent ESP-12E I2C Base Board project, I designed an ATMega 328P Based PWM controller card, that can be used as an add-on card with the existing project, or standalone as a custom Arduino Nano compatible development board.

What is on the PCB?

The PWM controller card contains standard Arduino Nano circuitry running at 16MHz, without the USB to Serial converter, as well as a 3v to 5v level converter on the I2C port ( A4 and A5 ), as well as another 12v to 5v level converter, with a build in resistor-divider circuit, used to drive a 12v blower with 3.3v PWM control circuitry.

All analog inputs are broken out to make attaching additional sensors easier.

All the other unused GPIO pins are also broken out, either directly to headers on the PCB (D6~,D7,D8,D9~), D11,D12,D12 (ISCP Header) and D3 ( Marked RPM on the Fan Header)

Most of these pins are also additionally broken out onto the 2x20p female header at the bottom of the card ( See schematic for more details)

The board is designed to be powered from 12v DC (via the VIN pins on the 2x20p header) which is internally regulated down to 5v via an LDO voltage regulator.


External 3.3v should also be supplied to the 2x20Pin header to enable the I2C level converters on the same header. I2C is not directly broken out onto the PCB in this version of the PCB.

A reset button, and power led, as well as the standard led on D13 is also provided.

Manufacturing the PCB


Over the past eight years, PCBWay has continuously upgraded their MANUFACTURING plants and equipment to meet higher quality requirements, and now THEY also provide OEM services to build your products from ideas to mass production and access to the market.


The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5 USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

VC-01 and VC-02 Offline Voice Module

In a recent article, I took a look at the new VC-01 and VC-02 Voice offline voice modules from AI-Thinker. I mentioned that I was working on a very simple prototype PCB to do some more tests, as well as make practical use of the module in real life.

In this very short post, I will show off the initial prototype that I came up with.
While I have to admit that it is still in an extremely basic stage, It is already definitely useful.

Part of the reason for this is that there is not a lot of information available on the VC-01 and VC-02 at this stage, as well as the fact that more exotic features like I2C and SPI are still not accessible in the current firmware. I thus had to work with what was available, as well as take into consideration what will work with the standard factory firmware as well.

The prototype carrier PCB will thus only have two optically isolated relays and their supporting circuitry. I intend to actually use the PCB in my EE LAb area to control some of the lights in the area.

The Schematic

The schematic shows the relay control circuitry, comprising of my standard optic isolator-based relay driver, as well as headers to accept the VC-01 or VC-02 offline voice module kit PCB.

Testing the PCB

The PCB was tested using the standard factory firmware, as well as my custom firmware, kindly provided by AI-Thinker. Below is a short video of that in action. Please note that the relays was not yet connected to any external devices at this stage.

Manufacturing the PCB


Over the past eight years, PCBWay has continuously upgraded their MANUFACTURING plants and equipment to meet higher quality requirements, and now THEY also provide OEM services to build your products from ideas to mass production and access to the market.


The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5 USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

True OFFLINE Voice Assistant

Most of us are familiar with voice assistants these days; Google Assistant, Siri and Alexa are obviously the most well-known of these. They all share a common problem though: They are online, and can thus secretly record everything you say around them, for later use by their respective owners [ The Companies that created them ]. Having a true offline voice assistant can thus seem like the holy grail for privacy and security-minded people.

Introducing VC-01/VC-02

I was recently contacted by AI-Thinker and asked if I was interested to play with a new product of theirs, an offline voice module. I immediately jumped at the opportunity, as this was something that I wanted to get my hands on for a long time, providing it works of course…

AI-Thinker’s offline voice module is available in two models, the VC-01 and the VC-02.

My Sales Representative (Kat ) sent me both models, in a kit format, complete with speaker and microphone. The kit PCB also provides a USB port with a ch340 chip, as well as two push buttons (reset and wake-up) as well as 3 built-in LEDs ( White, Orange and Blue ).

These light up with the factory firmware, depending on what commands are issued to the device…

Let us take a look at how the factory firmware works; Thank you to Kat from Ai-Thinker for uploading the video, and sending the link to me 🙂

As we can see in the video above, the module seems to work very well… The question now arises if it can be customised to do what we want it to…

Custom Firmware – Do-able, but with a few caveats

Information in English on this module is very sparse. This is due to it being very new, and with AI-Thinker focusing most of their efforts for this module on the Chinese market for the time being. Which makes sense in one way, but also doesn’t in another.

After spending quite a bit of time trying to get information, my Sales Rep eventually gave me access to an online configuration utility, now be warned:
This is not for the faint of heart. The entire interface is in Chinese ( They are working on an English version, with time-to-completion between one (1) to four(4) weeks from starting the project. I can however not give any accurate dates at this stage, but was told that this development is underway).

Being no stranger to different languages, I thought to use google translate to translate the website. No, that didn’t work. Google refuses or the Chinese Website doesn’t allow it to? No answer as of yet. Any readers who do know any reasons for this, please comment below.

I was sort of successful in manually copy pasting line by line into google translate and got some translation back, but it was not very useful.

My next point to try was asking AI-Thinker to generate some firmware with the web tool. They gladly did that, and that works great. It is however not feasible in the long term to go that route every time.

This was possible because the AI-Thinker engineers, using the firmware development software, currently only available in Chinese, can set custom wake words and train voice commands with a 95% accuracy rate, before generating firmware and flashing it onto the respective module.


Write your own, someone will obviously say, and that was my next attempt. There is an API, and source code on GitHub, as well as Gitee ( The Chinese version of GitHub) The two sources are however not synced, and I was still not successful in getting anything useful from Gitee, once again due to a language issue, as well as the fact that some of the sources depend on 32bit dependencies for Ubuntu, whereas I am running a 64bit version… I did try it though, and can not report any success on that venture at all.

Once again, I will advice us all to wait for AI-Thinker to release an English version of the SDK and API for us all to use, which I am sure they will do at some stage in the near future.

See the video below of my custom firmware, once again demonstrated by Kat from AI-Thinker

Custom Firmware – Test 01

As we can see, it once again performs well, with a few issues, but quite acceptable…

Hardware access to the real world

As we have just seen in the video, there is also hardware access via pins, to the real world. There are however a few issues there as well…

Hardware pins are limited.
I2C and SPI, although advertised, are apparently not yet supported in any of the current firmware – Someone with information, please comment…

While there are 2 I2C interfaces, they can not be used at the same time
Information on the module

PCB Prototype – Of my own design

As a proof of concept, I have decided to design a quick prototype with relays to use as a more detailed test. I will update information on that soon…

My Conclusion

I definitely see potential here. This is a product which can be quite useful in the future, providing that the following is done:

Proper detailed documentation is provided in English as well as Chinese
API and SDK access is made available in English as well as Chinese
Firmware be updated to make all features available

Having said all of that, I do understand that development, and especially R&D do take a lot of time. Translating documents accurately does too.

I want to congratulate AI-Thinker on producing a very well-made unit, that will definitely bring the dream of a totally offline voice assistant a little bit closer to being a reality.

Voice recognition with my bastard South-African/British English Accent, heavily influenced by Afrikaans, went extremely well, even with the factory firmware.
I do thus not think anybody that can speak passable English will have a problem using the unit.


Robotic Toy Car – Part 5

In this almost post we look at the power distribution PCB for the almost completed Robotic Toy Car. I had many interesting issues to solve here, especially since I did not design my own Lipo battery charger circuit, but used a very useful little commercially available unit instead, the MH-CD42

Based on a relatively difficult chip to get information on, the module is basically an integrated Lipo charge/discharge module, with a built-in boost converter that provides 5v at a maximum of 2A current. What makes it special is the ability to simultaneously provide current and voltage, as well as charge the attached LiPo cell at the same time, when connected to an external charger.

It does, however, in my view at least, also have a few serious flaws, the most irritating of these being that it will completely discharge the attached LiPo cell even when completely switched off…

I have thus tried to stop this issue from occurring by adding a switch in line with the Lipo Cell, a quite obvious solution, but it should not have been needed if the chip functioned as intended… ( As far as I can gather, the module was originally designed to be used in USB power banks. This makes the flaw even more serious, as a self-discharging power bank really defeats the purpose)

Enough of that though, when it does work, it works great. just remember that you can not apply more than 5.5v DC to the charging input of the module.

The completed Power Distribution and charging module

The Schematic

There is actually not a lot going on here, as everything is already on the supplied module. I have just added a charging port, additional power headers for 5v output and ground, as well as direct access to the LiPo Cell output, and a switch header to cut off power to the MH-CD42 when it is not in use.

The PCB

The PCB was manufactured as a 2-layer FR-4 board. The entire top layer is used as a ground plane, and the bottom layer was used for the 5v and Vbat traces, which were made as big as possible to allow for the high current ( up to 2A ) that the unit can supply to a load.

The TOP later of the PCB is a complete ground plane.
The BOTTOM Layer caries only power traces for 5v and VBat
a 3D Render of the PCB, showing header pins and other connections

It is also worth mentioning that the VBAT pins are NOT 3.3v ( Remember that the LiPo cell can run from 4.2v down to 3.0v depending on the charge. These headers were only placed on the board to provide direct access to the LiPo cell, for use with for example an ADC input or for connection to a dev board that is already fitted with a buck converter or a suitable LDO voltage regulator.

The Actual PCB, as received from PCBWay
Top Layer of the PCB
Bottom Layer of PCB

Manufacturing the PCB


Over the past eight years, PCBWay has continuously upgraded their MANUFACTURING plants and equipment to meet higher quality requirements, and now THEY also provide OEM services to build your products from ideas to mass production and access to the market.

The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

Robotic Toy Car – Part 4

In this part of the series, Robotic Toy Car – Part 4, We will add some custom side-panels to the project. While the original toy did come with some laser cut aluminum side panels, I decided to replace them with PCB versions, with even more flashing lights (yes, this thing is turning into a “Christmas tree” , but that is what the eventual owner wanted… )

These side-panels will not be programmable. They will simply be operated from a standard 555 timer and a couple of other components, to give a flash time of about one second on and off each…

It is also an excellent project to showcase the capabilities of PCBWay, in dealing with a “rather difficult” PCB to manufacture. As you may know by now, I use PCBWay‘s services quite extensively, and I also only design my PCB’s with EasyEDA. EasyEDA is however quite limited in some aspects, and as far as myself, making panels of different designs on one PCB with complex shapes is not something that I do every day…

Let us take a look at what had to be done, and how well it was manufactured…

The PCB Layout

What we have here, is basically two mirrored side-panels ( as far as the visible “outside” is concerned anyway ) That consists of 6 led’s per side that will flash alternatively. On the “inside” we have a 555 timer chip, with some resistors and capacitors, as well as transistors that does the switching.

The Schematic

The difficulty of this PCB is definitely in the manufacturing. I was however pleasantly surprised with the excellent work that was done by PCBWay. Their Engineering staff did contact me early on in the order, with a suggested plan to manufacture, and once I approved that, they very quickly went on to production. My initial concern was that they suggested “mouse-bites” which we all know can sometimes come out a bit strange…

Completed PCB in packaging..

I was however extremely pleased when the above parcel arrived… They added side rails, and the “mouse-bytes” were super tiny.

After assembly ( not cleaned up yet )
After Assembly ( not cleaned up yet )
Installed on the toy car body

The “almost completed ” Robotic Toy Car

With the completion of the side-panels, it was also time to start work on the power wiring and other essential components of the project, which will get their own detailed post in a few days.

the “almost completed” project

Some details on the construction:
The toy originally came with a single 500mA 14500 cell, which unfortunately stopped working very soon after only a few uses… This was however one of the reasons why the entire project happened in the first place, so no complaints there.

I decided to replace it with a 18560 cell with a capacity of about 1900mA. This cell is much bigger however, and I had to think of where to place it. I decided to put it on the roof, sort of emulating a “spoiler”.

Some of the next parts of the project will be the remote control unit, which will basically be an ESP8266 running ESP-Now protocol, as well as a decent battery charging and power distribution circuit, that will protect the Lipo cell from over charging and discharging, as well as provide sufficient power for all the added electronics in the toy car.

“But you said it was Robotic, so why have a remote control?”

The initial plan for the project did indeed say robotic, but it is also designed to be a learning platform, especially to teach coding. With that in mind, it is definitely better to keep things simple for now, and add sensors and more capabilities later on, especially as I am actually planning to replace the main MCU board with a more powerful ESP32 in a next version anyway.

The car body is also extremely cramped, and does not have any space for mounting sensors at all. I plan to remedy that by designing and 3d-printing a whole new custom body shell later… providing that my young friend actually stays interested enough to learn the coding… If he doesn’t, he will as least have a very interesting looking custom remote controlled toy car.

Manufacturing the PCB

The PCB for this project is currently on its way from China, after having been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to be manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

Robot Toy Car – The Next steps

In our last project, we started working on repurposing an old toy car. In this part, Robot Toy Car – The next steps, we will take a look at the controller board for this project and discuss some of the problems that we have encountered up to now. Most of the various components for this project are still in the prototype stage, but It is quite important to get them tested to verify the final designs.

There are quite a few unique challenges in a project like this, which looks quite easy to solve but turn out to become quite challenging to get working just right in practice…

One of the most important, as well as the most frustrating part, turned out to be the H-Bridge Motor controller. The first prototype of this was introduced in the first part of this project. While functional on paper, as well as working quite well in real life, (when tested with an Arduino, as well as manually), It performs extremely poorly when used with the actual controller for this project, an ESP8266 12-E…

What could the reason be? How will I fix it…? The answers to that will be provided in a follow-up post. For now, let us take a look at the controller.

The unassembled ESP-8266 Controller board, straight from the factory
The Assembled ESP-8266 Controller board.

The Controller Board, details

Space inside the toy car is at a premium, so from the start, it was important to design a PCB that was small enough to fit, while also taking into consideration functionality, as well as all additional add-on components to ultimately be fitted to the project.

With this in mind, I have decided on the ESP-8266, which, while bigger than an Atmega328, does offer a few additional features, like WiFi, and ESP-Now, which will greatly help in controlling and even updating firmware OTA. The ESP-8266 does however also have a few serious flaws in this design, like limited useable GPIO pins, a 3.3v working voltage requirement, and quite high operating current requirements.

As the toy will likely not be used continuously, as well as the fact that it will run on batteries, which, can be replaced or recharged, I did not worry too much about the power issue. As far as the limited GPIO, that is where I2C comes in… It is quite easy to expand the GPIO with an IO Expander or two…

My main problem came in the form of the CH340G USB-to-UART converter chip. It seems like there must be quite a lot of counterfeit versions of these around, as none of the chips that I purchased, from many different suppliers, actually functioned, with the best one actually providing a USB port, but, when investigating with a logic analyser, the Rx and Tx lines of the UART, generating garbage…

Replacing it with a known working chip from a NodeMCU V1 board, magically solved the problem, verifying the PCB circuit as correct and working, and also proving that the purchased chips are definitely fake!

This was easily repaired by temporarily soldering jumper cables to the Rx and Tx lines on the ESP-8266, and using an external UART-to-USB converter to upload the initial sketch to the device. Future updates will be OTA, so not a problem in the long run anyway.

Controller Schematic

The controller schematic, above, is basically a rearranged stock NodeMCU v1 circuit, with the only difference being that only specific pins were broken out onto header pins. These will be used for controlling the two H-Bridges, and provide PWM as well as access to the I2C bus.

Software

Due to the fact that this controller is still definitely considered a prototype, my main focus is definitely on getting the control software sorted out first. That way, at least in my opinion, I can then focus on hardware issues responding to verified software inputs, without having to do both at the same time.

As mentioned before, I require OTA capability to upload new firmware to the device, so my starting point was the BasicOTA sketch provided with the Arduino IDE. This sketch was modified to perform some additional functionality, such as controlling the H-Bridges, PWM as well as a roof-mounted “status panel” with LED’s that also doubles as a visual display, to give a bit of colour to the project.

The “status panel” will be shown in a future post, however, with the only mention of it here being that it is I2C controlled, and based on a PCF8574.

The BasicOTA sketch is listed below.

#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>

#ifndef STASSID
#define STASSID "your-ssid"
#define STAPSK  "your-password"
#endif

const char* ssid = STASSID;
const char* password = STAPSK;

void setup() {
  Serial.begin(115200);
  Serial.println("Booting");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("Connection Failed! Rebooting...");
    delay(5000);
    ESP.restart();
  }

  // Port defaults to 8266
  // ArduinoOTA.setPort(8266);

  // Hostname defaults to esp8266-[ChipID]
  // ArduinoOTA.setHostname("myesp8266");

  // No authentication by default
  // ArduinoOTA.setPassword("admin");

  // Password can be set with it's md5 value as well
  // MD5(admin) = 21232f297a57a5a743894a0e4a801fc3
  // ArduinoOTA.setPasswordHash("21232f297a57a5a743894a0e4a801fc3");

  ArduinoOTA.onStart([]() {
    String type;
    if (ArduinoOTA.getCommand() == U_FLASH) {
      type = "sketch";
    } else { // U_FS
      type = "filesystem";
    }

    // NOTE: if updating FS this would be the place to unmount FS using FS.end()
    Serial.println("Start updating " + type);
  });
  ArduinoOTA.onEnd([]() {
    Serial.println("\nEnd");
  });
  ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {
    Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
  });
  ArduinoOTA.onError([](ota_error_t error) {
    Serial.printf("Error[%u]: ", error);
    if (error == OTA_AUTH_ERROR) {
      Serial.println("Auth Failed");
    } else if (error == OTA_BEGIN_ERROR) {
      Serial.println("Begin Failed");
    } else if (error == OTA_CONNECT_ERROR) {
      Serial.println("Connect Failed");
    } else if (error == OTA_RECEIVE_ERROR) {
      Serial.println("Receive Failed");
    } else if (error == OTA_END_ERROR) {
      Serial.println("End Failed");
    }
  });
  ArduinoOTA.begin();
  Serial.println("Ready");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  ArduinoOTA.handle();
}

Controlling the Toy Car Robot

Controlling the Toy Car is a complicated question, with many ideas jumping into my mind, only to be pushed aside by technical issues, as well as real-world constraints on what is physically possible to be mounted on the plastic body of the toy car, space available on the inside, as well as not interfering with suspensions, springs, turning wheels etc.

The chassis of the toy car

As is clearly visible, there is really not a lot of space available here for sensors. Mounting sensors to the body will also provide a bit of a challenge, as well as won’t really look nice either…

Give an old toy car new life

I have thus decided to implement remote control for the time being, and later, maybe after 3d-printing a more suitable body, to add sensors for autonomous functionality. The ESP-Now protocol will be used extensively for the remote control, as, in my opinion, it required no additional hardware, is quite fast, as well as being extremely easy to use. It does however make it necessary to use another ESP deice in the remote control unit.

Manufacturing the PCB

The PCB for this project is currently on its way from China, after having been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to be manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.

Give an old toy car new life…

Give an old toy car new life

Many of us have old toys laying around the house, they belong to our children or the children of our friends. In this article, I will attempt to show you how to give an old toy car new life, as well as hopefully teach a child a few interesting things with electronics.

The inspiration for this article comes from my friend’s 7-year-old boy, who, way too clever for his age, always has a lot of very interesting questions. His mother and I have thus decided to do an experiment:
“Let us try to teach him Arduino programming, so he can start to make his own toys”

Obviously, the challenges in this venture are many…
To name a few:
The boy speaks only Thai, so English is a no-go.
Soldering is out of the question, due to his age, as well as safety issues – All teaching will have to be done on a breadboard.

My challenges apart, this is a project that many people would want to attempt, so it is important to start with a bit of theory.

Controlling a DC Motor from a microcontroller

DC motors, like those found in toy cars, are inductive loads, and that means that they induce electromagnetic fields when switched on or off. These EMF fields can damage your sensitive microcontroller quite easily. Another thing to remember is that your typical microcontroller can only source or sink in the region of 25mA to 50mA of current, not quite enough to drive a motor, let alone a toy car.

Directional control of the motor

In our toy car, we would definitely want the driving motor to be able to change direction, meaning spin forwards or backwards, thereby changing the direction that the car is travelling. This is achieved by using a circuit called an H-Bridge. In this circuit, four transistors, either BJTs or MOSFETs are arranged in a particular way to allow us to change the direction that the motor spins by changing certain logic signals.

Implementing an H-Bridge with switches

In the picture above, we simulate the H-Bridge circuit using slide switches in order to explain the method of operation. It should be clear that the direction is changed by switching on diagonally opposite switches.

Driving a motor with a transistor

In the picture above, we implement a simple, one-directional motor control circuit using a single transistor. This circuit still has the limitation that the motor can only spin in a single direction.

Half of an H-Bridge

In the circuit above, we combine the two motor driver circuits (with PNP and NPN transistor ) to complete one half of the H-Bridge circuit. This circuit still has the limitation that we can only spin the motor in a single direction.

The completed H-Bridge circuit

In the picture above, we added another half H-Bridge to complete the circuit. We will thus have 2 PNP and 2 NPN transistors, which form the completed circuit. This circuit will give us full bi-directional control of the motor. We can also control the speed of the motor if we apply a suitable PWM signal to the bases of the NPN transistors – we do need to be careful of SHOOT THROUGH and shorts though.

My proposed Motor Driving Circuit

the inside of the toy car, without the old broken circuit-board

In the picture above, we can clearly see that there is not a lot going on inside this toy car. An On-Off switch is connected to the battery compartment, and two wires go to the drive- and steering motor.

Interfacing this car to a microcontroller is thus going to require two separate H-Bridge circuits. One for the drive motor, and the second for the steering.

Dual H-Bridge Circuit diagram

I have designed the circuit above to control both motors of the toy car, the control signals are simplified to 2 per H-Bridge, and a common PWM signal to control speed.

Manufacturing the PCB

The PCB for this project is currently on its way from China, after having been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to be manufactured.

PCBWay

If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.


Build your own USB-ASP Programmer Clone

Using more ATMEGA based MCU’s in my recent projects, and not using ready-made Arduino boards for any of them, it became necessary to invest in a dedicated ASP programmer to flash the MCU’s. Huge delays on electronics components, with confirmed orders being mysteriously cancelled due to sourcing issues, and the high cost of “original OEM ASP programmers”, send me on a search for a DIY style programmer, like the old “NOPPP” ( NO PARTS PIC Programmer) in the good old days…

Personal computers have changed a lot, and while ATMEGA chips are not PIC’s, I did feel that it could be done. Given the fact that you could also use an Arduino UNO as an ISP, and doing a little more digging, I finally found a very attractive alternative…

Thomas Fischl, on his website,https://www.fischl.de/usbasp, has an open-source hardware project, that seemed to be exactly what I needed. His device is capable of programming 5v devices, at various speeds, including a super slow one. He has also written firmware for the device, and although the last update was in 2011, It still seems to be working well, or at least as far as I can see…

I did however decide to add my own twist to the design and build in a logic level converter, to be able to program 3.3v devices as well…

The modified schematic is below:

Schematic Page 1
Schematic Page 2

I chose to do my own PCB layout, to incorporate the changes listed earlier, namely the logic level conversion from 5v to 3v, as well as adding a 3.3v LDO voltage regulator to provide 3.3v to the target in case it is required.

PCB Topside
PCB Bottom Side
3D Render of the PCB

The PCB is still in transit from the factory, and thus I will update this article later with pictures of the actual device.

Firmware can be flashed using any ASP programmer, Arduino as ISP as well, but with the caveat that you have to use AVRDude from the command line… More on that in the follow-up post… ( I would like to show actual screenshots of the process, and not theory.. ). The links to the firmware are available on https://www.fischl.de/usbasp, courtesy of Thomas Fischl, whom I would like to thank for making this open-source hardware project available freely, as well as for writing and maintaining the firmware.


The PCB can be ordered, or the design files downloaded ( a free download ) from my Projects page at PCBWay soon…

This PCB was manufactured at PCBWAY. The Gerber files and BOM, as well as all the schematics, will soon be available as a shared project on their website. If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.




Port Extender Card for the MCU-8266-12E

Port Extender Card for the MCU-8266-12E IoT Controller

Introduction

After quite a few experiments, and playing with a lot of ideas, we have finally produced and tested an almost final prototype for the MCU-8266-12E IoT Controller Port Extender Card. While the baseboard already has quite a lot of free GPIO pins for additional sensors and devices, It did however have quite a few issues, namely a lack of sufficient Power outputs, difficulty access to the I2C bus, as well as only 2 relay outputs. Granted that you do have access to unused pins on the PCF8574 Port Extender, We nonetheless decided that an add-on card would definitely make sense to allow this device to really be more useable.

While looking at various ideas for this card, the most flexible seemed to be the APE Protocol device as documented in ESPHome. They used a standard Arduino board for that, but we decided that, after testing it with an Arduino Nano, since it seems to work well, let us just design a dedicated PCB. It also looks much better as well 🙂

Some Features (Aside from being a fully functional Arduino clone as well)

1). Dedicated LDO Regulators for 5v and 3.3v (800mA each), with jumpers to switch them on or off (receive power only from the IoT Motherboard).
2.) Dedicated Logic Level Converter on the I2C Bus ( This is sort of very much needed 🙂 The Atmega 328P-AU is running at 5v on this device, to enable it to run at 16Mhz.. and the ESP8266 on the Motherboard is a 3.3v device..

There are also 3x 3.3V I2C Headers, complete with 3.3v and Ground, as well as a single 5v I2C header
3). 8 Analog Inputs ( While practically you can only use 6 of these if you use I2C )
4). Voltage Divider provided on A0 to measure VIN ( to be safe, we calculated the resistors for 22v)
5). 100R current limiting resistor on A1 and A2, to measure 5v and 3.3v as well…
Analog inputs A0, A1 and A2 can be switched back to normal operation by changing the jumper at J2,J3 or J4 from On to Off.
6). 12 Digital Inputs/Outputs (14 if you use D0 and D1 as well), as well as a Jumper to remove the LED on D13.
7). Full access to the PCF8574 and ESP8266 Pins from the motherboard below.

Pictures of the PCB

Circuit Diagram

ATMega328P-AU Circuit diagram with LDO Regulators, headers and supporting circuitry.
Analog measuring circuitry, level converters and supporting circuitry and headers

Uploading Code to the ATMega328P

Uploading code to the device requires the use of either an ISCP programmer ( Arduino as ISP works well ) or in the case of a pre-boot loaded chip, a USB-to-Serial converter. We did not find it necessary to add a dedicated USB-to-Serial converter onto the PCB. It is quite easy enough to do any flashing with the tools mentioned above.


Make sure that the PCB is not stacked when doing this. ( This will prevent excessive current use of other components when you supply 5v to the PE card.


Procedure to upload using ICSP

During assembly, you are required to solder a single 90-degree bend pin header on the bottom side of the PCB, in the same hole as the board side edge of the RESET push-button. This will serve as the RESET Pin for the ISCP. Other connections are as follows:

H2 Header <- > ICSP Programmer
MOSI (E11~) – MOSI ( or Pin 11 on Arduino as ISP )
MISO (E12 ) – MISO ( or Pin 12 on Arduino as ISP )
SCK (E13) – D13 (or Pin 13 on Arduino as ISP )
RESET – D10 (or Pin 10 on Arduino as ISP )

5v and Ground from Arduino as ISP or ISCP Programmer to any 5v and ground pin on the PE Card

Please note the description above for assembly of the RESET pin header



Procedure to upload using USB-to-Serial converter

H1 Header

E0/Rx <- to Tx of USB-to-Serial converter
E1/Tx -> to Rx of USB-to-Serial converter

H2 Header

DTR <-> to DTR of USB-to-Serial converter [ This connection is needed for successful uploading. Don’t leave it out ]


5v and Ground from the USB-to-Serial converter to any 5v and ground pin on the PE Card


Testing with ESPHome APE protocol and the MCU-8266-12E IoT controller

The following Arduino Sketch needs to be uploaded to the device.
It will allow the device to function as a custom I2C device. Feel free to change the I2C address in the sketch as you choose, but remember to use the same address in your ESPHome YAML configuration file

/*
Ports:
  0 0 .. 13 13
  A0: 14, A1: 15, A2: 16, A3: 17: A4: 18: A5: 19: A6: 20, A7: 21
  port bits: 5 ... 0..32
  0:   0: 00000
  1:   1: 00001
  A7: 21: 10101
*/

#include <Arduino.h>
#include <Wire.h>

//#define DEBUG // remove debug so pin 0 and 1 can be used for IO

#define I2C_ADDRESS 8

void onRequest();
void onReceive(int);

void setup()
{
#ifdef DEBUG
  Serial.begin(115200);
  Serial.println(F("Init "));
#endif

  analogReference(INTERNAL);

  Wire.begin(I2C_ADDRESS);
  Wire.onRequest(onRequest);
  Wire.onReceive(onReceive);

#ifdef DEBUG
  Serial.println(F("Wire ok"));
#endif
}

void loop()
{
  //int temp = analogRead(A1);
  //Serial.println(temp);
}

volatile byte buffer[3];
volatile byte len = 1;

#define DIGITAL_READ(b, pin, mask) \
  if (digitalRead(pin))            \
    buffer[b] |= mask;

void readDigital()
{
  len = 3;
  buffer[0] = 0;
  DIGITAL_READ(0, 0, 1);
  DIGITAL_READ(0, 1, 2);
  DIGITAL_READ(0, 2, 4);
  DIGITAL_READ(0, 3, 8);
  DIGITAL_READ(0, 4, 16);
  DIGITAL_READ(0, 5, 32);
  DIGITAL_READ(0, 6, 64);
  DIGITAL_READ(0, 7, 128);

  buffer[1] = 0;
  DIGITAL_READ(1, 8, 1);
  DIGITAL_READ(1, 9, 2);
  DIGITAL_READ(1, 10, 4);
  DIGITAL_READ(1, 11, 8);
  DIGITAL_READ(1, 12, 16);
  DIGITAL_READ(1, 13, 32);
  DIGITAL_READ(1, A0, 64);
  DIGITAL_READ(1, A1, 128);

  buffer[2] = 0;
  DIGITAL_READ(2, A2, 1);
  DIGITAL_READ(2, A3, 2);

// I2C
//DIGITAL_READ(2, A4, 4);
//DIGITAL_READ(2, A5, 8);

// DIGITAL READ not supports on A3 .. A7
#ifdef DEBUG_READ
  Serial.print(F("Read 3 bytes: "));
  Serial.print(buffer[0]);
  Serial.print(' ');
  Serial.print(buffer[1]);
  Serial.print(' ');
  Serial.println(buffer[2]);

#endif
}
void readAnalog(int pin)
{
  int val = analogRead(A0 + pin);
  len = 2;
  buffer[0] = val & 0xFF;
  buffer[1] = (val >> 8) & 0b11;
#ifdef DEBUG_READ
  Serial.print(F("Read analog pin "));
  Serial.println(pin);
#endif
}

void onRequest()
{
  Wire.write(const_cast<uint8_t *>(buffer), len);
}

#define CMD_DIGITAL_READ 0x0

#define CMD_WRITE_ANALOG 0x2
#define CMD_WRITE_DIGITAL_HIGH 0x3
#define CMD_WRITE_DIGITAL_LOW 0x4

#define CMD_SETUP_PIN_OUTPUT 0x5
#define CMD_SETUP_PIN_INPUT_PULLUP 0x6
#define CMD_SETUP_PIN_INPUT 0x7

// 8 analog registers.. A0 to A7
// A4 and A5 not supported due to I2C
#define CMD_ANALOG_READ_A0 0b1000 // 0x8
// ....
#define CMD_ANALOG_READ_A7 0b1111 // 0xF

#define CMD_SETUP_ANALOG_INTERNAL 0x10
#define CMD_SETUP_ANALOG_DEFAULT 0x11

void onReceive(int numBytes)
{
#ifdef DEBUG_READ
  Serial.print("Received bytes: ");
  Serial.println(numBytes);
#endif
  int cmd = Wire.read();

  switch (cmd)
  {
  case CMD_DIGITAL_READ:
    readDigital();
    break;
  }

  if (cmd >= CMD_ANALOG_READ_A0 && cmd <= CMD_ANALOG_READ_A7)
  {
    readAnalog(cmd & 0b111);
    return;
  }

  int pin = Wire.read();

  switch (cmd)
  {
  case CMD_WRITE_DIGITAL_HIGH:
  case CMD_WRITE_DIGITAL_LOW:
  {
    bool output = cmd == CMD_WRITE_DIGITAL_HIGH;
    digitalWrite(pin, output);
#ifdef DEBUG
    Serial.print(F("Pin "));
    Serial.print(pin);
    Serial.println(output ? F(" HIGH") : F(" LOW"));
#endif
    break;
  }
  case CMD_WRITE_ANALOG:
  {
    int val = Wire.read() & (Wire.read() << 8);
    analogWrite(pin, val);
#ifdef DEBUG
    Serial.print(F("Pin "));
    Serial.print(pin);
    Serial.print(F(" Analog write "));
    Serial.println(val);
#endif
    break;
  }
  case CMD_SETUP_PIN_OUTPUT:
    pinMode(pin, OUTPUT);
#ifdef DEBUG
    Serial.print(F("Pin "));
    Serial.print(pin);
    Serial.println(F(" OUTPUT"));
#endif
    break;
  case CMD_SETUP_PIN_INPUT:
    pinMode(pin, INPUT);
#ifdef DEBUG
    Serial.print(F("Pin "));
    Serial.print(pin);
    Serial.println(F("INPUT"));
#endif
    break;
  case CMD_SETUP_PIN_INPUT_PULLUP:
    pinMode(pin, INPUT_PULLUP);
#ifdef DEBUG
    Serial.print(F("Pin "));
    Serial.print(pin);
    Serial.println(F("INPUT PULLUP"));
#endif
    break;
  case CMD_SETUP_ANALOG_INTERNAL:
    analogReference(INTERNAL);
#ifdef DEBUG
    Serial.println(F("Analog reference INTERNAL"));
#endif
    break;
  case CMD_SETUP_ANALOG_DEFAULT:
    analogReference(DEFAULT);
#ifdef DEBUG
    Serial.println(F("Analog reference DEFAULT"));
#endif
    break;
  }
}

The following C header file needs to be uploaded to your Home Assistant ESPHome folder.

// Must disable logging if using logging in main.cpp or in other custom components for the
//  __c causes a section type conflict with __c thingy
// you can enable logging and use it if you enable this in logger:
/*
logger:
  level: DEBUG
  esp8266_store_log_strings_in_flash: False
  */

//#define APE_LOGGING

// take advantage of LOG_ defines to decide which code to include
#ifdef LOG_BINARY_OUTPUT
#define APE_BINARY_OUTPUT
#endif
#ifdef LOG_BINARY_SENSOR
#define APE_BINARY_SENSOR
#endif
#ifdef LOG_SENSOR
#define APE_SENSOR
#endif

static const char *TAGape = "ape";

#define APE_CMD_DIGITAL_READ 0
#define APE_CMD_WRITE_ANALOG 2
#define APE_CMD_WRITE_DIGITAL_HIGH 3
#define APE_CMD_WRITE_DIGITAL_LOW 4
#define APE_CMD_SETUP_PIN_OUTPUT 5
#define APE_CMD_SETUP_PIN_INPUT_PULLUP 6
#define APE_CMD_SETUP_PIN_INPUT 7
// 8 analog registers.. A0 to A7
// A4 and A5 not supported due to I2C
#define CMD_ANALOG_READ_A0 0b1000 // 0x8
// ....
#define CMD_ANALOG_READ_A7 0b1111 // 0xF

#define CMD_SETUP_ANALOG_INTERNAL 0x10
#define CMD_SETUP_ANALOG_DEFAULT 0x11

#define get_ape(constructor) static_cast<ArduinoPortExpander *>(constructor.get_component(0))

#define ape_binary_output(ape, pin) get_ape(ape)->get_binary_output(pin)
#define ape_binary_sensor(ape, pin) get_ape(ape)->get_binary_sensor(pin)
#define ape_analog_input(ape, pin) get_ape(ape)->get_analog_input(pin)

class ArduinoPortExpander;

using namespace esphome;

#ifdef APE_BINARY_OUTPUT
class ApeBinaryOutput : public output::BinaryOutput
{
public:
  ApeBinaryOutput(ArduinoPortExpander *parent, uint8_t pin)
  {
    this->parent_ = parent;
    this->pin_ = pin;
  }
  void write_state(bool state) override;
  uint8_t get_pin() { return this->pin_; }

protected:
  ArduinoPortExpander *parent_;
  uint8_t pin_;
  // Pins are setup as output after the state is written, Arduino has no open drain outputs, after setting an output it will either sink or source thus activating outputs writen to false during a flick.
  bool setup_{true};
  bool state_{false};

  friend class ArduinoPortExpander;
};
#endif

#ifdef APE_BINARY_SENSOR
class ApeBinarySensor : public binary_sensor::BinarySensor
{
public:
  ApeBinarySensor(ArduinoPortExpander *parent, uint8_t pin)
  {
    this->pin_ = pin;
  }
  uint8_t get_pin() { return this->pin_; }

protected:
  uint8_t pin_;
};
#endif

#ifdef APE_SENSOR
class ApeAnalogInput : public sensor::Sensor
{
public:
  ApeAnalogInput(ArduinoPortExpander *parent, uint8_t pin)
  {
    this->pin_ = pin;
  }
  uint8_t get_pin() { return this->pin_; }

protected:
  uint8_t pin_;
};
#endif

class ArduinoPortExpander : public Component, public I2CDevice
{
public:
  ArduinoPortExpander(I2CBus *bus, uint8_t address, bool vref_default = false)
  {
    set_i2c_address(address);
    set_i2c_bus(bus);
    this->vref_default_ = vref_default;
  }
  void setup() override
  {
#ifdef APE_LOGGING
    ESP_LOGCONFIG(TAGape, "Setting up ArduinoPortExpander at %#02x ...", address_);
#endif

    /* We cannot setup as usual as arduino boots later than esp8266
            Poll i2c bus for our Arduino for a n seconds instead of failing fast,
            also this is important as pin setup (INPUT_PULLUP, OUTPUT it's done once)
        */
    this->configure_timeout_ = millis() + 5000;
  }
  void loop() override
  {
    if (millis() < this->configure_timeout_)
    {
      bool try_configure = millis() % 100 > 50;
      if (try_configure == this->configure_)
        return;
      this->configure_ = try_configure;

      if (ERROR_OK == this->read_register(APE_CMD_DIGITAL_READ, const_cast<uint8_t *>(this->read_buffer_), 3))
      {
#ifdef APE_LOGGING
        ESP_LOGCONFIG(TAGape, "ArduinoPortExpander found at %#02x", address_);
#endif
        delay(10);
        if (this->vref_default_)
        {
          this->write_register(CMD_SETUP_ANALOG_DEFAULT, nullptr, 0); // 0: unused
        }

        // Config success
        this->configure_timeout_ = 0;
        this->status_clear_error();
#ifdef APE_BINARY_SENSOR
        for (ApeBinarySensor *pin : this->input_pins_)
        {
          App.feed_wdt();
          uint8_t pinNo = pin->get_pin();
#ifdef APE_LOGGING
          ESP_LOGCONFIG(TAGape, "Setup input pin %d", pinNo);
#endif
          this->write_register(APE_CMD_SETUP_PIN_INPUT_PULLUP, &pinNo, 1);
          delay(20);
        }
#endif
#ifdef APE_BINARY_OUTPUT
        for (ApeBinaryOutput *output : this->output_pins_)
        {
          if (!output->setup_)
          { // this output has a valid value already
            this->write_state(output->pin_, output->state_, true);
            App.feed_wdt();
            delay(20);
          }
        }
#endif
#ifdef APE_SENSOR
        for (ApeAnalogInput *sensor : this->analog_pins_)
        {
          App.feed_wdt();
          uint8_t pinNo = sensor->get_pin();
#ifdef APE_LOGGING
          ESP_LOGCONFIG(TAGape, "Setup analog input pin %d", pinNo);
#endif
          this->write_register(APE_CMD_SETUP_PIN_INPUT, &pinNo, 1);
          delay(20);
        }
#endif
        return;
      }
      // Still not answering
      return;
    }
    if (this->configure_timeout_ != 0 && millis() > this->configure_timeout_)
    {
#ifdef APE_LOGGING
      ESP_LOGE(TAGape, "ArduinoPortExpander NOT found at %#02x", address_);
#endif
      this->mark_failed();
      return;
    }

#ifdef APE_BINARY_SENSOR
    if (ERROR_OK != this->read_register(APE_CMD_DIGITAL_READ, const_cast<uint8_t *>(this->read_buffer_), 3))
    {
#ifdef APE_LOGGING
      ESP_LOGE(TAGape, "Error reading. Reconfiguring pending.");
#endif
      this->status_set_error();
      this->configure_timeout_ = millis() + 5000;
      return;
    }
    for (ApeBinarySensor *pin : this->input_pins_)
    {
      uint8_t pinNo = pin->get_pin();

      uint8_t bit = pinNo % 8;
      uint8_t value = pinNo < 8 ? this->read_buffer_[0] : pinNo < 16 ? this->read_buffer_[1] : this->read_buffer_[2];
      bool ret = value & (1 << bit);
      if (this->initial_state_)
        pin->publish_initial_state(ret);
      else
        pin->publish_state(ret);
    }
#endif
#ifdef APE_SENSOR
    for (ApeAnalogInput *pin : this->analog_pins_)
    {
      uint8_t pinNo = pin->get_pin();
      pin->publish_state(analogRead(pinNo));
    }
#endif
    this->initial_state_ = false;
  }

#ifdef APE_SENSOR
  uint16_t analogRead(uint8_t pin)
  {
    bool ok = (ERROR_OK == this->read_register((uint8_t)(CMD_ANALOG_READ_A0 + pin), const_cast<uint8_t *>(this->read_buffer_), 2));
#ifdef APE_LOGGING
    ESP_LOGVV(TAGape, "analog read pin: %d ok: %d byte0: %d byte1: %d", pin, ok, this->read_buffer_[0], this->read_buffer_[1]);
#endif
    uint16_t value = this->read_buffer_[0] | ((uint16_t)this->read_buffer_[1] << 8);
    return value;
  }
#endif

#ifdef APE_BINARY_OUTPUT
  output::BinaryOutput *get_binary_output(uint8_t pin)
  {
    ApeBinaryOutput *output = new ApeBinaryOutput(this, pin);
    output_pins_.push_back(output);
    return output;
  }
#endif
#ifdef APE_BINARY_SENSOR
  binary_sensor::BinarySensor *get_binary_sensor(uint8_t pin)
  {
    ApeBinarySensor *binarySensor = new ApeBinarySensor(this, pin);
    input_pins_.push_back(binarySensor);
    return binarySensor;
  }
#endif
#ifdef APE_SENSOR
  sensor::Sensor *get_analog_input(uint8_t pin)
  {
    ApeAnalogInput *input = new ApeAnalogInput(this, pin);
    analog_pins_.push_back(input);
    return input;
  }
#endif
  void write_state(uint8_t pin, bool state, bool setup = false)
  {
    if (this->configure_timeout_ != 0)
      return;
#ifdef APE_LOGGING
    ESP_LOGD(TAGape, "Writing %d to pin %d", state, pin);
#endif
    this->write_register(state ? APE_CMD_WRITE_DIGITAL_HIGH : APE_CMD_WRITE_DIGITAL_LOW, &pin, 1);
    if (setup)
    {
      App.feed_wdt();
      delay(20);
#ifdef APE_LOGGING
      ESP_LOGI(TAGape, "Setup output pin %d", pin);
#endif
      this->write_register(APE_CMD_SETUP_PIN_OUTPUT, &pin, 1);
    }
  }

protected:
  bool configure_{true};
  bool initial_state_{true};
  uint8_t read_buffer_[3]{0, 0, 0};
  unsigned long configure_timeout_{5000};
  bool vref_default_{false};

#ifdef APE_BINARY_OUTPUT
  std::vector<ApeBinaryOutput *> output_pins_;
#endif
#ifdef APE_BINARY_SENSOR
  std::vector<ApeBinarySensor *> input_pins_;
#endif
#ifdef APE_SENSOR
  std::vector<ApeAnalogInput *> analog_pins_;
#endif
};

#ifdef APE_BINARY_OUTPUT
void ApeBinaryOutput::write_state(bool state)
{
  this->state_ = state;
  this->parent_->write_state(this->pin_, state, this->setup_);
  this->setup_ = false;
}
#endif

The file should be named “arduino_port_expander.h”

Make the following changes to your ESPHome YAML configuration file for the MCU-8266-12E device

esphome:
  name: mcu-8266-12e-01
  platform: ESP8266
  board: nodemcuv2
  includes:
      - arduino_port_expander.h
# Note the include file - This loads the APE Header

# Enable logging
logger:

# Enable Home Assistant API
api:

ota:
  password: "<your password will be different - dont change it>"

wifi:
  ssid: <your ssid>
  password: <your password>

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "MCU-8266-Hotspot"
    password: "password"

captive_portal:

i2c:
# PCB Prototype
  sda: GPIO5
  scl: GPIO4
# PCB Rev 1.5 or higher, comment the above 2 lines
# and uncomment
#sda: GPIO4
#scl: GPIO5
#################### - IMPORTANT ###########
  scan: true
  id: i2c_bus_a
  
pcf8574:
  - id: 'pcf8574_hub'
    address: 0x22 # Set at 0x22, feel free to change to your liking, Remember to set the chip to the address you choose as well
    pcf8575: false

time:
  - platform: sntp
    id: ha_time
    timezone: "Etc/GMT+7"

status_led:
  pin:
    number: GPIO16
    inverted: true

#Define the APE as a custom component, taking care to ensure that:
#1). The I2C Bust ID is the same as the one you have defined in the I2C: Section
#2). The address of the APE is the same as the one you set in the sketch
    
custom_component:
  - id: ape
    lambda: |-
      auto ape_component = new ArduinoPortExpander(i2c_bus_a, 0x08,true);
      return {ape_component};
    

sensor:

  - platform: custom
    lambda: |-
      return {ape_analog_input(ape, 0),  // 1 = A1
             ape_analog_input(ape, 1),
             ape_analog_input(ape, 2)};
   
#We define 3 analog inputs (A0,A1,A2) to monitor voltages on the card
#Note that you MUST define them in the sensors section below as well AND
#THAT THEY MUST BE IN THE SAME SEQUENCE THAT YOU DEFINED THEM IN ABOVE HERE
#
#ALSO NOTE THAT YOU CAN "NOT" use A4 and A5, as they are used for I2C !
#
# As an example, of adding another 3 analog inputs, your definition above will change to:
#
#    return {ape_analog_input(ape, 0),
#           ape_analog_input(ape, 1),
#           ape_analog_input(ape, 2),
#           ape_analog_input(ape, 3),
#           ape_analog_input(ape, 6),
#           ape_analog_input(ape, 7)};
#
#
# Now define the sensors connected to these analogs below:

             
    sensors:
      - name: "PE Card VIN"
        id: analog_a0
        device_class: "voltage"
        unit_of_measurement: "v"
        accuracy_decimals: 2
        filters:
          - lambda: return x * (22.00/1023.0);
          - throttle: 60s

# We use a lambda to scale the value of VIN - Our Voltage divider was designed around 22 volt
# thus we need 22 volt here in the calculation as well to make it accurate
#
      - name: "PE Card 5v"
        id: analog_a1
        device_class: "voltage"
        unit_of_measurement: "v"
        accuracy_decimals: 2
        filters:
          - lambda: return x * (5.02/1023.0); 
          - throttle: 60s
      - name: "PE Card 3v"
        id: analog_a2
        device_class: "voltage"
        unit_of_measurement: "v"
        accuracy_decimals: 2
        filters:
          - lambda: return x * (5.02/1023.0);
          - throttle: 60s
 
# The ATMega328P 's Analog Reference is set to 5v internally, thus we need to also scale the 
# 3v input with a maximum of 5v ... 

# In case you enabled the other 3 Analog Inputs above, you need to add the following
#
#    - name: "Analog 3"
#      id: analog_a3
#      filters:
#        - throttle: 60s
#    - name: "Analog 6"
#      id: analog_a6
#      filters:
#        - throttle: 60s
#    - name: "Analog 7"
#      id: analog_a7
#      filters:
#        - throttle: 60s
#
#
             
             
             
  - platform: adc
    pin: VCC
    name: "ESP8266 Chip Voltage"
    id: mcu_voltage
    unit_of_measurement: "V"
    device_class: "voltage"
    accuracy_decimals: 2
    update_interval: 60s
    
  - platform: wifi_signal
    name: "WiFi Signal Sensor"
    id: wifi_strength
    device_class: "signal_strength"
    unit_of_measurement: "dBm"
    update_interval: 240s
    

#Digital outputs function the same

output:
- platform: custom
  type: binary
  lambda: |-
    return {ape_binary_output(ape, 2),
            ape_binary_output(ape, 3),
            ape_binary_output(ape, 4),
            ape_binary_output(ape, 5),
            ape_binary_output(ape, 6),
            ape_binary_output(ape, 7)};
  outputs:
    - id: ape_output_p2
      inverted: false
    - id: ape_output_p3
      inverted: false
    - id: ape_output_p4
      inverted: false
    - id: ape_output_p5
      inverted: false
    - id: ape_output_p6
      inverted: false
    - id: ape_output_p7
      inverted: false
      
- platform: gpio
  id: relay_1
  pin:
    pcf8574: pcf8574_hub
    number: 0
    mode: OUTPUT
    inverted: true
- platform: gpio
  id: relay_2
  pin:
    pcf8574: pcf8574_hub
    number: 1
    mode: OUTPUT
    inverted: true
- platform: gpio
  id: led_status_1
  pin:
    pcf8574: pcf8574_hub
    number: 2
    mode: OUTPUT
    inverted: true
- platform: gpio
  id: led_status_2
  pin:
    pcf8574: pcf8574_hub
    number: 3
    mode: OUTPUT
    inverted: true
      
binary_sensor:
  - platform: gpio
    id: push_button_1
    name: 'Relay1 Pushbutton'
    device_class: ''
    pin: 
      pcf8574: pcf8574_hub
      number: 4
      mode: INPUT
      inverted: true
    on_press:
      then:
        - switch.toggle: switch_relay1
        
  - platform: gpio
    id: push_button_2
    name: 'Relay2 Pushbutton'
    device_class: ''
    pin:
      pcf8574: pcf8574_hub
      number: 5
      mode: INPUT
      inverted: true
    on_press:
      #min_length: 50ms
      #max_length: 500ms
      then:
        - switch.toggle: switch_relay2
    filters:
        - delayed_on_off: 50ms
      
  

switch:
  - platform: output
    id: switch_relay1
    name: "Relay No. 1 (#0)"
    output: relay_1
    on_turn_on:
      - output.turn_on: led_status_1
    on_turn_off:
      - output.turn_off: led_status_1
      
  - platform: output
    id: switch_relay2
    name: "Relay No. 2 (#1)"
    output: relay_2
    on_turn_on:
      - output.turn_on: led_status_2
    on_turn_off:
      - output.turn_off: led_status_2
  - platform: restart
    id: reboot_switch
    name: "Reboot Me"

Detailed information on the APE is available here

Manufacturing the PCB

This PCB was manufactured at PCBWAY. The Gerber files and BOM, as well as all the schematics, will soon be available as a shared project on their website. If you would like to have PCBWAY manufacture one of your own, designs, or even this particular PCB, you need to do the following…
1) Click on this link
2) Create an account if you have not already got one of your own.
If you use the link above, you will also instantly receive a $5USD coupon, which you can use on your first or any other order later. (Disclaimer: I will earn a small referral fee from PCBWay. This referral fee will not affect the cost of your order, nor will you pay any part thereof.)
3) Once you have gone to their website, and created an account, or login with your existing account,

4) Click on PCB Instant Quote

5) If you do not have any very special requirements for your PCB, click on Quick-order PCB

6) Click on Add Gerber File, and select your Gerber file(s) from your computer. Most of your PCB details will now be automatically selected, leaving you to only select the solder mask and silk-screen colour, as well as to remove the order number or not. You can of course fine-tune everything exactly as you want as well.

7) You can also select whether you want an SMD stencil, or have the board assembled after manufacturing. Please note that the assembly service, as well as the cost of your components, ARE NOT included in the initial quoted price. ( The quote will update depending on what options you select ).

8) When you are happy with the options that you have selected, you can click on the Save to Cart Button. From here on, you can go to the top of the screen, click on Cart, make any payment(s) or use any coupons that you have in your account.

Then just sit back and wait for your new PCB to be delivered to your door via the shipping company that you have selected during checkout.