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.

Special Limited Offer – Get your PCB for only $1

PCB for only $1

Every once in a while, we get an opportunity to take advantage of an exceptional deal. Recently, the friendly people at PCBPartner.com reached out to me with another great deal… “Get your next PCB for only $1!”

You will get the following:
10 FR-4 PCB, 1 or 2 layers, with Green Soldermask, in dimensions not exceeding 100mmx100mm, Manufactured and delivered to your door for only 1 (one) $USD.
This promotion will be valid until 31 May 2022, with AIRMAIL shipping included.

Promotion from PCBPartner

Who is PCBPartner.com

PCBPartner.com is owned and operated by Kinji Group, established in 1997. We have over 20 years of experience in PCB manufacturing, PCB design, component manufacturing and distribution, PCB assembly and PCB CAD software development.

While Kinji Group has 3 PCB factories in China, we have also developed strategic partnerships with more than 15 other factories around Asia. We, therefore, have a large group of specialists in PCB manufacturing, quality control, technical support and part sourcing to support your innovative ideas and products.

Our over 500 employees are spread across 8 branches in Mainland China (Shenzhen, Dongguan, Shanghai, Wuxi, Chengdu, Xiamen), Hong Kong SAR, and Taiwan. And we’re still growing!

Why Should you use PCBPartner for your next PCB order?

Variety of PCB Material

Up to 54 layers during PCB manufacturing.

FR-4 with different tg (135,150,170),
CTI 600 (Halogen free) PCB material,
Aluminium base PCB,
Flexible PCB,
Rigid-Flexible PCB,
Rogers, and many more materials.
Whatever material you need, they can deliver.

Special PCB Specifications:

Regular PCB production for these special PCB specifications

● Impedance control

● Custom-layer stack up

● 1-3 oz copper thickness for outer/inner layers

● Hard gold, ENEPIG, OSP surface finish

● Two different solder mask colours on one PCB

● Edge connector plating

● Edge plating

● Via filled with aluminium/resin

● And more…

Fast Lead Time

Turnaround is quick as prototypes usually take as little as 24 hours to produce, with a direct pickup service from their warehouse. They partner with DHL and FedEx for this to make sure you get your PCB in the shortest time possible. They also offer express production options for small and medium-sized batches so that you get your boards EVEN quicker.

Competitive Pricing

Get competitive pricing on prototypes and your future mass production. For any mass production orders, contact them so that they can find the best pricing and shipping solutions to maintain your competitiveness

Ordering boards in bulk? Save more the larger your order:

US$10 off orders of 100+

US$10 off orders of 100+

US$50 off orders of 500+

US$120 off orders of 1000+

Quality Control

After 20 years, they have built a strict standard of quality – their quality control teams ensure all PCBs pass the AOI and E-test with 100%.

Technical Support

They have an experienced PCB manufacturing and engineering team to help you detect potential mistakes in your Gerber files. They also use – and have used for 15+ years – a reliable PCB testing software solution, iPCB, to detect mistakes in designs.

Excellent Customer Service Team

They have a passionate (and patient!) customer service team to help you solve any problems while ordering, handle engineering questions, or answer any after-sales service request. They will respond to you within 1 working day, that’s their customer service guarantee.

Flexible Payment Term

If you have a large amount of PCB to order every month and want to work with them for AMS 30 payment, they will be happy to sign an agreement with you.

Promotion from PCBPartner

ATMega328P prototype add-on card for use with the MCU-8266-12E IoT controller.

In August of 2021, MakerIoT2020 released the MCU-8266-12E IoT Controller PCB, (part 1 is available here in case you missed that). Shortly after that, we started working on an expansion add-on card, that would work with the APE (Arduino Port Expander) protocol in ESPHome.

While I could have used a standard Arduino board for this, and in fact, I have done so during many of the testing stages,
I decided to design a custom PCB specifically for this task, in order to achieve two specific things…

1). The standard Arduino Board comes in either a 5v logic or 3v logic device. While this is perfect for many projects,
it is still sometimes required to use a logic level converter with some sensors and devices. LORA is a good example of that. As I really dislike using a breadboard, due to their inherent unreliable connections and the ever-present mess of wires going everywhere, I wanted an Arduino or ATMEGA328 based device that already has a level converter built-in.

As I could not find anything like that for sale, I decided to build my own, as you will see shortly.

2). I wanted to start moving away from using the Arduino IDE as much as possible. While the Arduino IDE is great for most tasks, It does lack in a few areas. I thus want to slowly ease myself back into using AVR C, and that requires a board that can be flashed via ICSP. ( yes, yes, you can flash an Arduino with ICSP as well. ) In the case of the planned expansion card, it would basically be a device that is flashed once and then left alone. Serial flashing would be quite unnecessary on there anyway.

The other reason, still part of point 2, is that it seems like everyone else is having all sorts of problems with fuses on the ATMega328 on custom boards etc… I wanted to see if that is really the case or not…

The PCB should also be useable as a standard “Arduino” type device to assist in prototyping and development.

ATMega328P Custom PCB – as a prototype add-on card to the MCU-8266-12E IoT controller

a Quick description of the PCB:

Standard Arduino type headers and pins are provided, with pin labels as for the Arduino Nano.
This gives us:

ATMega 328P MCU running at 16Mhz
12 Digital IO (D2 to D13) [ 14 if we use D1 and D2 as well ]
8 Analog Inputs (A0 to A7) [ A4 and A5 are used for I2C ]
ICSP header for uploading code
USB Port with CH340G for Arduino style serial flashing [This will be removed on the next version]
A Dedicated LDO 3.3v Voltage regulator, with a selectable input source (5v from USB, or directly from VIN – for high current use applications – MAX of 800mA)

An 8 Channel Bi-Directional Logic Level Converter, for now, the converter is fixed at bi-directional 3v to 5v conversion.
Additional 5v (x4), 3v (x4) and Ground pins (x8), as well as 2 general use bus connections (G1, G2) which I added for use with I2C

Led’s are provided on 5v, 3v, Serial Rx, Tx, as well as on pin D13.

Dimensions: 86mm x 51mm

Assembly – During Reflow on a hotplate.
During Reflow

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.

Conclusion

In conclusion, the PCB works quite well, with no issues with flashing the ATMEGA328P with an ICSP programmer from the Arduino IDE, as well as via USB from the Arduino IDE.

The level converter works as expected, successfully translating bidirectional signals on I2C and SPI to and from 3v and 5v devices.

In the next stage, we will focus on the stock APE protocol sketch, as provided by ESPHome, and then, once that is working perfectly, modify it to suit our needs.