I run a robotics club in a school, for students aged 11 – 14. We generally use a Raspberry Pi for the brains in our robots, but by the time you've added on motor controllers, voltage converters, wireless controllers etc... to the price of the Pi – It all starts to get rather expensive!

I wanted to make an all in one simple robotics controller, that was cheap enough to give to each of the students to keep, so once they had built their robots they could take them home to continue tinkering.

Here are the features I wanted to include on the board:

1. Dual H-Bridge – to drive 2 DC cheap TT motors, so nothing too fancy.

2. DC/DC converter – with an input voltage range of 6-12V, so you can use different types of batteries.

3. Reverse polarity protection – the students are definitely going to plug the battery in the wrong way around!

4.Enough spare input/output pins to drive a few servos or read a few sensors etc...

5. A micro controller with built in wireless communication. Preferably programmable in Micro/Circuit Python. Controllable from a mobile phone or website, so you don't need a physical controller to get started. But also with bluetooth, to connect to Playstation controllers, as we already use these for our other robots.

6. Cheap!

Nice, but not essential:

7. Through hole components – I want the students to assemble the boards themselves, so they can learn to solder, and have a better understanding of what the different parts on the board do.

8. Raspberry Pi Zero sized – so it can replace the PI Zero's in our existing robots.

This project was started back in 2022 when electronic components were still hard to get hold of. So I looked around in my parts box so see if there was anything I could use and believe it or not, I found a load of dual H-bridge modules, DC-DC converters and micro controllers.

Having a quick check on AliExpress I got an idea of the costs:

2 x Yellow TT motors = $2.00

DC/DC Converter = $0.45

Dual H-Bridge Module = $0.50

MOSFET = $0.45

ESP32 = $3.00

PCB = $0.40

Screw Terminals = $0.10

Header Pins = $0.10

6 x AA Battery holder (not including batteries) = $1.00

Total components = $8.00

These are of course subject to change but It's a good starting point.

This leaves $2.00 for materials for laser cutting or 3D printing to make a chassis – I think this is possible!