Tethered Mini Sumo robots are a great "Tech Ed" project for high school age students. But what if you could remove the tether? And keep the project under $20CAD?

That was the challenge that a high school teacher in Vancouver, BC, laid out for me... and the PiWiBot One is the answer. It uses through-hole components so that novices can learn to solder the board, and has a base configuration that is very inexpensive... but with plenty of options to grow. Once students master the basics of moving the robot they can add edge detection and line following boards, quadrature encoders, an ultrasonic rangefinder, additional motors (up to four DC motors and two small servos), and I2C devices such as LIDAR rangefinders and OLED displays. They can even add a speaker!

The project uses the very affordable TT Motor Gearbox, but will also work well with Tamiya Dual (and Twin) motor gearboxes, and the wheels have been designed to use cheap, readily available, silicone wristbands as tires.

And of course it starts with blinking LEDs!