ESP32 Robot Car School Edition: Easy Build for Kids

Why a School Edition?

My daughter asked me to run a robotics workshop at her primary school. The robot car from my book "Roboter-Autos mit dem ESP32" (Rheinwerk Verlag) is a great project. But it is too complex for a project day with kids in grades 3 and 4. So I designed a simplified School Edition.

The rules were simple. As few parts as possible. As few wires as possible. And a controller every kid already knows. No soldering. No programming on a laptop. But still enough technology to understand what happens inside a robot.

In the end, six cars were ready. The kids completed them in teams of two or three.

The Components

For the kids, I linked every component to a simple picture. That worked really well.

• ESP32 as the brain: mounted on a breakout board, so jumper wires plug in easily.
• L298N motor driver as the muscles: the brain gives quiet commands, the motor driver gives the motors real power.
• Two TT gear motors: they drive the two wheels. A small furniture caster runs at the rear.
• 3x 18650 Li-ion cells: about 11 V.
• LM2596 step-down converter with voltmeter: limits the motor voltage to about 7 V.
• HC-SR04 ultrasonic sensor: measures distance like a bat with call and echo.
• OLED display: shows name, connection status, mode and distance.
• Cable with inline switch: a simple on/off switch.
• PS5 or PS4 controller: every kid knows how to use it.

What Is Different From the Book Version?

• Only two motors. Steering works like a tracked excavator. If the left wheel turns faster, the car turns right. Kids get it immediately.
• Step-down converter. The TT motors do not get the full battery voltage. The cars stay controllable and the motors last longer.
• Prepared in advance. Power wiring is soldered and the firmware is flashed before the workshop. The kids only do the steps they can really understand.

3D-Printed Parts

The parts are add-ons for the round base plate of my modular ESP32 robot car chassis: an electronics plate with fenders, a roll bar with stabilizer, a front plow and push-in mounting pins. The plow protects the ultrasonic sensor during the inevitable crashes.

Download the STEP files on MakerWorld:ESP32 Robot Car - School Edition for Kids

The base chassis: ESP32 Robot Car Chassis - Modular & Open Source

Assembly on Project Day in 4 Steps

• Wire the motor driver: four jumper wires connect the motor driver to the ESP32. IN1 to P13, IN2 to P12, IN3 to P27, IN4 to P33.
• Switch on: quick check first. Are the batteries in correctly? Are all wires plugged in? Then switch on.
• Set the motor voltage: turn the potentiometer on the step-down converter until the voltmeter shows about 7 V.
• Pair the controller: teams pair their controllers one after another. Otherwise a controller may connect to the wrong car.

After that, every team visits the little "workshop". There I check the wiring and the straight-line driving. Two motors never run exactly the same, so the car drifts at first. The kids learn to spot and correct it.

Three Driving Modes

The kids switch modes with the square button on the controller. The OLED display always shows the active mode.

• Manual: drive and steer with the left stick. The display shows left and right motor power in percent.
• Distance: the car measures the distance to walls and obstacles. The kids also try to find the maximum range.
• Auto: the car drives on its own and avoids obstacles. Put it on the floor first!

In between, the kids designed a face and a name for their car with cardboard, paper and pens. My favorite was "Blitzschnell" (lightning fast).

Conclusion

Less is more. Two motors, four signal wires and a step-down converter leave enough technology to be amazed. And there is still enough time for driving, measuring and asking questions. That is exactly what the kids want.

Resources

• Technical blog post (German): ESP32 robot car for school
• Report about the school project day (German): Talent day at my daughter's primary school
• Robot and ESP32 tutorials on my blog: custom-build-robots.com
• More 3D models on MakerWorld: makerworld.com/en/@Ingmar_Stapel
• My book "Roboter-Autos mit dem ESP32" (Rheinwerk Verlag, in German): rheinwerk-verlag.de
• Control the robot car with a PS4 or PS5 controller: Hackster project