Building the Ideal Arduino-Based Rocket Launch Controller

When I was a kid in the ‘90s building model rockets with my dad, the hobby launch controllers on the market were basic to say the least. They really weren’t much more than some batteries in a box with a switch. And surprisingly, that is still how many of them are. But with modern technology, Markus Bindhammer of Marb's lab was able to build something much better on a modest budget.

This is a launch controller for model rockets with motors triggered by e-matches. Those e-matches only need a tiny amount of voltage (usually less than one volt) and not much current (usually above 700mA) to ignite the rocket motor. You could do that just be touching the leads to a AA battery. But safety and precision control are nice, which is where Bindhammer's controller comes in.

It can trigger up to four e-matches, using an Arduino Nano Every development board to control current going to those contacts. There is a locking switch with key, so unauthorized users can’t arm the system. The onboard interface lets users adjust parameters, like a timer delay. A machine-style tri-color indicator light provides status information from a distance and a buzzer counts out the time to launch. Those components all fit in a custom 3D-printed enclosure, with a custom PCB inside to keep everything tidy. Power comes from a LiPo battery.

When everyone is clear and ready for launch, the user can simply tap the big red “ignition” button and the countdown sequence starts.

Bindhammer hasn’t shared this design, but it should serve as inspiration for other model rocket enthusiasts.