An altimeter that fire a charge at apogee and beep the apogee altidude after deploying the parachute. This is really ideal for replacing the motor ejection.
For this one because I wanted to make it smaler I used an ATtiny 85. It is physically smaller than the ATMega 328;
It has less outputs, less memory ... but enought to do what we need to do.
The first prototype can be found here
This is what it looks like. Probably the simplest rocket altimeter and cheapest in the world.
The board is really small 75 x 19 mm.... which is not too bad for something using classic components. That also mean it can also be used by model rockets.
The final design of the AltiUno look like this
I have also made version with smaller transistors
You will be able to download the full documentation here.
You will be able download the kit instruction here.
You can download the code on the download page.
If you cannot do the PCB yourself or want a full kit contact me. I can provide it at very reasonable cost.