Water Rocket with Raspberry Pi – V2
You can see the first version of the rocket here: Water Rocket with Raspberry Pi – V1
As explained in V1, the parts needed for water rocket are: Bottle, Nozzle, Fins, Release mechanism, Head of rocket (holding parachute & flight computer), Parachute and Flight Computer (hardware and software)
AircommandRockets website has tons of amazing tutorials related to water-rockets: http://www.aircommandrockets.com
For V2 we have redesigned the Head of the rocket. In V1 we have used the simplest head, a cutout from a plastic bottle with the inside mechanism of cardboard/foamboard. The new head cone is completely 3D printed, easily replaceable after a crash.
V2 has a completely 3D printed head
The door is fixed with a metal rod created from a paperclip.
And the components (flight computer, parachute release mechanism, sensors) are all mounted on a 3D printed part.
In the next picture you can see the battery with the charger on top, and on the side the raspberry pi zero with the camera.
In the next picture we have the motor that is releasing a rubber band opening the parachute door. Also on the bottom part we have the accelerometer and the pressure sensors.
In the next picture we have the parachute compartment, with rubber bands used to push the parachute out when the door is released.
We had some fun sanding the 3D parts to nicely fit into the head of the rocket.
Flight Computer Software
In order to release the parachute of the rocket after the descent is detected we are using raspberry pi and accelerometer sensors. The software is simple, written in python.
Full source code can be found here: https://github.com/smarcu/dnd-water-rocket-raspberry
Rocket Head 3D model
With the V2 we had launched several times, we still had some software algorithm problems (the descent detection was not working properly).
We had several crashes, but the head was quite solid, the cone and the shell absorbed most of the shock and the inner components were not affected.
The best launch we had in the beautiful county of Hateg!