Electronics in Stratos III – The SRP follow-up

Last post I only talked about the Small Rocket Project, which is now officially closed. The after movie can be seen here. What I didn’t tell you last time, is that I joined the Electronics Team of DARE already! That means I am now working on Stratos III, the next flagship rocket from DARE.

So when the SRP was over I could immediately start working on my first task within the team, a so-called ‘Work Package’. I had to find a pressure sensor online and design the schematics for the sensor and the components that go with it. The purpose of this pressure sensor is to measure the altitude of the rocket so that when it descends, it knows when to deploy the drogue chute and the main parachute. Luckily for me, it will be only one of the voting systems that decides when those parachutes should deploy, since this is a fairly critical process.

So I started researching sensors, sifting through pages and pages of datasheets to find a sensor that would be cheap, small and survive the conditions presented by this rocket; it must be able to survive the vacuum of space. I also could not use a run-of-the-mill sensor because the sensor will be placed in the recovery bay of the rocket, some 1.5 meters away from the flight computer. Also because there are also some antennas nearby that can interfere with the signal coming from my sensor, so a different communication protocol is needed with higher voltage levels. This ensures that the signal remains relatively untouched when it reaches the flight computer.

In the GIF below you can see the progress for the layout of the pressure sensor board, taken over a month of work. Below that is the finished render of the board. Electrical engineers might already have seen that we are using Altium Designer to create this; which is very nice because it is industry-standard software that I definitely could not have gotten as a simple consumer. This software has a steep learning curve, but it is the best tool to design schematics, do the layout of the printed circuit board (PCB) and view the 3D model. Something good for my CV!

Click to check out the animation!

By now the design has been reviewed multiple times by team members and I have learnt a lot in PCB design that I can apply in the future. Now, all we have to do is order all the parts, solder the parts on the board, and test it. Can’t wait to see it in my own hands!