Flight Computer

[Ed Dawson]

I have been playing around with GPS based rocketry components for a bit as well as the ideal flight computer.

Here’s my first pass on the all inclusive.

I wanted to find a very cheap way of receiving a rockets GPS position without having to have a complex telemetry device. So, I thought why not have if call back it’s postion via a FRS radio. Simple and easy – yet it’s not a legal use of the FRS band. Oh, well. I built a GPS device with MP3 playback and then it essentially calls back its GPS position data. After a launch detect, I read back the barometric altitude, range and bearing from the original launch position.

I wanted to launch this in the Saturn V, but the first hand made board was not stable enough. So I built a new version.
This time I decided to throw in everthing except deployment. I don’t want to mess around withe deployment at this stage as there are so many reliable products out there that I already completely trust. That frees me to play with other features.

Here’s what I have in this version:

– GPS
– Audio and MP3 playback (yes you can play your favorite songs)
– Barometric Altitude
– 3 axis Accelerometer
– Temperature Sensor
– Humidity Sensor
– micro SD memory card (2GB of memory) for data logging / MP3 files
– MaxStream 9xTend telemetry module (up to 40 mile range)
– fits in a 38mm body tube

Here’s a pic:

The next step is to further reduce the size and simplify the design. My thoughts are to build a simpler version to see if there is any interest from those in the rocket community.

Also, I want to keep it a bit modular. For example many will not wan’t a temperature/humidity sensor. I just threw it in for the heck of it.

I will also add pyro channels down in a future version. I just want to get the reliability down first.

[Jeffrey Joe HintonModerator]

Well sure, I’d do that if I were you. I’d want one. What sort of power supply is required to make it work and for how long?

[new2hprParticipant]

I’d certainly be interested. I have a much greater fear of losing a rocket than destroying one.

A long-range “here I am” call without HAM licensing would be sweet. I’ve been avoiding the temptation to join the 1 and 2 mile clubs just because of this.

I agree with keeping the deployment separate. Granted, it would be cool to have it all in one device, including DD and high-current multiple airstarts, etc. etc., but simplicity helps reliability.

Ken

[Ed Dawson]

Right now I have run it off AAs, 9V, and a rechargable RC battery. I am finding that some FRS radios have a built in battery charge on the mic input line. Since I am just using a VOX mode it draws way more than I want it to- one more thing to fix in the next revision.

I also will be evaluating whether it’s better to power the rocket’s MP3 and FRS radio, or if I should use the telemetry data and then play MP3 from the ground based computer. In the long run, I want the cheap MP3/FRS to be the priority.

However, one other reason for the MaxStream device is that I can fit it in a 38mm tube. I have not found a FRS that small yet.

Maybe an array of solar cells on the side of the rocket would take care of the power requirements….. Nah, NASA did that already.

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