GPS/Video/Altimeter telemetry payload

[llobdelljr]

I've dreamed about this for years, but now thanks to the recent stimulus I might be able to afford it. I am building a payload bay for my 4" dia. L2 HPR build. I'd like a payload that includes GPS, real time video, & altimeter data sent to a ground station, and to a portable rocket locator. I also want to be able to record everything for future analysis. To minimize possible RF interactions, I'd like to feed these 3 inputs into one RF transmitter. I have a Ham license so frequency is not a problem. I am an old phart so can solder but don't have a clue about programming. Any suggestions about suppliers? The Altus stuff is a little spendy, the Featherweight GPS is iPhone only & doesn't play nice with Win10 laptops, and I'm having someone assemble an Eggtimer Quantum for me to try. There is probably some video equipment out there for 2.4 GHz drones?
Thanks, Larry

 

[OverTheTop]

Have a look at www.hobbyking.com for possible video telemetry equipment. Some of the flight controllers also do video overlay so can put the gps information on the video frame.

Good luck with the project .

 

[ksaves2]

Ya wanna save money? Just use a keychain camera and GPS tracker and look at the video when you get the rocket back. A heck of a lot cheaper than trying to view in realtime. Antenna polarity issues, poor reception of the video stream and the investment it will take for the radio transmitter that will handle the video stream. Are you a Ham radio operator? If so, there would be more options available to you but still, would take much more time to hash out, trouble-shoot and just increases the complexity of the setup.

Oh, what might work for a slow speed drone might not be all that great for rocketry. Don’t get me wrong. It has been done before but the rockets I saw using it (a long time ago) were large and used Ham equipment. On an L2 rocket just put a camera on the side, use the GPS tracker and concentrate on pulling off the certification. Don’t add the complexity of the electronics.

Another thing. When dealing with an Rf transmitter, the transmitted signal can do crazy thing to one’s deployment electronics. As in like malfunctioning the deployment altimeters. I’ve been bit by it and I’ve witnessed one stupendous failure of a very large project in the past. True, the modern deployment devices
are more immune to this but an all up ground test is a good idea.

Stick your GPS tracker in a nosecone bay so your deployment electronics ride aft. If you stick a TV transmitter in your eBay with your deployment device that could be a problem. If you elect to go that route, do an all up ground test with contained ematches on all the outputs of your deployment devices. Put your rocket upright in the backyard. Turn everything on, tracker, TV transmitter (if used) and the deployment devices last. Let sit for 30 minutes or more. If the matches don’t fire or the
“Ready” beeping doesn’t stop you stand a chance the setup will work. If the RF from your tracker or TV transmitter interferes with the altimeter, the matches might fire OR the altimeter(s) go into standby mode and won’t function at all. Need I say “core sample” will follow if that happens during the actual launch and a DNF for “did not finish” Good luck. Kurt

 

[FMarvinS]

Larry,
I wholeheartedly agree with Kurt's recommendations. Place the GPS in the nose cone and the altimeters and a tracker (e.g. BRB 100 mw 440 MHz or the new eggfinder 70 cm tracker) in the AV bay. As stated, altimeters placed close to a GPS transmitter (probably > 250 mw out) in an AV bay may cause the altimeters to fail. Some older posts document the same for video transmitters. MFG sells a small video camera/transmitter which is low power and has been shown to be relatively safe in flight. However, it is black and white, low power, and requires a UHF portable TV for reception (old school!). This unit in the past cost about $100. The problem with the use of drone video transmitters is the high frequency and relative low power out probably means reception may only be good for a few thousand feet at the best. Furthermore, as Kurt pointed out antenna polarity will be an issue. Its probably best to use a mobius and view the SD card recording post flight. Finally, one of the metrums has a built in telemetry. Also, several other altimeters are capable of telemetry also (stratologger, eggfinder and Missile works; however, you'll have to supply the transmitter and coding for these options). Each component will take trial and error to get it to work efficiently. The GPS, tracking, and mobius camera alone will each take time and practice to learn. I'd suggest do them sequentially. So, possibly for the L2 launch, just the addition of the GPS, and tracker pls/minus a mobius camera setup will be challenging.
Good luck!

Fred, L2
ICBM, Camden, S.C.
KG4YGP

 

[KilroySmith]

Well, I just made this suggestion in another thread, but it's applicable here also.

Put in a 2-year old cellphone. Use a video conferencing app to see the real-time video from the rocket. Use the phone's LTE (as long as it's available where you launch) for the data link for GPS, Video, etc.

I know, I know, not nearly as much fun as wiring up modules to a 2M transmitter.

 

[rharshberger]

Dont forget to buy a barf bag, and be sitting down for the flight, unless you dont get motion sick because a lot of rockets have a pretty quick roll rate that could make real time video amusing for bystanders.....