Hello everyone, I'm working on a university project to build a rocket model, and I would like to try and setup a live telemetry with ground station. we're still finalizing the design stage so I have some room for flexibility.
I'm thinking on using two Xbee Pro S2B transceiver chips.
1- Can you advise which antenna to use for my application? the rocket will be launched in an open field, so clear line of sight, and the altitude will not go above 1000 meter for sure.
2- I would like to transmit the data and store them on an SD card in the rocket as well.
3 - since communication is not my major, I'm having trouble understand how to calculate the amount of data that I'll be able to transmit to the ground stating using the Xbee, and considering that I'm moving away from the ground station.
I've read the attached document, however I still didnt get how to calculate the data rate, to know if I'll be able to send a video and sensor data from the rocket to the ground station.
Hello @zwieblum , thank you for your reply!
I just checked these models, they seem designed for RC planes and drone control no?
Our rocket model will not have any control surfaces, its for propulsion system testing. we will be using an arduino nano as a micro controller, and we have other peripherals connected to it to measure temperature, pressure, etc. I would like make a communication with the ground station to transmit these data in live stream, as well as store them on an SD card in the rocket.
Does the Radiomaster TX16s still work in such a case?
Otherwise please advise.
They are. But as you know FPV drones have telemetry backchannels (quite a lot of them) and datalogging. That part you'd like to use. And then there is great community support for ELRS and EdgeTX.
can you advise a way to calculate this? I need to be able to prove that using the arduino nano, with the Xbee transceiver will be enough to transmit all the data.
Define "all the data". Then set the precision of each value. Then define how often you want to receive which value. Sum it up --> you know your demand.
thank you, ok so I have for example a gyroscope & accelerometer (for example GY-521), 2 Thermocouples with amplifiers, 2 pressure transducers, and camera 2 Mp. how do I find the precision of each value?
Take a look at what the sensors send you. 2 bytes per vlue, 1 byte? which accuracy do you want? 1/256 of whatever or more? If you are happy with 1byte per value: 3xACC+3xGYRO+2xBARO=>8 byte -> 80 bit (8+start/stop) -> 9600/80 => 120 Hz - that's a lot. or 60 Hu when 2 byte per value - still a lot.
Camera ... no way with anything like LoRa, XBee, whatever. Get HDZERO goggles or use analog and a really good directional antenna ... but that's a question for a different forum ( Aircraft - Electric - FPV - RC Groups )
Can't you consult with whoever on your team is doing the instrumentation? It doesn't seem fair that they stuck someone with absolutely no knowledge of the subject material with this fact finding mission.
+1. They sound awesome in the marketing materials. They perform reliably much less so, in my experience in AT mode (ordinary wireless serial/transparent mode). They were great to 60m LOS while moving, 100m stationary on the ground in a football field (that was as I recall the best I got out of them, never used them for flying).
@zwieblum Thanks a lot, I think its clearer now, I'll make more research and reading about this, if anything not clear will revert back. Much appreciate the help!
@EmilyJane It's a university project, I welcome the opportunity to learn stuff that I don't know about, and thankfully there is a community to support in the learning curve, I'm trying to rely on that.
@hallowed31@zwieblum, thank you! Can you recommend a transceiver chip that I can use on the rocket model and ground station? for the rocket I need it to be compact, small size, and be able to transmit the data I from sensors I mentioned above up to 1000 meters. if possible to add a video that would be great otherwise just the telemetry. Also keeping in mind that we're using a Lipo battery in the rocket, 7.4V 1050 mAh, so power capacity is limited.
You probably will have to look into LoRa. Data rates will be more limited than with some other communication methods, but depending on your requirements (see my comments in your other thread...) it may be adequate.
The ones I used in a hexacopter were 3DR telemetry radios (which, funnily enough I think use Xbee technology in them to some extent) but i really don't know if this is suitable for your purpose based on noise, range (I never flew beyond a few hundred feet) or payload requirement.
2s1050 as a payload is huge! Your rocket won't fly for hours, some minutes at best. I still advice for ELSR - it's proven and reliable for long range. If you feel better, it's LoRa, but you don't have to dig into the details when you buy the modules.
One thing to read (well, hackaday, but ok):
search for arduino+elrs, you find a lot of projects.