Telemetry

[Landon_Jace]

My high school senior class is building a hybrid rocket to achieve and altitude of 50,000 ft. or 15,240 m. I am in charge of the payload and telemetry portion of the rocket and am a bit confused on what to do. The system must include barometric pressure, an accelerometer, GPS, and tank pressure/temperature. I just need some general advice on frequencies to use and how to make a system that can communicate that far. we were thinking of using Arduino but I'm new to it so I don't know if it would work? Any help would be much appreciated.

 

[DAllen]

Take a look at the Eggtimer Rocketry suite of products which I believe will get you part of the way there.

https://eggtimerrocketry.com/
50k? Yikes. Where do you plan on doing a flight like that? And does your school have any experience with such an ambitious project?

 

[Rocketclar]

I use to live in central TX. I suspect OP is with their Systems GO program at the school. I've been to one of their launches and they use hybrids. For big projects like this I suspect they will launch again at White Sands.

 

[Landon_Jace]

Take a look at the Eggtimer Rocketry suite of products which I believe will get you part of the way there.

https://eggtimerrocketry.com/
50k? Yikes. Where do you plan on doing a flight like that? And does your school have any experience with such an ambitious project?

Thank you so much for the advice I will definitely look into it! As for the location Rocketclar is exactly correct. I'm with the Systems Go program and we will launch the rocket at white sands missile range which I'm really looking forward to.

 

[Landon_Jace]

I use to live in central TX. I suspect OP is with their Systems GO program at the school. I've been to one of their launches and they use hybrids. For big projects like this I suspect they will launch again at White Sands.

Was it a recent launch? If so my classes rocket might have been there.

 

[Titan II]

White Sands is correct. Nice program!

https://www.systemsgo.org/

 

[Landon_Jace]

White Sands is correct. Nice program!

https://www.systemsgo.org/

I really love the program and I hope it spreads all around the country. I believe there is a school in Abu Dhabi which is pretty crazy so I guess its on its way to becoming worldwide.

 

[Rocketclar]

Was it a recent launch? If so my classes rocket might have been there.

I think it was 2018. The Alamo Rocketeers set up a little booth there and we displayed some rockets and talked with students. My Stinky Sewer Pipe rocket was one displayed.
I second Eggfinder Rocketry. I have built at least one of everything he has. The kits are well documented and he provides a lot of practical info on rocketry as he's active in the hobby. I have built several of his telemetry modules and have the voice module too. I've patched the voice module into the club's PA (after verifying that the LCO could over speak it in case of an emergency) so the audience can hear the real time outputs of altitude, channel status, etc. Always a crowd pleaser.

 

[kjhambrick]

Systems Go is an outstanding program that I learned about earlier last summer.

What is an excellent opportunity @Landon_Jace !

+1 for contacting @cerving from EGGTIMER ROCKETRY, especially if you want to 'do it yourself' with your avionics package

I've never met Cris in person but he seems like a great guy from reading his content here on TRF.

There are a lot of experts to tap for their experience here on TRF ( I know that I do )

Good luck and please keep us up-to-date on your progress as you go !

Thanks !

-- kjh

 

[Kane]

+2 on the Eggtimer products. For your program requirements listed in your post, you"LL want to look at the Proton. It has six event channels which may be overkill, but it's the only offering that includes an accelerometer. It uses a barometric sensor and accelerometer to gauge altitude, velocity, acceleration, etc. It also records the temp, but that's atmospheric temperature, not tank temperature. If your requirements are that you need the raw pressure data from the baro sensor, I'm not sure if you're able to parse that from the data that is recorded and transmitted. Tank pressure and temp may need to be provided by a separate package. The Eggtimer Telemetry module and be plugged into the Proton and will transmit the telemetry data to an Eggfinder LCD Receiver in your ground station. For tracking the Eggfinder GPS or GPS Mini transmitters are the way to go. However, their range is under your program altitude so you would need to get the 70cm version of the Eggfinder GPS which requires FCC amateur HAM license. Also not that you need separate receivers for the GPS radio and telemetry radio.

 

[Voyager1]

My high school senior class is building a hybrid rocket to achieve and altitude of 50,000 ft. or 15,240 m. I am in charge of the payload and telemetry portion of the rocket and am a bit confused on what to do. The system must include barometric pressure, an accelerometer, GPS, and tank pressure/temperature. I just need some general advice on frequencies to use and how to make a system that can communicate that far. we were thinking of using Arduino but I'm new to it so I don't know if it would work? Any help would be much appreciated.

Probably the most challenging of your requirements is the hybrid motor's flight tank pressure. The tank temperature can easily be monitored with a thermocouple, or digital temperature sensor, interfaced to an Arduino. However, I don't know of any of the readily available hybrid motors that would be easily modified to accept a flight tank pressure sensor. Any modification would make it an experimental motor and launch. I assume that your group is not building their own hybrid motor.

 

[Landon_Jace]

Probably the most challenging of your requirements is the hybrid motor's flight tank pressure. The tank temperature can easily be monitored with a thermocouple, or digital temperature sensor, interfaced to an Arduino. However, I don't know of any of the readily available hybrid motors that would be easily modified to accept a flight tank pressure sensor. Any modification would make it an experimental motor and launch. I assume that your group is not building their own hybrid motor.

I’m not personally on the fuel grain or tank team but I believe they are designing both entirely from scratch and getting the tank custom built exactly for the purpose of monitoring the pressure during flight. This has definitely been one of the most challenging parts so far but we are only about 3 weeks into research and everyone’s advice on here will really help. Thank you for the advice.

 

[Landon_Jace]

+2 on the Eggtimer products. For your program requirements listed in your post, you"LL want to look at the Proton. It has six event channels which may be overkill, but it's the only offering that includes an accelerometer. It uses a barometric sensor and accelerometer to gauge altitude, velocity, acceleration, etc. It also records the temp, but that's atmospheric temperature, not tank temperature. If your requirements are that you need the raw pressure data from the baro sensor, I'm not sure if you're able to parse that from the data that is recorded and transmitted. Tank pressure and temp may need to be provided by a separate package. The Eggtimer Telemetry module and be plugged into the Proton and will transmit the telemetry data to an Eggfinder LCD Receiver in your ground station. For tracking the Eggfinder GPS or GPS Mini transmitters are the way to go. However, their range is under your program altitude so you would need to get the 70cm version of the Eggfinder GPS which requires FCC amateur HAM license. Also not that you need separate receivers for the GPS radio and telemetry radio.

Thank you so much for the detailed advice. One of the most challenging parts has been knowing where to even start because I can’t find much on the internet with the requirements we need to meet so this will help tremendously. Much appreciated

 

[Landon_Jace]

I think it was 2018. The Alamo Rocketeers set up a little booth there and we displayed some rockets and talked with students. My Stinky Sewer Pipe rocket was one displayed.
I second Eggfinder Rocketry. I have built at least one of everything he has. The kits are well documented and he provides a lot of practical info on rocketry as he's active in the hobby. I have built several of his telemetry modules and have the voice module too. I've patched the voice module into the club's PA (after verifying that the LCO could over speak it in case of an emergency) so the audience can hear the real time outputs of altitude, channel status, etc. Always a crowd pleaser.

UnfortunatelyI don’t think I was in High school at that time. But thank you for the advice. I will definitely have to look into the voice module. My classmates would enjoy that very much.

 

[Titan II]

Any modification would make it an experimental motor and launch. I assume that your group is not building their own hybrid motor.

This is not TRA or NAR.

https://www.bringonthescience.com/Grade-12

 

[Titan II]

https://www.rocketryforum.com/threads/looking-for-telemetry-system-for-high-altitude-rocket.150983/
https://www.rocketryforum.com/threads/radio-questions-for-telemetry-transmission.179521/

 

[cerving]

There are a number of university teams doing similar projects, you may want to contact them to ask about their telemetry and tank pressure sensors/RF links/dashboards. I was out at FAR (friendsofameateurrockety.com) yesterday and there was a group from UC Berkeley that was doing a bipropellant static test, I know that the Cal Poly universities are doing stuff like that too. Chances are good that there is a university in TX closer to you that's doing hybrids or bipropellants.

An Arduino (think 32-bit) could definitely be used as the processing engine for your telemetry, but you'll need sensors and a good RF link too. You'll also want to record data on local memory during the flight, if you lose your RF link during the flight you'll still have the data.

 

[Voyager1]

I’m not personally on the fuel grain or tank team but I believe they are designing both entirely from scratch and getting the tank custom built exactly for the purpose of monitoring the pressure during flight. This has definitely been one of the most challenging parts so far but we are only about 3 weeks into research and everyone’s advice on here will really help. Thank you for the advice.

All the best with the project. Sounds challenging, but a great experience.

 

[Spacedog49Krell]

Which propellants are you considering for your hybrid? If you are using Nitrous Oxide as the oxidizer, my favorite, there are a number of compatible pressure transducers that are readily available that easily interface to Arduino based flight computers. If you need to assemble your own flight computer system, I advise using SparkyVT's code on GitHub. He is a member here on Rocketry Forum. His code has been flight proven using the Teensy 4.1. The code collects critical flight dynamic parameters at 1000Hz and other parameters like; barometric pressure, temperature, and GPS at slower data rates. It also interfaces to LoRa and HAM telemetry modules. Do not be intimidated by the 1000Hz data rate. If you fly your hybrid, you will quickly discover the need to record critical parameters at 500Hz to 1000Hz when things go wrong.

John Krell

Advisor on UCLA Project Ares Liquid Rocket
Former advisor on Compton Comet Liquid Rocket
Former advisor on EPDM for USCRPL Traveler 3 & 4

 

[rocket_troy]

Probably the most challenging of your requirements is the hybrid motor's flight tank pressure. The tank temperature can easily be monitored with a thermocouple, or digital temperature sensor, interfaced to an Arduino. However, I don't know of any of the readily available hybrid motors that would be easily modified to accept a flight tank pressure sensor. Any modification would make it an experimental motor and launch. I assume that your group is not building their own hybrid motor.

On the (what's now evident) hypothetical that you were constrained to the non-modification of a commercial hybrid tank, Vapour pressure should be directly proportional to N2O temp; so you should get close by measuring temp. However, if you wanted to measure pressure directly without invasive surgery, you can perhaps even do it directly with a strain gauge mounted to the tank's surface to primarily measure radial strain. Pass that to an INA122 instrument amp, set the appropriate gain (generally 1000ish) and feed that into a typical A>D input of your favourite flavoured micro.

TP

 

[Landon_Jace]

Which propellants are you considering for your hybrid? If you are using Nitrous Oxide as the oxidizer, my favorite, there are a number of compatible pressure transducers that are readily available that easily interface to Arduino based flight computers. If you need to assemble your own flight computer system, I advise using SparkyVT's code on GitHub. He is a member here on Rocketry Forum. His code has been flight proven using the Teensy 4.1. The code collects critical flight dynamic parameters at 1000Hz and other parameters like; barometric pressure, temperature, and GPS at slower data rates. It also interfaces to LoRa and HAM telemetry modules. Do not be intimidated by the 1000Hz data rate. If you fly your hybrid, you will quickly discover the need to record critical parameters at 500Hz to 1000Hz when things go wrong.

John Krell

Advisor on UCLA Project Ares Liquid Rocket
Former advisor on Compton Comet Liquid Rocket
Former advisor on EPDM for USCRPL Traveler 3 & 4

Yes we are using nitrous oxide. I believe the pressure transducer we are looking at currently is the Omega Px309 mainly due to the cost. We are working with a pretty tight budget so keeping it relatively low price is a big deal. If you have any other suggestions I would love to hear them and thanks for the advice it will definitely help a lot!

 

[Landon_Jace]

On the (what's now evident) hypothetical that you were constrained to the non-modification of a commercial hybrid tank, Vapour pressure should be directly proportional to N2O temp; so you should get close by measuring temp. However, if you wanted to measure pressure directly without invasive surgery, you can perhaps even do it directly with a strain gauge mounted to the tank's surface to primarily measure radial strain. Pass that to an INA122 instrument amp, set the appropriate gain (generally 1000ish) and feed that into a typical A>D input of your favourite flavoured micro.

TP

Wow I never even thought about that I will definitely have to look into a strain gauge or perhaps even finding the pressure based on temperature. Cost is a big issue so if its possible to get the pressure without having to buy a 400$ PT then that’s something Ill have to see about. Thanks for the advice.

 

[rocket_troy]

Wow I never even thought about that I will definitely have to look into a strain gauge or perhaps even finding the pressure based on temperature. Cost is a big issue so if its possible to get the pressure without having to buy a 400$ PT then that’s something Ill have to see about. Thanks for the advice.

I used that exact approach to measure the gas pressure in my pyroless deployment device's chamber where auxiliary componentry size was of paramount importance. For that particular application I was able to utilise a full bridge SG due the reasons I explained in the spreadsheet, but even a 1/4 bridge will get you within a close enough ball park for that application.

http://www.propulsionlabs.com.au/Pyroless_Release/page9.htmlThe spreadsheet mentioned is linked within.

TP