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Hardware Needed for Real-time Telemetry of Alt, Vel, and Acc, to 10,000'?

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philoarktiko

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[FONT=&amp]Friends!! I am part of a university competition to get a solid-fueled rocket to 10,000 feet carrying an 8.8 lb payload. I signed up to be a member of the team working on avionics. Although I'm a Mechanical Engineering guy, I love the idea of giving my rocket a brain and knowing much more about my launch than just "wow, that was loud and went really high! Oh, how high, you ask..? Well, um, judging by the angle of the launch as seen on my point-and-shoot camera…" etc. I want lots, lots, lots of data on this flight! -we're students and we need to be learning some real rocket science! I hope to do much analysis and writing reports on comparing this data with all our models and simulations.[/FONT]

[FONT=&amp]I'm also a bit of a software guy, so that part isn't a problem. My main problem is the hardware. I GREATLY desire to have a ground station with real-time telemetry of maybe 20 Hz+. When I say telemetry, I don't mean just lat/long position - I also want velocity, acceleration, and (of course) altitude! I want to be able to see it as close as possible to real-time on my laptop through the rocket's ascent and descent. I know very little about the hardware needed for this, but I have an idea. I've done lots of reading on this forum (you guys are seriously all wonderful people and are truly an inspiration), and I have found a few things, but from several years past and many of the mentioned hardware is no longer being sold or is outdated. :/ It's October 2016 now - there must be newer stuff out, right?[/FONT]

[FONT=&amp]One thing I understand may be a problem is the range. I've seen a great deal of information on telemetry for smaller ranges (<1 mi) but I believe I will need a range of at least 5 miles in case the atmosphere decides to take our rocket on a great journey across the desert. I've seen this module and was wondering everyone's opinion on it: XBee-PRO XSC S3B RF Modules Expansion (http://www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=185906993). Is this sufficient, and is there anything newer? I know there are some pre-assembled devices out there like the Eggfinder, but I was kind of hoping to get something a little more DIY than that, I think. I'm new to this, but learning engineering skills and principles in multiple fields is the main point of this project, so I want to learn![/FONT]

[FONT=&amp]My team wants to make a flight computer using the Arduino UNO. We may have two for redundancy (all the measurement devices x2). We are planning on storing all the vel/acc/pos/alt data on board already, but as I said I want to transmit this data to the ground, also. Can this be done using the same hardware, e.g. will I need an altimeter for onboard data collection and a separate altimeter for telemetry, or can the same altimeter do both? Sorry, I'm not an electrical engineer!![/FONT]

[FONT=&amp]So far, I understand I need the following:[/FONT]
[FONT=&amp]Onboard transmitter[/FONT]
[FONT=&amp]Receiver (USB connection)[/FONT]
[FONT=&amp]Antenna for increasing range[/FONT]
[FONT=&amp]All the measurement devices for acc, vel, pos, alt[/FONT]
[FONT=&amp]Microcontroller (Arduino UNO)

What else is needed? I'm trying to assemble a FULL list of exactly what is needed to accomplish this. I'd like a medium level of DIY and I will probably be on a tight budget. This should all be compatible with an Arduino (probably UNO).

[/FONT]
[FONT=&amp]You guys are awesome! Thanks for the help![/FONT]
 

cerving

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You can do this with an Arduino and any of the available barometer and accelerometer modules that are out there (look at SparkFun). 10,000' is really not much of an issue, especially in clear air. For the RF side, you can use a pair of the Digi modules, or if you're looking for GPS data too you can get an Eggfinder TX transmitter and the Eggfinder RX "dongle" receiver for about the same price, and wire it up so your data is sent in the empty space between the GPS data feeds. Since you're gonna have a laptop to read the data anyway, you should be able to write something that will make the data look pretty, either as it comes in or post-flight. You should be able to do the whole thing for just a bit over $100, and that includes a GPS feed.
 

keithp

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I build commercial rocketry electronics that already do what you want, but that doesn't exactly make for an interesting electronics project. I completely understand your desire to build something on your own. However, I've also worked with a number of university teams participating in both ESRA and NASA SLP and seen what sorts of problems they've had.

First off, I strongly encourage the use of a commercial flight computer to deploy the recovery systems. The combination of a single-board hardware design with software that has flown thousands of flights reduces the safety risks associated with the hardest part of any rocket flight.

I also encourage the use of a commercial tracker of some kind; either a GPS unit (like those made by us (Altus Metrum) or Big Red Bee) or a simple radio direction tracker like a Walston. Having a system with known performance will increase the odds of finding the rocket after the flight.

You can still include GPS data in your own telemetry stream, and rely on the commercial tracker solely as a backup. XBee modules can provide sufficient range to collect lots of data during ascent, although getting the antennas pointing in the right direction from inside the airframe is a challenge. Ground testing can uncover all kinds of issues; make sure you try orienting the airframe as it would be in flight relative to the ground station antenna. Often times, the ground station will end in the worst part of the rocket's antenna pattern.

Good luck!
 

FredA

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+1 with Keith.....

Use proven technology.
I too mentor these competitions and have seen way to many "home grown" electronics be the cause of team failures.

Success at these competitions depends on making WISE choices and not about DOING-EVERYTHING yourself.
 

philoarktiko

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First off, I strongly encourage the use of a commercial flight computer to deploy the recovery systems. The combination of a single-board hardware design with software that has flown thousands of flights reduces the safety risks associated with the hardest part of any rocket flight.
That makes a lot of sense. I've had my fair share of rocketry failures, so I understand. Since we just started this club at our university and by some miracle received funding, we don't want to kill our reputation because of a failed first launch. A certain faculty member really believes in us and went through a lot to get us the resources we needed. For our first competition, it makes sense to play it safer and do less of our own "home grown" electronics/software.

Thank you for the suggestions cerving - I will look those up!
 
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CORZERO

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If you want FPV, follow these guys. Everything they achieve, can be achieved with rocketry, just apply yourself:

[video=youtube;CTZvqen8tJY]https://www.youtube.com/watch?v=CTZvqen8tJY[/video]
 

CORZERO

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I apologize for the above post. If those who are interested in the above wish to partake in the next wallet-draining hobby, please refer to this post:

[video=youtube;FHtw6g3DkQo]https://www.youtube.com/watch?v=FHtw6g3DkQo[/video]

Then watch this:

[video=youtube;VUu_oRj38uQ]https://www.youtube.com/watch?v=VUu_oRj38uQ[/video]

Welcome to another dimension......
 

cerving

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+1 with Keith on this. Rolling your own telemetry can be a fun project, I've seen a lot of university projects in SoCal that do just that. I've also seen university projects go wayward, or get stuck 5' in the ground... go with a proven commercial product for deployments and tracking. [The disclaimer...]I make commercial stuff too, and believe me there's a lot of flight testing involved before anything ever gets out in the wild, and even after that you can occasionally run into something that you'd never find with just a few flights. It usually takes about a dozen test flights with everything from little 24mm motors up to L2 motors to get above Mach before you can feel confident with the software in a new deployment controller. If you're trying to do this in a university setting, that testing just isn't gonna happen; you most likely don't have the time, space, or the rockets & motors to test it.

First off, I strongly encourage the use of a commercial flight computer to deploy the recovery systems. The combination of a single-board hardware design with software that has flown thousands of flights reduces the safety risks associated with the hardest part of any rocket flight.

I also encourage the use of a commercial tracker of some kind;...
 

jderimig

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This is a UNIVERSITY engineering project not a private enterprise. The primary objective is to learn first, succeed 2nd. Design and build your own system. Use commercial OTS units as benchmarks. Test both. Embrace the opportunity for failure in the pursuit of learning.

But yes, this approach increases the risk of some failure.
 
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cerving

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My suggestion is to use a commercial product for the recovery, possibly the tracking, and then you can concentrate on the telemetry which is the primary objective. Although success may not be the primary objective, the cost of failure has to be weighed too... loss of time and money. If you want to do deployments too, great, but have your controller ride along as a backup unit for a commercial unit for a few flights until you're satisfied that it's ready.
 

jderimig

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My suggestion is to use a commercial product for the recovery, possibly the tracking, and then you can concentrate on the telemetry which is the primary objective. Although success may not be the primary objective, the cost of failure has to be weighed too... loss of time and money. If you want to do deployments too, great, but have your controller ride along as a backup unit for a commercial unit for a few flights until you're satisfied that it's ready.
Chris's advice is correct and better than mine, upon reading the Spaceport America Cup rules up to 100 points is awarded for SRAD (student researched and developed content) but 500 points are awarded based on the success of the flight. Make sure the flight is successful, no contest.
 

FredA

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All the contests I am aware of frown greatly upon splattered rockets.
A safe return is paramount.

Focus on bringing it back safely.
Then add all the bells and whistles you can in the time remaining.
 

Earache

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I've had over 400 students design and fly electronics on rockets. I strongly support the idea that you use commercial for recovery and tracking. Eggtimer Rocketry's stuff is currently the cheapest and has a very high reliability. Since you have to assemble them, there is still a lot of learning involved.

If you want to add your own system for telemetry and sensors for acceleration, velocity, and position, you can. I strongly recommend you use a Teensy instead of an Arduino Uno. It is much faster and more powerful, about the same price, and uses the Arduino development environment. I built and flew a Teensy-based system recently. I didn't have telemetry (but there are several options) but I used an Adafruit Ultimate GPS Breakout #746 for GPS, a SparkFun IMU Breakout - MPU-9250 for acceleration, rotation rate, and orientation, and a Pololu LPS25H Pressure/Altitude Sensor Carrier with Voltage Regulator #2427 for pressure altitude. I wrote all of the data to a microSD. I also had commercial hardware for recovery and GPS tracking. My system easily met your 20+ Hz sampling rate, so what you want to do is possible, but I strongly recommend the Teensy if you want the Arduino envirounment.

Here's a shot of the system.

TeensySystem.jpg
 
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DavidMcCann

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From ten thousand you should be able to easily put down within a mile. That said, crazy stuff does happen.
 

OverTheTop

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It is really tempting these days to do "plug-and"play" development with things like the Arduino (or similar) and the various sensors. It is a great learning experience and goes a long way to developing more capable engineers and technical people. It just seems really easy to get a good result.

Having said that, you often don't know what you don't know. Rocketry can have a lot of this unless you ask a lot of questions and/or are very lucky. You don't want to rely on luck. Using commercial altimeters takes the luck variable out of your recovery. Nobody wants any flying fenceposts.

Keeping the above in mind, don't let it stop you with developing your own stuff. Have fun!
 
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