Electronic Payloads for rockets

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The EGE
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Electronic Payloads for rockets

Postby The EGE » Sun Jul 05, 2009 5:49 am UTC

I've just acquired a new large rocket - a Cosmodrome Nike Apache - for my Level 1 certification. It's got a large forward tube area, about 24mm inside diameter by 300 to 400mm long, that I intend to use as a payload bay. It does not normally carry anything during the flight, and it does not get pressurized by the ejection charge.

I'm looking for some sort of payload or payloads, preferrably to build myself, to carry inside the payload bay. They can be electronic instruments like sensors or alitmeters, or some sort of experiment that doesn't necessarily have to be electronic. (Altitudes achieved will be about 400 feet on an E motor, 800 on an F, 1300 on a G, and 2000 to 2500 on H motors. 3500 on an I is possible.)
Qualifications:
    Durability: This payload will experience 1 to 3 seconds of acceleration at up to 15 Gs during boost, as much as 50 Gs momentarily during ejection and parachute opening, and a sudden drop from 25fps to zero on landing. It'll get rattled around pretty hard, so it's got to be rather durable.

    Size: It must fit into the payload bay. 9V, D, C, and CR2032-size (large button) cells will not fit; AAs fit singly, a cluster of 3 AAAs can just fit, and 12V mini camera batteries work.

    Weight: Nothing over 6 oz.

    Animals: No thanks. I'm not allowed to carry anything with a backbone, and I'm not big on biology anyway.

    Cost: my budget is limited, but I can do anything under 60 bucks or so.

    Skill: I can solder, but not incredibly well, so basic kits or stuff on stripboard I can do; SMD not so much.

    Use: I'm not looking for an apogee sensor (like a Magnetic Apogee Detector, except if it can be integrated with a timer to calculate the time under the parachute and thus the altitude) or timer to control ejection of the parachute, but most anything else is game. Altimeters, directional finding transmitters, accelerometers, or spin rate sensors are good. Cameras are okay, but I doubt one can be find that's both that cheap and that small.

    Holes: Since this is a scale model, I'd prefer not to have any holes in the outside, but a hole up to a quarter inch in size for a barometric pressure sensor or photodiode is acceptable. The model also has four scale antennae about 4" in length; one could conceivably be hooked up as a real antenna for a directional finder system or datalink.

I'm currently looking at a small number of devices: 3 altimeters and one sonic finder (i.e, it beeps at 105Db every 5 seconds after landing until you turn it off). None, unfortunately, are kits, and the altimeters aren't cheap.

The first is the Quest 'How High' altimeter. It's cheap, small, and I can try testing it against other altimeters. It's not as advanced or quite as accurate as other altimeters, but it works.

The second is the Perfectflite ALT15K altimeter. It's expensive, but very advanced and has continuous data collection that can be downloaded to a computer.

The third is the Transolve P7 altimeter. It's similar to the ALT15K, although it only reads at peak.

Finally, I have the Transolve Micro TransBeep. It's a loud beeper that's useful for finding a medium-sized rocket in a large field.

I haven't yet found any plans or kits yet that I like. I'm especially looking for a way to take the input from a photodiode and hook it up to a counter to visually display the spin rate (or total spins) of the rocket on a seven-segment display.

Sorry that this is long and rambling and rather specific, but the fora are the best place I know for stuff like this.
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Re: Electronic Payloads for rockets

Postby the.coding.eye » Mon Jul 06, 2009 2:40 am UTC

Cool. Another rocket person on the fora.

I would recommend the PerfictFlite Alt15K Altimeter it is small and works great. When it comes to altimeters for rocketry, $75 is not really that expensive. PerfictFlite also makes another altimeter that connects with a computer to give you a altitude vs. time graph.

I looked at the kit you were considering from Apogee Rocketry and it only has altitude recommendations for up to G class motors. I have never built that particular kit, but if it just uses flimsy fin material such as balsa wood, you will need to reinforce it somehow. For a first time High Power Rocket flier I would recommend either getting a kit from http://www.publicmissiles.com (I certified Level-1 on their Black Brant VB) or the Talon 2 from http://www.giantleaprocketry.com. I have ordered from Giant Leap many times and their service is excellent. Their Talon 2 kit is not much more expensive than the Apogee kit and it has the Phenolic tubing preslotted for G-10 Fiberglass fins. It will handle any H or I class motor you can throw in it.

Another great website that has lots of rocketry related resources is http://www.rocketryonline.com. Be sure to check out their Info-Central site. It contains tons of info on design, building, electronics, and ground-support.

If you have any more rocketry questions just PM me.

- the.coding.eye (Level 1 HPR Cert)
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Re: Electronic Payloads for rockets

Postby The EGE » Mon Jul 06, 2009 6:28 am UTC

the.coding.eye wrote:Cool. Another rocket person on the fora.


We're a rare breed, eh?

the.coding.eye wrote:I would recommend the PerfictFlite Alt15K Altimeter it is small and works great. When it comes to altimeters for rocketry, $75 is not really that expensive. PerfictFlite also makes another altimeter that connects with a computer to give you a altitude vs. time graph.

I like the idea of using the Perfectflite, but it's pretty pricey. I'm pretty sure that it can be interfaced with a computer with an adapter kit.

the.coding.eye wrote:I looked at the kit you were considering from Apogee Rocketry and it only has altitude recommendations for up to G class motors. I have never built that particular kit, but if it just uses flimsy fin material such as balsa wood, you will need to reinforce it somehow. For a first time High Power Rocket flier I would recommend either getting a kit from http://www.publicmissiles.com (I certified Level-1 on their Black Brant VB) or the Talon 2 from http://www.giantleaprocketry.com. I have ordered from Giant Leap many times and their service is excellent. Their Talon 2 kit is not much more expensive than the Apogee kit and it has the Phenolic tubing preslotted for G-10 Fiberglass fins. It will handle any H or I class motor you can throw in it.


The Nike Apache has 1/8" 5-ply fins which are through-the-wall mounted and fairly small, so they're much stronger than balsa. It's built as a small high-power rocket, with steel shock cord mounts and a nylon chute. I contacted Tim Van Milligan and he said it'll do fine on H and even I motors.

the.coding.eye wrote:Another great website that has lots of rocketry related resources is http://www.rocketryonline.com. Be sure to check out their Info-Central site. It contains tons of info on design, building, electronics, and ground-support.


Thanks.
sillybear25 wrote:But it's NPH, so it's creepy in the best possible way.

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Re: Electronic Payloads for rockets

Postby BlackSails » Mon Jul 06, 2009 7:53 am UTC

How about an accelerometer? You could use it to work out the drag force on the rocket as it comes down.

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Re: Electronic Payloads for rockets

Postby the.coding.eye » Mon Jul 06, 2009 2:24 pm UTC

If you are interested in building your own altimeter this article might be of interest to you.
http://www.gwiz-partners.com/Flight_Computers.pdf
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Re: Electronic Payloads for rockets

Postby The EGE » Mon Jul 06, 2009 6:27 pm UTC

I'd like to try building an accelerometer, although I'm not sure exactly how to make one, or how to store the data. I've got a couple of 2K and 8K EEPROM chips but no idea how to use them.

I'm not really interested in a full flight computer, though. I like the ides of having full flight data, but since this is a single-stage, single-deployment rocket I don't need to control staging or ejection. I'm liking the look of that ALT15K altimeter a lot.

Unfortunately, a lot of this stuff is expensive. The 75-dollar altimeter is a week's salary for me (teenager with a part-time job), and the 130+ dollar flight computers are just out of my price range.

I'm trying to figure out how to build a spin rate sensor. I've got a range of photodiodes and CdS sensors. I figure I'll use something, Schmidt trigger maybe, to to make the output from it completely digital (facing the sun=1, facing away=0), then just feed that into something like a pair of 4026 counters, then into an LED display. I'd need some ejection sensor, though, even if it was as simple as the ejection charge burning a string and thus releasing a switch. I could also use one or two of my 4018s to divide the counter to figure out spin rate.

/internal monologue
sillybear25 wrote:But it's NPH, so it's creepy in the best possible way.

Shivahn wrote:I'm in your abstractions, burning your notions of masculinity.

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Re: Electronic Payloads for rockets

Postby EdgarJPublius » Wed Jul 08, 2009 8:31 pm UTC

I like the idea of using a radio direction finder on the rocket.

if you used the antenna to transmit some sort of radio beacon that could be triangulated on by a ground station, you could get a lot of information from the flight, and know where the rocket has landed afterwords.
that kind of set-up would likely be pricey though, but you might look into it.
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Re: Electronic Payloads for rockets

Postby the.coding.eye » Thu Jul 09, 2009 1:58 am UTC

Actually a radio direction finder is a great idea. Our club uses a Walston Retrieval System and it seems to work pretty good. However, as EdgarJPublius said, they are kinda pricey.
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Re: Electronic Payloads for rockets

Postby EdgarJPublius » Thu Jul 09, 2009 3:58 am UTC

Meteorswarm wrote:
EdgarJPublius wrote:I like the idea of using a radio direction finder on the rocket.

if you used the antenna to transmit some sort of radio beacon that could be triangulated on by a ground station, you could get a lot of information from the flight, and know where the rocket has landed afterwords.
that kind of set-up would likely be pricey though, but you might look into it.


Couldn't you get reflections of crazy atmospheric stuff that would make your calculations go to hell?


you'd have to be pretty high to run into much difficulty in that regard.

The Watson systems are cool, but not exactly what I had in mind.

For one thing, they're pretty high ranged, I doubt you'd need more than a mile, mile and half ground range (compared to 3-5 on the Watson units) unless you're using an I motor on a windy day.

What I was thinking was more along the lines of using three omnidirectional antennae hooked up to a laptop to continuously triangulate the rocket's position relative tot he antennae.

That way you get a map of the rocket's flight-path.

There are probably simple kits that are capable of this (though maybe not with enough range).

Writing it out like this, if you wanna sacrifice the locate your rocket's landing site aspect, you can get USB GPS dongles cheaply. Though I'm not sure if there are many out there with continuous logging capability when not hooked up to a computer, but it may be worth looking into if you wanna go that route.
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Re: Electronic Payloads for rockets

Postby The EGE » Mon Aug 10, 2009 1:50 am UTC

Sorry to necro my own thread, but my situation has actually changed. I found out that there's no way to put a payload bay in the Nike-Apache, and so I built it stock. However, I've decided to build a somewhat larger rocket for payload carrying. It'll be slightly under 3" in diameter inside, with a 24" long payload bay. Pretty much anything that can fit in a bay either 6,9,12,18,or 24" long is a go. I'm looking into small cameras / camcorders that will fit inside and be abe to take at least 10 minutes of video.

I've got several cameras that work that I can buy pretty cheap, so I'm fine on that account. I'm not really looking for any really complicated stuff like a radio direction finder or GPS logger, but something simple like a spin rate sensor or basic radio telemetry (i.e, nothing more than a cheap transistor radio for a receiver) would be good, as well as any non-biological experiments anyone can think up. Thanks.
sillybear25 wrote:But it's NPH, so it's creepy in the best possible way.

Shivahn wrote:I'm in your abstractions, burning your notions of masculinity.

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Re: Electronic Payloads for rockets

Postby Minerva » Tue Aug 11, 2009 8:00 am UTC

Here's a little something myself and some friends recently designed and built and are developing it. We haven't flown it yet.

http://www.practicalarduino.com/news/id/261
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Re: Electronic Payloads for rockets

Postby The EGE » Sun Aug 16, 2009 5:06 am UTC

Minerva wrote:Here's a little something myself and some friends recently designed and built and are developing it. We haven't flown it yet.

http://www.practicalarduino.com/news/id/261

That is absolutely awesome - a full electronics suite. Dare I ask how much it cost to build?
sillybear25 wrote:But it's NPH, so it's creepy in the best possible way.

Shivahn wrote:I'm in your abstractions, burning your notions of masculinity.

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Re: Electronic Payloads for rockets

Postby Minerva » Sun Aug 16, 2009 2:02 pm UTC

I'm not sure. Between a group of us, we had most of the stuff laying around.
...suffer from the computer disease that anybody who works with computers now knows about. It's a very serious disease and it interferes completely with the work. The trouble with computers is you play with them. They are so wonderful. - Richard Feynman

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Re: Electronic Payloads for rockets

Postby Talith » Sun Aug 16, 2009 2:12 pm UTC

Minerva wrote:I'm not sure. Between a group of us, we had most of the stuff laying around.

I wish i could say that about my friends :(.


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