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Ozymandias

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Since I broke my Altacc 2C i've been brainstorming ideas for computers I would like to build. Let me know what you think.

Idea 1: (Somewhat expensive)

I just popped my last Altacc so I need to do something. I have wanted to design and build my own flight computer using a BASIC Stamp microcontroller for a while. My idea is to program the Stamp to sense launch and deploy the main and drogue parachutes via an interface board. I've come up with two ideas for user interface with my computer. I would like it to have an on-board LCD display with a detachable keypad. That would mean way more programming but I wouldn't have to take my expensive laptop out to the launch site. Parallax now makes a kit that allows you to use Bluetooth to wirelessly interface with the Stamp. That might be good for doing status checks once the rocket is sitting on the pad ready for launch. You could have the stamp check the continuity of the recovery pryos, battery voltage, etc. wirelessly from up to 300 feet away. My program would record and graph altitude, velocity, and acceleration. I could even make it compute Cd values!

Idea 2: (Very Expensive)

These micro ATX motherboards are getting so small these days. They are even small enough to fit in 6" body tube. This rig would only be suitable for very large birds but it would provide flight data aquisition, GPS location data, and real-time telemetry. I want to build a micro ATX computer with a 1.3ghz processor running Linux. I would connect the PC to an interface board to control recovery pryos, get GPS data from a reciever, etc. I could write a program to provide me with almost any data I could ever want (much easier said than done, of course). I could get telemetry data, status reports, and the like using an IEEE 802.11b network between my Powerbook G4 and the PC. Using remote login I could run processes on the PC over the network. I would have to use a flash card on the PC because the high G's would trash a conventional hard drive. After the flight, I could remove the drive and download the data for analysis.

What do you think? Any suggestions?
 
Originally posted by Ozymandias
Parallax now makes a kit that allows you to use Bluetooth to wirelessly interface with the Stamp. That might be good for doing status checks once the rocket is sitting on the pad ready for launch. You could have the stamp check the continuity of the recovery pryos, battery voltage, etc. wirelessly from up to 300 feet away.
BT is only 300ft if both devices have highpower radios I think. Otherwise it is only 30ft, maybe a bit more LoS.


These micro ATX motherboards are getting so small these days. They are even small enough to fit in 6" body tube.
They are so small that they fit on a DIMM these days.
Also USB Flash devices are now sufficiently capacious allowing a completely solid state storage for OS Apps and Data. No need for HD any more.
 
Originally posted by Ozymandias
Since I broke my Altacc 2C i've been brainstorming ideas for computers I would like to build. Let me know what you think.

What do you think? Any suggestions?

Main computer power on the ground on a cheap laptop, secondary/backup on board, R/C radio link, telemetry measurement sent downlink and servo signals sent uplink.

Laptop can run some minimal Linux install (muLinux, fits on and will run from 5 floppies; the entire distro on HD plus an archive of the entire distro plus all docs takes <30MB). We're talking 386 for a laptop if necessary.

Main control on the ground give you manual over ride. In fact it gives you manual primary control if you want. Onboard can take over if ground signal is lost.

Main on ground can give you real time read out of telemetry, which you'd want if you were using manual drive primary. It also gives you the ability to over ride the onboard should something go wrong upstairs. Using hybrids and they go wonky halfway up? Shut the off, force a separation, then force force first stage deployment when the numbers say it's safe. Maybe even real time video.

Scaling up? Just boost the R/C signal. R/C not good enough? Use a different transceiver ssytem with a different freq.

That's the system I want. Redundancy built in that includes both ends. Scalable up to making a space altitude shot using the same system (by then well tested) for 5000 AGL shots. Not most important to the rocket, but most important to me, is the ability to drive the rocket myself. There's another 'record' of sorts; fly the bird from countdown to touch down as a controlled unmanned vehicle.

Sure, power requirements would be hefty for a transmitter on board, especially if video was involved. Check out Sundance Solar's ultra-thin flexible film solar panels and figure square footage of rocket and so how much current it could generate.
 
www.gumstix.com


gumstix 200-f

processor Intel XScale® PXA255 - 200MHz
memory 64MB SDRAM standard (100 MHz bus)
4 MB Strataflash standard
(1) MMC slot for up to 256MB

operating environments u-boot - bootloader in flash
Linux kernel 2.6 in flash
busybox with webserver and remote login
fully open source
MMC/SD™ Slot hardware is configured for any MMC and SD™(*)
low power draws <250 mA at 400MHz without Bluetooth

dimensions 80mm x 20mm x 6.3mm - *Now Thinner!

power supply 3.4V - 5.2V takes Li-Ion, Li-Polymer, 3-NiMH, standard 4.5V or 5.0V inputs

power management circuitry on board
UART (3), I2C, USB Client, NSSP, PWM (2), AC97, LCD Controller, JTAG

$109, apparently in single quantity. For the metrically challenged, thats only about 3"x0.75" - about the same size as most altimeters.
 
While for some odd reason I really like the Kalman filter suggestion, my advice is to first figure out why you are killing altimeters before investing too much money and effort into a new one.

After you figure out the problem, stop doing that! :)

I have been using an AltAcc since 1999 and it has performed flawlessly. I did kill it last year as the result of a hard landing caused by an improperly rigged parachute. But it was repairable. A new 4 MHz ceramic resonator did the trick.
 
Originally posted by vcp
www.gumstix.com


gumstix 200-f

processor Intel XScale® PXA255 - 200MHz
memory 64MB SDRAM standard (100 MHz bus)
4 MB Strataflash standard
(1) MMC slot for up to 256MB

operating environments u-boot - bootloader in flash
Linux kernel 2.6 in flash
busybox with webserver and remote login
fully open source
MMC/SD™ Slot hardware is configured for any MMC and SD™(*)
low power draws <250 mA at 400MHz without Bluetooth

dimensions 80mm x 20mm x 6.3mm - *Now Thinner!

power supply 3.4V - 5.2V takes Li-Ion, Li-Polymer, 3-NiMH, standard 4.5V or 5.0V inputs

power management circuitry on board
UART (3), I2C, USB Client, NSSP, PWM (2), AC97, LCD Controller, JTAG

$109, apparently in single quantity. For the metrically challenged, thats only about 3"x0.75" - about the same size as most altimeters. [/B]

Hmm...hardware is getting to the point where we can add a CCD and a microphone and build a high-resolution, self-contained, compact digital video camera. Build a feature into the firmware to compress video into a buffer in RAM but not store it onto the memory card until a few seconds before launch detect.


Bill
 
Hardware is also getting to the point that before I was simply lost...now...I'm so confuseddddddddd !

So many recomendations, its difficult to know which is what without having a degree in dynamic electronics. 8)
 
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