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pilotandy
Apr 09, 2006, 03:09 AM
Hi all. I stumbled on this site while doing research for my latest project idea. Here's the plan. Any input or advice would be much appreciated.

The UAV will NOT be a standard heli, but instead be a 4-motor craft similiar to the x-ufo or dragonfly V.

For sensors I intend to use:

(3) ADXRS300 gyros from Analog Devices
(1) 3-axis ADXL330 accelerometer from Analog Devices
(1) 3-axis HMC1053 magnetoresistive sensor from Honeywell
(1) WD-G-ZX4120 GPS module from Futurlec

I'm currently trying to figure out if I can get away without buying the gyros. Three of them will cost about $120 us. The datasheet for the accelerometers on the Analog Devices website has a diagram and equations to use a 2-axis accelerometer as a tilt sensor. This works because the accelerometers can detect 1g of acceleration in the downwards direction. The only downside is that the values will not be correct when the craft is accelerating, but this can *maybe* be fixed with a data filter of some sort.

If I do end up using the gyros, the accelerometers can be used to correct the gyro drift.

The magnetoresistive sensors will be used in combination with the accelerometer data to create a tilt compensated digital compass.

And finally, the GPS module will obviously be used for navigation data.

The brains of the UAV will likely be one of Atmel's ATMega processors. They have up to 8 built in AD converters for sensor inputs, and up to 6 PWM outputs for servo control. I would most likely use 2 outputs for pan/tilt camera servos and the other 4 to drive the brushless ESCs.

Anyway, I know that's a lot to digest. I'm curious to hear what ya'll think. I know it's an ambitious project. I've got a CNC machine at my disposal for milling PCBs and other parts. I intend to model everything up in Solidworks before I start the build.

If anyone else is interested in joining in I'd be more than happy to work with a partner or team. I live in southern california, but that doesn't exclude anyone who doesn't.

AntonK
Apr 09, 2006, 02:31 PM
Pilotandy,
Might I suggest you come talk with Antoine and myself in paparazzi's IRC channel. This is something the paparazzi team has been working on, and you may find some of the information you are looking for.

Anton

Tuner
Apr 10, 2006, 01:29 PM
I am going to be attempting the same thing.

Their 4 rotor looks very nice.
I have seen another 4 rotor project where the fellow built his speed controllers and his entire flight computer & gyros from scratch.

I am trying to get free time to dive into the paparazzi project and get started my linux skills are nonexistent. I feel it has the most potential of all the opensource projects.

Scott

pilotandy
Apr 21, 2006, 04:58 AM
A quick update. A box of goodies arrived today from Analog Devices!

I now have 3 gyros mounted on 20-pin dip eval boards and a dual-axis accelerometer eval board. I wired them up and did a bit of testing with no problems.

I've poked around a bit more and looked at the paparazzi and RCAP projects. They look cool and a lot of the information on the sites will be useful for this project.

I've been looking at motors and controllers. I've found a very economical esc/bldc combo on ebay that looks promising. I was hoping some of you could provide some feedback.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6047461452&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

copperclad
Apr 21, 2006, 06:29 AM
hi andy
i don't see a listing of the KV for that motor , dana :)

pilotandy
Apr 21, 2006, 01:36 PM
Based on other auctions I'm thinking it's a 1750KV. Maybe someone else can confirm this...

avernix
Jun 18, 2008, 12:26 PM
Have you guys gotten anywhere with this?