Paparazzi build thread

[sesat]

Hello everybody. After a long time reading up and making preparations, I am going to get started implementing the Paparazzi UAV project from http://www.nongnu.org/paparazzi/

I will not utilize any autonomous functionality on it, just the flight-stabilization functions. I am going to do this in progressive iterations because I'm well in over my head, my area is Economics not EE.

I'll list all my progress here. You are all welcome to join me, and are invited to 'get in' on my PCB orders etc.


Ram.

[sesat]

For those unfamiliar with the project, the system runs in three modes.

0 - aircraft controlled by r/c transmitter
1 - aircraft controlled by r/c tx with hands-off flight stabilization.
2 - waypoint-to-waypoint autonomy

Essentially, my goal is to implement FMA Co-Pilot like flight stabilization with the added feature of altitude hold. I wish to add the feature of taking notes whenever I take a photograph with a on-board camera, noting things like location (lat long alt) and attitude.

The system is made up of several major components:
R/C receiver
Mega8 (master control switching, ppm decoding from rx, servo driving)
Mega128 (medium level logic, flight stabilization)
Infra-red thermopiles (horizon sensing)
GPS receiver


Low level and medium level logic are separated between the Mega8 and the Mega128 for safety reasons. Software on the Mega128 is far more complex than that of the Mega8 and in the event the microcontroller goes silly, the user still can control the aircraft through the Mega8.

Even higher level logic should be reserved for another dedicated processor, like a JStamp or a Gumstix. Significant autonomy can be programmed into that, like say an AP control logic that lets the user define the area needed to be photographed and the detail needed, and the system will guide the plane to canvass the entire area and take successions of photgraphs. I'm not planning to implement any such features in my first attempt at this project.

I'm deciding on how to tackle my first attempt. Either I will be stringing the components together with a perfboard, or have a cheap PCB made. (cheap = FR4 epoxy/glass, 1oz copper, 1/16" thick.)


Ram

[sesat]

The CMX modem has to go. What a waste of all-up-weight and boardspace. Modulate the serial data from the microcontroller, and send it through a voice channel on a 2.4Ghz downlink? Unncessary double conversion, only forgivable if you've got a a/v downlink already.

I'd like to use a bi-directional link. Maxstream 9Xtreme sounds good, but maybe I'll consider a Class 1 Bluetooth transeiver if I need more data bandwidth than range.

This requires me to alter the 1.2.1 board schematic. I'm going to have to go around campus looking for a EE student to help me. It looks more and more like I'm going to have to start with a perfboard.


Regards,
Ram.

[sesat]

The Mega8 is available in DIP form.
The Mega128 can be optained premounted on a circuit board from Olimex, with .1" pins tied to all 64 leads on the SMD uc.

The mating header for a Maxstream 9Xtream are .1" pitch. The mating header for a 9Xtend is a Molex Milli-Grid 2.0mm.

Olimex mounted Mega128 available from http://www.sparkfun.com/shop/index.php?itemid=157&

The p/n for the MilliGrid on the Maxstream Knowledge-Base is obsolete. Use Molex 79107-0009.

The p/n for the Molex 1.25mm pitch connectors for the rest of the Paparazzi board are the Molex 53048 series for the right angle version.

Ideally we want right angle connectors at the PCB edge, we're stuck with verticals for the rest.

All part numbers are for through-hole not smd versions! I may need to use a SMD part for the modem though, to minimize changes to the existing schematic.

Actual part numbers I'm using coming up. Mouser has what I want.


Ram.