Helicopter Autopilot project thread

[rp181]

We are working on a helicopter autopilot, and chose XMOS to be the core of the platform due to the multi threaded nature. Jason sponsored our project, and provided some XS1-G4 Dev kits, so we can use them before designing a final board. I will be keeping a project log here, as well as on my website:
http://rp181.fortscribe.com/?cat=109

XCore project can be found here.


--May 30, 2010----
I found a camera module that I want to implement (for both wireless video and video processing for velocity and altitude calculation, and hopefully landmark recognition later on). The camera puts out both composite video, and video in the YUV format. I configured the I/O on a core of the XMOS for a 8 bit port, for the Y component. This gives me black and white video, another 8 bit port can be added for color. Right now the issue is timing to construct the image.
XMOS w/ camera and wireless modem connected:

External ADC breakout (24ld SOIC wide, 30 AWG wrapping wire):

Camera (a module from the CMU cam system):

System:

[jason]

Brilliant, great first post - thanks for posting that! Good to see you got the kits.

Please feel to create a new project if you haven't already: http://www.xcore.com/projects/ - you can give an official overview there etc then feel free to link in the description to this forum post and your blog etc if you wish to continue posting the updates to this thread if that is easier.

At least then people can have an official project to go to if this thread gets lost in the depths of the forum which can easily happen with the number of posts we get here.

[rp181]

I recieved a Century Swift 16 helicopter, but some parts need to be replaced (tail gear, landing gear, tail fin, blades are worn). This is much larger in person, I am not worrying about size as much now. The pictures have the 1W transmitter module for scale.
I designed a shield for the XMOS dev board to add the rest of the electronics. The board contains 2x ADC’s for both 3.3v and 5v devices, and 6 servo ports (A spare port can be used to add up to 6 more). The sensors are mounted on board, with two going off the edge for the correct axis.
I am restructuring the core usage, as shown.


Paper PCB mockup:

[jason]

Loving the images and the flow chart, great to see you are thinking in terms of multi-core.

[rp181]

Trying to get the Magnetometer to work. If anyone has information, I posted a help topic here:
http://xcore.com/forum/viewtopic.php?f=5&t=501

[otitov]

Very interesting shield! I would like to have one ;-) I hope it would be possible to use your shield to control cuadrocopters also.

Could you comment on transmitter/receiver model and specs?

[otitov]

Just read in your blog about 900 MHz 1 watt transmitter.

Do you need a special licence to use such power?

[lilltroll]

The 902 to 928 MHz is an ISM band.
The output limit without license is:

1) Maximum transmitter output power, fed into the antenna, is 30 dBm (1 watt).

2) Maximum Effective Isotropic Radiated Power (EIRP) is 36 dBm (4 watt).
You can obtain the EIRP by simply adding the transmit output power, in dBm, to the antenna gain in dBi (if there is loss in the cable feeding the antenna you may subtract that loss).

But the 900 band is not so simple anymore. It´s not allowed at all regions in the world. I'm no expert on RF but for an example wireless microphones could use both the Hi 800 MHz band or the 900 MHz band. But after some "rebanding" the 800 MHz microphones are not allowed at least in most countries anymore.

[otitov]

Thanks for clarification - I had in mind something about 50 mW (+17 dBm) (based on XBee-PRO DigiMesh 900 MHz module).

So the expected legal no licence limit is 1 watt. Very good.

I also heard that in USA with a valid radio amateur licence you have an access to other bands, something in 400-500 MHz range with even bigger power.

[leon_heller]

430 MHz or 70cm. I don't know about the US power limit, but it's 16dbW (39.8W) for 430-432 MHz and 26dbW (398W) for 432-434 MHz in the UK.