26 mai 2009

Very short howto build RCHv2

Withing few hours, provided you have the right components, you can build your own RC transmitter.

First, an important component is the transmission itself. Any module with PPM signal as input can be used. For its low cost, I choosed the Assan module (Hack version X8D) with Assan receivers. Cool price and so far works fine. It is powered with 5V.

The transmitter box is a very low cost transmitter such as those sold for RC simulator (FMS) http://www.flashrc.com/bmi/2637-gamepilot_boitier_simulateur_usb.html . Remove everything except the sticks and switches of course:

The micro processor is an Atmega 644 DIP, with the external crystal and 2*22nf condo. It must be flashed with the RCHv2 software:

Two small board are screwed in the plastic box, one for the micro-controller, the second one for the micro SDcard and the 5V power regulator. Do not forget the led also on the transmitter front.

One the right side, the UART plug to connect to the PC for the radio configuration (it's hidden on the picture between the protoboard):

Connect all the sticks, switches, the Assan module and SDcard board together:

And that's it, the last step will be to close the box and to configure the micro processor with the PC to set the mixers and settings:

9 commentaires:

Nick a dit…

Why did you give up on the xbee module and switch over to the pre-built ppm modules?

I am looking to do similar project to yours soon, but totally based on xbee PRO.

Olivier Bordes a dit…

Thanks for your comment.
No, I did not give up on Xbee as you said.
RCHome V2 still supports XBee (RCH & o24rcp protocols) and PPM (Assan currently).
The cost of Assan (80$ module + 2 receivers) currently is less than XBee, so why bother with XBee if retransmission back to the TX is not needed ?

Nick a dit…

My original plan was to use xbee pro connected via Funnel IO, using a Playstation controller for input on the ground. I just read this morning however that Playstation controllers lack the fine precision of a R/C joystick... May reconsider and do similar to what you have accomplishd here.

Funnel IO is like Arduino (uses same IDE) but has a xbee socket built in:

Anyhow... are you going to be sharing your software any time soon? I would be interested to see what kind of protocol you used to transmit the servo data from xbee to xbee. I plan to use 7 channels + some mixing for FPV flight. I am about to buy some parts today :D

Olivier Bordes a dit…
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Olivier Bordes a dit…

Drop me a mail with your mail address, and I'll send you code related to the transmission with XBEE. The overall code is not published yet , because it still lacks some features.

korp a dit…

This is a very nice project I am following with great interest. I am in need of a +6ch 2.4GHz transmitter, and I find the big brands way too expensive while low-cost chinese radios (Turborix, iMax, Eurgle, Hobbyking etc...) are too limited in the choice of receivers and extras. Assan really feels like a good way to go.

If I hadn't gone the PIC processor-path, I probably would have built this already from your instructions but with a small son I don't feel I have the time to get up to date on the AVR side too.

I'd be interested in looking at the hardware/electronics/design side of this but. You wouldn't happen to consider selling prototype kits for the electronics, or have the circuit schema in a understandable format like netlist, or maybe even as a KiCad project? I'd love to make a slim SMT PCB.

Olivier Bordes a dit…

Hi korp,
Right now there is no PCB /drawing for the electronic. Probably not for the V2. But it is still open for the next version which will be more complete (lcd, more analog inputs, switches, etc...).

korp a dit…

Olivier, is there no way I can convince you that publishing the schematic of v2 would be great? :-) I could send you a finished PCB, ready for soldering, as thanks.

Olivier Bordes a dit…

It needs to be discussed of course. Please contact me on my private email address, you will find it in my profile.