Kinda off topic: "DIY" RC transmitter

I have a Walkera 2401 sitting around here. It has a basic CYRF module.
Is there any project to use that module in combination with an arduino to control spektrum receivers?
I.e. replace the control electronics with the arduino, which accepts the pot inputs from the sticks, maybe adds switches, and then outputs all of that directly to the CYRF module?
The module is a WK-2405-RF.
Failing that.. can a radio that has a trainer port transmit more channels than it can by itself?

This is something I've been thinking about a while now, I have so many old toy grade (but pretty nice) TX's that I've wanted to convert to run Devo on something like one of these.

www.ebay.com/itm/311248450407?_trksid=p2...e=STRK%3AMEBIDX%3AIT

The only issue I really see (other than getting the CYRF modules) is the display. I'm not sure if the LCD code in deviation FW could be changed easily (maybe to run something like an i2C OLED or something SPI or what) or if a display compatible with the current code would have to be sourced...

I also think it could be very interesting for many people!,
But the new diy board should be future ready, so more IO than you'll ever need and features such as audio out! I am happy to throw away my tx electronics and replace to a new board and hook upsome pots and switches.

The deviation display code has already been architectured to support multiple protocols. The newest round of Tx's added (the F7 and F12E) use a display size of "text". I'd certainly be tempted to start with that for a such a project.

I actually found a project that, while still a bit more complicated than I had intended, does exactly this.. arduino nano as the full controller board with PPM output.
www.reseau.org/arduinorc/

Yes but deviation has so much poweren potential in it, although it is not always straight forward to make mixes and create models it is very powerfull, going to such arduino platform is a complete downgrade.

What some are doing is generating a ppm stream with such arduino and send the extra channels to deviation as ppm, yes it works but I find it a bit of work around not very cleansolution.....
A good universal ARM board,with a display attached which has plenty of IO for pots and swithches,audio,buetooth etc = channels and we can do everything direct.
It would than be really open Tx project, not hack your devo tx, attract more users and developers.

...and is overkill for what I needed. I didn't want to build a great transmitter from scratch, I wanted to use what parts I have available without spending much extra.

Arakon wrote: ...and is overkill for what I needed. I didn't want to build a great transmitter from scratch, I wanted to use what parts I have available without spending much extra.

This is my thinking too. I'm looking to make little non-full feature radios, running deviation, that I can give to people I give BNF toys too (like my father in law who were giving a X5C to for Xmas or my best friend I gave a DIY 330 build to with a Orange 6ch rx). It doesn't need multiple protocols (and radios) and it doesn't need 12 channels or to have 88 protocols in memory... Just a $4 ARM board, an NRF (or whichever module I needed for that specific one) and a small display.


Another use I could see is having my camera on my AP rig be controlled by a second operator without needing a-whole-nother big $$$ transmitter just to control 2 axis, zoom and start/stop recording.

Arakon wrote: ...and is overkill for what I needed. I didn't want to build a great transmitter from scratch, I wanted to use what parts I have available without spending much extra.

What's "much extra"? Like cereal killer said, a 4 dollar arm board will get you the CPU in the 7e on a board similar to the arduino nano, just a fraction of an inch longer. Or you can go to $10 and get one on a discovery board, which is more like a uno with some extra hardware. Or go to $20 and get a discovery board with a cortex m4 instead of the m3m - 168MHz instead of 72, and over 80 io pins. Or go to $30 and get one with an lcd screen or that works with uno shields. Or go to $40 and get a Due. There may be other arm based Arduinos as well - I haven't been keeping up.

Sorry if I've gone on - I spent a fair chunk of last week evaluating hardware and software options for these things...

Or spend 0$ and use one of the nanos I have sitting around and get it done yesterday instead of having to order a board from china and work through a new setup and possibly not even find available code...
As it is, I have a working setup now that is just missing the transmitter module.
Thing is, I'm all for a DIY transmitter that "does it all".. but that wasn't the purpose of this.

Going with the parts bin is always a good idea, and why I order pro minis in six packs. But I do want to point out that the arm options I listed are all prices including shipping from us companies - except for the gum stick ones. Haven't found those from the us at reasonable prices yet.

I'm in europe, so the prices easily double or more when I don't order from HK.

Anyway if we go the super duper full featured lots of IO "ARM board" + Oled, etc even at 60euro, I am in to that! I am sure some crazy and creative radios will likley be build!

For a cheap simple tx, I save my (costly) time, even if i have the parts laying around.
I can understand if you like to tinker around it might be nice project, for me is reinventing a wheel, simple radios are very cheap readily available.

Where do you find a "very cheap" readily available Spektrum or FrSky compatible 8 channel transmitter?

A great display choice would be a cell phone you already have. A Bluetooth interface is around 6 bucks.

You don't need the display as much when you're flying. So just put it in your pocket ...

That would actually be fairly cool.. small app that would also take care of voice/sound warnings, so the actual transmitter controller only needs to send commands by serial port rather than actually process the voice playing etc.

I'm purposely reviving an old thread, because - well, I have new information that's relevant.

While looking into other things, I stumbled on the OpenTx DIY radio based on the Arduino Mega. Details here: www.rcgroups.com/forums/showpost.php?p=31630815&postcount=12

Now, for deviationTx, I wouldn't use the Arduino mega. It's got an under-powered Atmel processor (16MHz, 8bit cpu with 256K of flash) and is overpriced - at least for the original. The chinese close are cheaper. Personally, I'd go with the STM32F429Discovery board. It can be had for about $30 shipped, which is cheaper than the original but more expensive than the clones. But the CPU is a Cortex-M4, which is the same basic CPU as is used in the Devo Tx's. In this case, it's a 180Mhz, 32bit CPU with 256K of RAM, 2MB of flash and an additional 64MB of SD on dev board. There are cheaper variations of the STM32 discovery, including some with CPU closer to what's in the Devo12, but this is the only one that comes with an integrated LCD, which seems like a real win.

So, anyone interested in tackling this?

Wow thats indeed a nice board. loads of digital IO pin even stereo audio out,mems sensor.
Only for analog or ADC inputs is it enough or can it be muxed? lets say we liketo have 16ch analog pot

for 30 euro, what more can you wish?