Developing a universal module

I've brought this topic up several times over the last year, so I thought I'd start a thread dedicated to it in the hope that it'll lead to forward progress.

I want to design a universal module that can be used to run all protocols that Deviation can support. I'd like it to be low-cost and a drop-in replacement for the CYRF module on a Devo radio.

The goal would be to design a board tht can incorporate multiple transceiver chips with a single power-amplifier and single antenna. And to keep the overall production cost as low as possible.

The CYRF module includes the following pins:
5.5V supply
GND
SCK
MISO
MOSI
CSn
Reset

If we also use the Debug port, there are 2 additional IO lines available as well an a 3.3V supply.

Here's my thoughts on a parts list (prices are estimated at low quantities):
CC2500 QFN-20 package ~$3.35
CYRF6936 QFN-40 package ~$3.20
nrf24L01 QFN-20 package (no US supplier)
A7105 QFN-20 package $2.40
8:1 Switch for GPIO (something like a MAX4581) ~$2.00
3.3V converter (various options) ~$2.00
RF Switch. Something like a BGSF18DM20 looks pretty good, but I'm not sure about the impedence matching and using it as the input to the PA/LNA. ~$1.50 There seem to be pother options at the SP4T and SP6T levels as well
Power Amp ~20dBm. Several options around ~$1.00
A bunch of R/C/L components for impedance matching and biasing
Possible need for a small uC to to control the switches (AVR/PIC) ~$2.00

Virtually all of the above parts are SMT and cannot be reasonably hand soldered without special equpment. So this is not a 'kit' project.

I think I'd develop the above as a module that can directly replace the Devo module.

In order to make this module more attractive, it would be valuable to develop a PPM->SPI module around an STM32 MCU. This would host the Deviation protocol stack as well as some interface to control the protocol (perhaps bluetooth). Together with the above it could be used with any transmitter to provide all protocols. That is yet another project on top of the 1st.

I'll need to look at software options for development. While I ue a bunch of EDA tools at work, they are all proprietary and not designed for board-level development. I only do this kind of thing every couple years so I don't keep up with the current software much. In the past I used Eagle which works fine for small boards, but has the most atrocious user interface. If anyone knows what state-of-the-art in freely available circuit design and board layout software is I'd be interested.

Thanks, I'm aware there are lots of free solutions out there. I'm interested if anyone has actual experience with any of them. Spending effort to evaluate each of the options is not on my 'fun' list

It is more than a question of funding. There are potentially legal ramifications for monetizing an endeavor like this in the US. If I ever complete the process, it is very likely I would not be willing to actually be involved in the manufacture or distribution. There are also FCC regulations that come into play in the US and elsewhere.

So the best case is probably that I develop a BOM and a board design and make that freely available. That would leave it up to some entrepreneur to actually manufacture and sell the boards (as well as reap any profit). Becasue of the nature of the design, it is unlikely that this can be a DIY type of thing.

The alternative is to design a board that does not contain any RF, but instead just has solder pads for all known RF modules of interest. This board could be manufactured to use only through-hole components and could easily be sold as a DIY kit. The downside is that you will have a bunch of antennas to deal with, and overall a lot more expense (since modules tend to cost $10 to $15 each). The overall platform would likely be a lot larger as well.

That anytx module is pretty cool. That is exactly the kind of think I'd want to do. Looks like he's using my protocol stack (at least there's a mention of deviationTx in there). Add an RF switch, a couple more modules and and spi bypass, and that is what I described above.

The 7e has the proper pinout but is not pin compatible with the other devo radios.

The only way to make this compliant would be FCC testing, and even then that probably is not be since we could easily tromp on other Tx signal even if the power output is compliant.

All of the boards I have use either 0.1" headers or the 2mm headers and I have the pinouts for several of them. so designing a 'connecting board' would be pretty straight forward

Rogue, what do you do as far as solder masks go for your boards. do you make them yorself, order them, or just apply by hand?

What about ML2724 for Futaba FASST and CC2520 for JR DMSS?

I don't know how to source the ml2724. If you know of anywhere that can source them in quantities of 10 or less, I'm all ears. Adding the CC2520 is a good idea. I really wish it were possible to find a 2.4GHz transceiver with a flexible modulator. All of these chips are just barely outside the specs of each other such that they are incompatible.