MPGuino+OBDuino in a single PCB?
 

Guys,

since the MPGuino is mature enough to have an optimized PCB for it but the OBDuino isn't that far either and potentially has a bigger market, why not designing a single PCB board with switches to select one or the other and and drive down the cost for both?

It could be done... the OBDuino with an ELM just add two ICs and a few components that could be not populated for the MPGuino version.
However the OBDuino with CAN interface only, does not use the same pinout for the LCD so it can be less easy to do.

Seems like the ELM327 now is a little cheaper (~$25). But would it be worth?

I still see it at 32.50$CAN+s/h, it does not make sense unless you want an OBDuino that will work on the 4 protocols in one unit. Else for ISO either the freescale or an ELM323 will work for less $$$, and a 320 for PWM and a 322 for VPW, and the MCP2515 for CAN, will all be cheaper.

iso can be done with a couple transistors, but the obd market is partly about keeping things simple, i.e. avoiding questions like "whats ISO?", and getting all sorts of values on just the one interface. But it is a whole lot of work just to get to universal protocol state from scratch, unless we build upon what Alex the allpro guy has put together or go with the 327 ($25US after conversion).

I could put a board together with all that (not much worse than the elm all protocols interface) and it might come out cheaper than the elm327. I should give Alex a note and see how much he wants just to use the hex file and relevant circuitry on our own board, just to see if it is worth the effort or not, he claims 327 compatibility. But who knows if the 327 vs the allpro actually works with more cars or not? With a custom circuit, we at least know how to support it and aren't left saying "sorry, this other thing we chose to use is broken". But as I said, it is a lot of work and needs to be coordinated to be of much use.

Maybe Alex is interested in selling some more of his allpro solutions. This means that they take some risks and maybe support the design (investment).

OBDuino does not use special AT command of the ELM327 but rather basic command so alex device should work, just plug the tx/rx of it on the rx/tx of an arduino and voilà, should work.
I don't know his license scheme, but as he provides schematic and HEX, you can build your own PCB, solder, flash the PIC, and use it without owning him something?!?

I'll ask him, can't hurt for a more production like effort. He'll put it on a chip and make a pcb for 6 bucks, can't imagine he'd be upset with accepting a buck or so for doing nothing :) unless we rope him into support of course.

But for DIY, I'd say you can just use it.