Yep, that's part of the evolving design...the other parts involve an 18F452 PIC, under-pcb mounting for Oncore GT or Trimble Sv6/AceII/AceIII GPS receivers, interfacing and battery backup for said receives, inclusion of a modified version of Bev Roadman's OBDII interface design (freediag compatible - although freediag will require ARM porting, and some modifications to make it suitable for the empeg display), and (this part is still to be 'evolved') support for some DACs/ADCs, and Dallas One-Wire support.

I was really hoping to put this all together as a kit for around $50 (not including the OBDII PIC/ connector that Bev sells), but at the moment I'm having assembly and volume issues. The main problem is that the most convenient technologies to do this stuff in are all SMD, which is not the easiest to solder by hand...eg the 3 big chips in this design (Quad UART, PIC, and RS232 driver) are best suited to either PLCC or TQFP packages. PLCC can be socketed, but SOT PLCC sockets aren't the easiest thing to solder either - basically they require reflow soldering. PTH PLCC sockets would be solderable by hand, but there'd be a lot of pins, 156 pins for those 3 chips alone, which I think is rather off-putting. Now if I knew that the volume would support it, then I'd consider getting either the sockets, or the chips themselves assembled onto the board commercially (pushing the price up obviously), and if I knew that this was only going to interest <20 people then I'd invest in a toaster oven and reflow the parts myself. The problem is the middle ground...

If anyone has any input to this, then please help! It will go much faster with multiple brains attacking the issues

For those electronics people out there, I'm using the free version of Eagle from www.cadsoft.de to create the schematic/board. I've had to create some library parts to support the design, and these should be sanity-checked. Let me know if you want to help with the circuit, although I'm going to be *very* busy until Monday, and I don't want to post the eagle files until I've cleaned them up a bit.

In the mean time, really useful specs for any would be PIC code writers out there will be the PIC18F452 (www.microchip.com), TI16C554 (www.ti.com).