opengauge development: palm pilot technical issues
 

The palm pilot implementation has hit a snag. Superwaba closed the software gap, and serial communication with the 'duino is pretty solid, but I can't seem to find a solution that I like for running the palm without batteries.

One option is to make some "fake" AAA batteries, basically a foam or balsa plug with some leads to go to the arduino voltage supply. The only problem is that the palm will forget its programming if you leave it unpowered for a minute or so, and have to be resynched. So the user has to get everything in place, then pop out the batteries and pop in the power supply adapter in less than a minute.

The other issue is connecting to the pilot. It can be connected with a sacrificed cradle and a $1.50 plug to make a "null modem", but there should be a solution that allows reuse of the existing cradle, so the user doesn't have to locate a sacrificial cradle. Maybe a slide-in tray under the cradle could be fabricated. But then you have all this cable hanging around on your dashboard, or run it to nowhere. I think a box for the arduino with some terminals and a rs232 and power connection, then two small power leads wrapped around the cable to the fake batteries would be the tidiest. arduino goes under the dash wherever, and hooked up to an injector and a vss and battery voltage (possibly all by the ECU). The box can also house the vehicle interface circuits to keep it organized.

Then hotglue or velcro your hotsynch stand to the dash, or use a hotsynch cable and velcro on the back of the palm pilot.

Is this getting too hokey yet? :)

And the signal processor software is still in need of some work.

Reality check,
Comparison of the options (above base freeduino + vehicle interface circuits + software development)

2x16 lcd
Area: 1x6cm=6cmSq
Cost: $10+$3misc + $3 (buttons)
Difficulty: 7
hokeyness: 3

4x20 lcd
Area: 2.2x7.1cm=15.62cmSq
Cost: $20+$3misc + $3 (buttons)
Difficulty: 6 (easier to hide arduino behind)
hokeyness: 2

palm
Area: 5.5 x 5.5cm=30.25cmSq
Cost: $10+$5misc
Difficulty: 8 (have to program two devices and cobble multiple connections)
hokeyness: 6


the palm can display some large numbers though, but is a slow device and the original plan (OBDGauge) didn't prove viable, with my skill set anyway, so it is basically starting from scratch. I haven't sorted out the persistence yet, and hookup is a pain but it cant run on batteries very long with the serial port running.



I like the palm, but with a functioning guino board in hand (with LCD and buttons) it seems like the shorter and more straightforward route is to shelve the palm for now and focus on the guino. Unless that causes someone some serious heartache.

Sounds good to me. I don't have a palm to do and debugging with. :)

I do have 2 slightly older palms collecting dust if anyone changes their mind and wants them

I know I am late to the show, but did you consider using something like a Handspring Visor Prism? It is color, runs OBDGauge, and you can run it off a cigarette lighter plug in the vehicle... Where can I find a copy of this Superwaba?