heinzboehmer's 2002 Topaz 6MT Coupe

[Obioban]

3D printer has been the greatest addition to my capability set of anything I can remember. I regret not doing it years ago.

It's pretty much been continuously running since I finished building it. Every freaking project benefits from it somehow. As your project above :P

[heinzboehmer]

3D printer has been the greatest addition to my capability set of anything I can remember. I regret not doing it years ago.

It's pretty much been continuously running since I finished building it. Every freaking project benefits from it somehow. As your project above :P

Completely agree, I use for most projects as well.

[ac427]

Small side project motivated by a comment from karter16: https://nam3forum.com/forums/forum/m...983#post322983

I did notice some weirdness with the ADC on Gauge.S. On a multimeter, the analog output from the AD8495 is rock solid and matches the expected temp (tested with boiling water). On Gauge.S, the voltage readings are offset by 27 mV and they seem to jump around. Annoying, but the offset is easy to fix and I guess I'll just have to deal with the noise.

Just waiting for more wire to arrive in the mail and then I can build a quick harness for thermocouple power and data.

Have you asked Sorek about the Gauge.S readings randomness?

[heinzboehmer]

Have you asked Sorek about the Gauge.S readings randomness?

I have not, but i probably should. I just didn't want to get sucked into another long saga of trying to debug closed source firmware, like what happened with D bus init on the V5 board.

Will reevaluate when all four thermocouples are set up and I've logged some data.

[ac427]

I have not, but i probably should. I just didn't want to get sucked into another long saga of trying to debug closed source firmware, like what happened with D bus init on the V5 board.

Will reevaluate when all four thermocouples are set up and I've logged some data.

I know what you mean about getting embroiled in that sort of misery. Maybe just let them know and leave the with it.

[heinzboehmer]

Thermocouple wiring complete.

Decided on a harness with three "steps":

1. Gauge.S pigtail since getting 3.3V from the board involved soldering to it.
2. Loong harness for each thermocouple.
3. Small "manifold" harness to go between (1) and (2), that feeds 3.3V and GND to the thermocouples and also routes their outputs correctly back to the Gauge.S inputs.

I did make a rookie mistake and only ordered three wire colors. Should have ordered more so that each thermocouple output was easy to identify, but too late. I'll make some labels and attach them to each one before putting them in the car.

Everything seems good electrically, but you can see the weirdness in the ADC quite clearly:



Each thermocouple assembly measures in at 3.2m from tip to connector. Made them long so that they can reach all four brake calipers, in case I ever want to log detailed caliper temps.

Also, slope of the output on the AD8495 works out to be 5mV per deg C, so I'm betting the voltage drop from the long harnesses is messing with the calibration. No big deal, can always boil more water and change the offsets in the Gauge.S config.

Next up is routing everything to the engine bay and I can finally get data on the E86 brace windshield mount.