[QUOTE=aaronsb;152673]Yep, thermocouples are calibrated with their lead resistance included as part of the sensor.
Something rather simple would be to use a linear analog converter, and a gauge with a selecting input that takes 5 volts. (the gauge linked below allows J & T thermocouple, RTD, Voltage, and mA)
Linearizing your thermocouple sensor makes a great fit with arduino style computers, since most of the DACs on those microcontrollers take a 3.3 or 5v analog signal converted to 10 bit digital.
Single Channel EGT Probe Amplifier Conditioner 0 to 5 VDC Analog Out
Mini Digital Pyrometer Gauge "SuperLite" with Peak Hold
You should also check out auber instruments, they have a lot of different components.
I think I will try to go arduino way. Arduino has lots of cheap and great sensors and other things like this MAX6675 Type K Thermocouple Temperature Sensor Module Interface:
MAX6675 Type K Thermocouple Temperature Sensor Module SPI Interface for Arduino | eBay
Yes you can buy gauges, sensor extension... you can buy the whole RV but everything has it's price...
Once I used Arduino successfully to build automatic torque converter lock for my Dodge Ram. It was fun to build, fun to program and fun to use. It was under $10 all together and it was working the way I liked.
Also using Arduino I can build water/methanol injection controller for next to nothing. The same Arduino chip can be used to read pyrometer and if needed it can activate multistage water/methanol injection to get more power and cool EGTs
This is the video to watch: