Help with a real EGT indicator

[frazer]

If you take it apart it is is to tell which ones are the correct ones. Most of the pins are not even used. In the EGT's I have had just 4-6 pins were used. Remember the polarity must be correct as stated.

This one is really full of components and at least 8 pins are in use (2 for backlighting though), very compact and hard to tell which one does what. According to the website, it contains a lot of filters etc, which may explain the amount of components.

A wild idea of mine was to use a servo-card (opencockpits or phidghets) to get the voltage needed. If I connect the negative pin and the data-pin, i should get voltages near these. Anyone know exactly what voltages I would end up with? I think it's working with PWM from 0,4 to 25ms.

[jonesthesoftware]

Hi
You'll get 5 volts because PWM means PULSE WIDTH MODULATION which means the output switches between almost 0 and almost 5 volts with controlled width pulses. This series of pulses controls the servo motor by the duration and spacing of the pulses NOT the voltage. Make a voltage divider using a potentiometer and 1 series resistor (connected on the positive side of the pot) this is to ensure your voltage never gets too high when the pot is at the max of the stroke. Calculate this series resistor to give a maximum of say 200mVolts when the pot is at max, then you can control between 0 and 200 mVolts if you are testing for the thermocouple
regards
geoff