How to read a saw curve signal, with an analog input

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1

From a couple of Sony plasma screens, that I have had my hand on, I got these "SONY 1-680-078-11".

I thourght they where temperature sensors, since they where placed spread around on the inside, like to measure diffenrent parts of the system.

I have figured out how to hook them up to some power and I get this saw curved signal, that I can alter by applying heat to the transistor.

This is how it looks in my oscilloscope.

IMAG001.gif

When applying heat or cold to the transistor, the whole curve moves and the interval on each teeth stays the same.

Any good ideers on how to read this with an analog input?

I would like not to have to sample the whole curve and take the higest value. Since that would cost alot of CPU time.

 

This is a test for Birdmun, with a 1uF capasitor.

IMAG002.gif

2

I tried the 220uF and a 10K

I tried the 220uF and a 10K resistor and the wave action has smoothed out. Thanks Oddbot.

I turns out that these small boards are based on the LM35DZ heat sensor. I might try to detach one and build another circuit which makes more sense reading.

The fun of trying never stops. :slight_smile: