View Full Version : Water cooler for my laser, need to halve temp sensor output voltage :(

08-20-2013, 06:50 PM

Teensy 3.0, temp sensor outputs 2.35v to 3.85v which is outside 3.3v ref:(
I can't use a higher vref can I? Could I half the voltage of the sensors output? I tried everything I could think of, its a little beyond my electronics level atm.

Setup as the "calibrated sensor diagram" from there datasheet http://www.jaycar.com.au/products_uploaded/ZL3336.pdf

50w co2 laser for cnc should arrive very soon, Hooking it up with some Peltier's to lower its coolant below ambient.

I'll post pics if I get some help ^_^

08-20-2013, 07:24 PM
A resistor voltage divider will do the trick, two resistors of equal value will half the voltage output.

On the other hand if this is beyond your electronics level do read up a bit or you will hurt the laser,
your self or someone close by.


08-21-2013, 04:03 AM
Yes I know enough to get by normally, I just don't understand how diodes work well enough or I'm just been daft....

I know if I add 2 resistors between the output and ground it will affect the reading, so half of that reading would be wrong. I could work out how to half a single reading, but that's not going to help me.
I'm just not sure how to get half the output without affecting it's original value. Or I'm thinking about it all wrong...

The LM335 with a trim pot to calibrate it to 25 degree's
How do I half the output which ranges from 2.35v-3.38v


08-21-2013, 06:09 AM
O durrr... I was just using too small resistors to devide the output pulling down R1... using 2 20k's and its working fine ;-)