View Single Post
Old 02-03-2017, 10:37 PM
luka's Avatar
Unregistered User

luka is offline
Join Date: Apr 2007
Location: Perth, Australia
Posts: 1,124
Hi Patrice,
Unfortunately the pulsing of the TEC is done as software loop with adjustable on/off switching and not as hardware PWM. I already had a look and it is not possible to convert it to hardware PWM as the pin B0 does not support PWM. So we are stuck with software on/off switching.

Now, while ATmega can probably handle the software switching frequency of 45Hz, I think that 45Hz is too low. The thermal stress on the TEC during the on/off switching is high and the PWM frequency should be faster than the TEC's thermal time constants. To avoid premature death most of places recommend PWM of at least 300Hz, some even suggest using between 5KHz to 40KHz.

Changing the timings of the loop is possible but it will have to wait because I don't even have a working cooling on my camera. Plenty of other things to fix at the moment
Reply With Quote