Pulse Mode vs Voltage Mode. Can someone break it down for me?

Dusty Hicks

New member
I have the HM 4.3 with R-Pi 3b+. I'm having trouble wrapping my head around which mode i should choose for myheatermeter. It appears the wiki seems to suggest that maybe only the 4.2 can handle voltage mode, and therefore the 4.3 should be put in Pulse mode?

From the wiki: "Voltage mode is available on HeaterMeter v4.2 hardware and enables step-down circuitry to produce a constant voltage on the output pin between 5V and 12.1V. Voltage mode is more precise with a linear output curve, and runs the blower more quietly than pulse mode. Attempting to use voltage mode on hardware without support for it will result in the blower turning on and off randomly!"

I'm just wondering which setting to pick basically for all my smoking, if someone can explain which is better in layman's terms, I'd be appreciative of that.



Pulse Mode, or Pulse-Width-Modulation (PWM) runs your fan at 12V, but at a certain duty cycle (%on/off) so the fan sees a perceived voltage. Voltage mode is the way to go. Not sure where the notion that Voltage Mode will not work on the 4.3 version. There's really no difference between 4.2 and 4.3 other than the layouts of the boards and some small voltage (5V/3V) differences. The blower driver circuit is the same.

Here's a short video on how PWM works ...https://www.youtube.com/watch?v=YmPziPfaByw

Short answer, use Voltage Mode.
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