After all this time, it finally happened. I observed my Ventbot going through its paces as a natural reaction to my HVAC. Everything before this was just manual testing.

We've been having some crazy weather in the Seattle area. Last week, it was near 90F. This week, some days it is not getting up 60F. The smart thermostat controlling our heat pump keeps us in a comfort band of temperature. It's also integrated with Home Assistant so I can see when it's heating or cooling. This week, there is some heating.

On this complicated chart, there are several things. The solid orange blocks on the top half are when the heat pump is producing heat. The orange line is the temperature sensed in the vent cavity by the Ventbot. The blue(-ish) lines in the bottom half are the tachometer readings from three fans of the ventbot. (The timescale is too coarse to see the ramp-up and ramp-down for the fans.) The important part is that all of those things nicely match each other.

Yay! It works as designed.

The other nice thing is that I only noticed the sound of the Ventbot after I was already awakened by my alarm clock. It was audible but not loud, and it didn't wake me up. While I was listening and patting myself on the back, the HVAC reached the end of a heat interval and I heard the Ventbot go through its ramp-down.

"ventbot-red" is the only Ventbot I have installed. I have 4 more to go. They're all assembled and in their cases, and the fans are all arranged in their brackets. I just have to do the wiring for the BME280 temperature sensors and they'll be ready to place into vent cavities.