Another simple tool I went far too long without. Like many things I do myself, I do it to save money and put this together with things I had readily available. The fan is from an old unused server, the rubber feet are normally used for vibration dampening hard drives in PC cases, the input power jack is a 1/4″ TRS adapter, and the base is some aluminum L channel I cut with a hack saw and filed smooth.
The fan control circuit is an NMOS as a voltage-follower and a 10k pot to set the voltage. It’s not very energy efficient but it’s quick and dead simple.
I experimented with carbon filters as well, testing it with a sheet of carbon filter mesh normally used for small composting containers. I found it reduced the airflow too much and even with the filter in place I could see smoke passing right through the fan so I opted to leave them out.
