Given the increased time available to spend in our home labs for the next few weeks/months, I thought I’d share a project that I’ve been working on in my lab, which is a solder fume fan control circuit.
It may seem like a luxury, but a soldering fume extractor really makes the time spent with your iron a lot healthier and enjoyable. About four years ago I finally got tired of the smoker’s throat feeling that I’d get from an hour’s worth of inhaling flux fumes and decided to build one with stuff I had around the lab. Behold my creation!
Ok, so it’s just a 12V computer fan connected to a lead-acid battery via a toggle switch and strapped to a couple pieces of scrap wood, but it works. Rubber feet help hold it in place when the fan is on. Also, the metal grill which enforces the separation of fingers from the spinning fan blades is critically important!
The problem is that the fan is loud and interferes with listening to the radio or podcast while working. Turning the fan on and off each time I pick the iron is a pain, especially when I’m using two of the three hands I need. So the project this spring is to build a circuit which turns on the fan when the soldering iron is removed from the holder and off when it is placed back in the holder. Here are some design goals:
- No physical modification to the soldering iron itself (my Hakko FX-888 is perfect the way it is)
- Control circuit is powered from the 12V fan battery
- No software
That last one is in there because of personal preference. If you want to build one of these at home, feel free to design in a 1GHz Raspberry Pi.
I’m going to post more of my design and rational as time goes on. I’ve already prototyped a working circuit to use a temperature sensor (thermistor) to detect the presence of my iron. If you were designing this circuit, how would you do it?