Fume extractor on a boom-arm
After all these years of soldering without a fume extractor I decided to quit a bad habit and build one. My parts bin is, of course, full of fans so I got a 120mm one and got to work.
Design-wise the course I took was to use a lamp boom/arm and mount the fan on that, so it could be positioned as close to, or over the soldering job.
Half an hour of solidworks later, I had 3 laser cut parts. Two grills and a spacer consisting of 5 and 3mm acrylic to get to and 8mm space to accomodate 2 sheets of filter material. With the filter I went the only way I knew which was using an activated charcoal foam sheet which is sold for exhaust hoods. So I cut it out in the shape of the spacers.
Then I just dismantled the cheapest boom-arm lamp I could find and mounted the fan onto that. Of course it took me three tries to get the holes right. Tired, I guess.
All assembled, and waiting for a speed controller:
On to the speed controller. I briefly thought about using an Arduino to provide the PWM for the 4 wire fan I used, but then I realized I hadn’t used a really old friend in a long time. My good old buddy, the 555 timer. I found a schematic online to provide the high frequency PWM for 4 fire fans and built the schematic on a small perfboard after trying it out on the breadboard first. This way, I didn’t need any voltage regulators and I saved loads of space.
I’ve fallen in love with this lamp arm. It’s so cheap (around 5 euro) and versatile! I also built a microphone adapter for it, for a friend of mine.