Moving air with spinning blades is the most popular way, but it is not the only way. Using the PCB actuator technology he has been working on for the past few years, [Carl Bugeja] built a small electromagnetic flapping fan using a custom flexible PCB.

Inspired by expensive piezoelectric fans ($400 for a 30mW fan), [Carl] wanted to see if a cheaper alternative could be made. Using a similar design to his other PCB actuators, he had a custom flexible PCB made with an integrated coil, which can flex on two thin supports. These supports also contain the power traces for the coil. By sticking the base of the PCB between two neodymium magnets, it can flap back and forth when driven by an alternating current. It produces a bit of airflow, but nearly enough to be useful. The power traces in the thin supports also break after an extended period of 180° flapping.

Although this probably won’t be a viable replacement for a rotary fan, it would be interesting to see how far one can push this approach by optimizing the design and magnet arrangement.

[Carl] has been experimenting with a variety of applications for his PCB actuators, from tiny flopping robots to tiny speakers, he doesn’t seem to be running out of ideas. A flip-dot display might be interesting…

I already have Flip-Dot display arrays which contain the coil in the PCB…

Do you have any details? Perusing your site i don’t see it as a project so are you just talking about some product you bought?

Back in the 80’s, there was an upgrade for the Macintosh Plus that came with a two-blade (two separate single units in a package) that were piezoelectric. It connected to the 120V 60 Hz AC line inside the case.

It didn’t move a lot of air, but it was quiet!

Make for a good chip-set fan.

We used one on an Osborne I and it still works. It clipped on the outside of the computer; you’d have to remove it to pack up for travel.

Neat put it on a boat or even better use it as insect wings.

Kinda like the MaxChill fans for the original Macintosh Plus, circa 1987.

Apple’s ascetic aesthetic bit them in the backside when they elected to omit the fan in that device. If you ever upgraded the memory or even ran the thing in a warm room they would overheat. The MaxChill piezo fan was bundled with $ome memory upgrade$ so to keep the quiet charm undisturbed.

Us cheap slobs just banged a muffin fan in and called it a day. (not that that machine could ever be called ‘cheap’)

Yes! That’s what I was referring to… just couldn’t remember the name!

This would be brilliant for a bristlebot!

$400 for a piezofan? I bought a couple of them in the 90s just to play with. Maybe $20. I should have kept them in the safe.

Hey, where’s the rest of the comments gone?

More like 6Eur: https://www.buerklin.com/de/Piezof%C3%A4cher-UPF-76Q-Piezof%C3%A4cher-127%C2%A0mm/p/65B744

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