Category Archives: capacitive sensing

DIY Capacitive Rotational Encoder on the Cheap with FR4

Rotary encoders are critical to many applications, even at the hobbyist level. While considering his own rotary encoding needs for upcoming projects, it occurred to [Jan Mrázek] to try making his own DIY capacitive rotary encoder. If successful, such an encoder could be cheap and very fast; it could also in part be made directly on a PCB.

The encoder design [Jan] settled on was to make a simple adjustable plate capacitor using PCB elements with transparent tape as the dielectric material. This was used as the timing element for a 555 timer in astable mode. A 555 in this …read more

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Posted in 555, capacitive sensing, capacitor, dielectric, diy, DIY capacitor, fr4, FR4 construction, hardware, high speed, misc hacks, pcb, rotary encoder, sensor | Leave a comment

Fail of the Week: Museum Buttons

Museum exhibits are difficult to make, and they’re always breaking down; especially the interactive ones. This is a combination of budget, building a one-off, and the incredibly harsh abuse they take from children.

My first exhibit is an interactive laser show that turns waveforms from music into laser patterns, and different types of music have very different patterns. I knew from talking to the museum staff that industrial buttons were a necessity, but it turns out that industrial buttons are made under the assumption that tiny creatures won’t be constantly mashing, twisting, and (ew ew ew) licking the buttons. After …read more

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Posted in capacitive sensing, children's museum, Fail of the Week, fotw, museum, photoresistor | Leave a comment