20 Kilovolts Replaces Push Pins On This Bulletin Board

November 10, 2011 by Mike Szczys 89 Comments

Electrical Engineers don’t need push pins. That’s because they know how to control electrons! [Sven] put his knowledge of these subatomic particles to use when building his high voltage bulletin board. It uses a set of vertically strung wires to keep paper pinned against the board. The wires have high voltage at low current travelling through them. They’re in front of the board, but not touching it, and the board is serving as a ground plane. In this way an electrostatic charge pushes (or should that be pulls?) against the paper to keep each sheet right where he places it.

In the video after the break [Sven] gives us a tour of the hardware at work here. It starts with a 12V psu which feeds a buck converter. The regulated feed is patched into a high voltage supply which was designed as a CCFL driver. Finally, a voltage doubler is used to reach the final voltage, measuring about 20 kV per wire.

Don’t worry, [Sven] says the bare wire is “almost completely safe” because of the low current being conducted.

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Electrostatic Computer Interface

April 28, 2009 by Caleb Kraft 24 Comments

[vimeo=4366452]
[Justin] sent in his 1st place winning project from Northeastern’s Electrical Engineering Senior Design Capstone. It’s an interface that uses electrostatics to detect your hand position above it. As you can see in the video, it has decent resolution and can detect position on all 3 axes. When they uncover it, you can see the sensors arranged in a grid. They point out that each sensor isn’t just like a button, but rather detects a range of motion. They are using a pic 18×4550 to handle the sensors, which then communicates to the PC via USB. This could be pretty useful for musical performances as well as an alternative interface for people who can’t use a mouse.EO