Who needs chemistry when a little bit of physics will do? Instead of brewing up a batch of weak adhesive to make his own post-it notes, [Valentin] built this handheld device to add an electrostatic charge to bits of paper. Just give them a couple of seconds to charge and they’ll stick to the wall with ease.

The charging circuit is pretty simple, involving a transformer, transistor, resistor, and four diodes for rectification. He walks us through the build process, free forming the circuit using the transformer housing as a base. Once the circuit is fully assembled, a 9 volt battery connector is added and the fragile parts are hot-glued in place. It boosts the output voltage all the way up to 2 kV, but it’s still safe because it’s at a very low current.

The concept is akin to the high-voltage bulletin board seen last month. We wonder how long the notes will stay in place without an active electrical connection to keep the charge?

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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[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