Identifying the Odd Electronic Component

If you ever come across an electronic component that looks like this (a small electrolytic capacitor or radial inductor) with simply the letters “HDX” and rattles if you shake it (even a little bit) then I’ll save you some trouble.  It’s called a “vibration switch”!  And, as you might guess, it’s a SPST switch that closes it’s contacts when it senses vibration.  These are not as sensitive as a G-Force sensor but they can do the trick in telling something when it’s being picked up or moved around.

IMG_1539

Power Supply

I needed a power supply that could give out enough peak current to power at least three Raspberry Pi 2s.  Just idle one Raspberry Pi 2 can draw almost 500 mA but at peak processing speed one can draw around 2 Amps at 5V.  I didn’t want to have to have three “wall warts” so I sat down and did some research on the internet and designed the circuit below.  With proper heat sinking on the 2N3055 power transistor it should allow for a peak of almost 7 Amps at 5V.

Powersupply