Category Archives: Misc.

Breadboard Friendly DPDT Switch

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For the past week I’ve been trying to find a breadboard friendly DPDT switch to use on my Arduino Piano. After going through Digikey’s catalog a couple times, I realised that there just isn’t any DPDT switch that has the exact 0.1” spacing between pins on the same side, and the 0.3” spacing between the two sides in order to straddle across the gap on a breadboard. Therefore I decided to make my own breadboard friendly DPDT switch.

This DPDT switch I found on Digikey doesn’t have the exact 0.1” spacing, but it’s close enough to be used on a perfboard. We’ll also need two 3-pin headers, and a small piece of perfboard (protoboard, stripboard, whatever you like to call it).

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Cut the perfboard down to 4×3 and use a file to smooth out the sides. Then, if you’re not using a perfboard with individual copper pads, use a X-Acto knife to split the copper trace in the middle.2013-11-03_13.31.58Now you can solder on the switch first, and then the two 3-pin headers.

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LED Wristband v1.0

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Parts:

3528 SMD LED (Blue)    x    16

3.7v  300 mAh  Lipo Battery    x    1

SPDT Switch    x    1

JST-PH Connector    x    1

Wire and Heat Shrink Tubing

Possible improvements in the next version:

# More LEDs

# Smaller Lipo Battery (200 mAh)

# Smaller SPDT Switch (SMD)

LED Flasher

I made a simple LED flasher based on the schematic below. The only difference is that I used two 22kΩ resistors instead of 100k.

Parts list: LED x 2, 22kΩ x 2, 470Ω x 2, 10μF x 2, 2N3904 transistor x 2, SPDT switch x 1, 9V battery x 1.

t-flash2

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