Today is our local election day for most of the cities in Indonesia. It is also declared as a public holiday. Yesterday I prepared for a long night for coding. But I was always having troubles typing in the dark while my wife and kids are sleeping. My fingers can't remember the position of symbols and numbers well.
Fancy USB Light is sold around $5 each or $2-$3 for bulk buying. Searching around I found stuffs needed to start this simple project to accompany me at night.
Step 1: The Leftovers
All founded in my treasure boxes were :
- USB male plug.
- Short ethernet cable.
- A white LED.
- A 110 ohm resistor (or any value between 100-120).
- Soldering iron.
- Wire Cutter.
- Electrical tape.
Step 2: Simple Wiring
If you happen to have four cables comes out from your USB, just cut off the white and green cables. Those are data cables. We only need red (5V) and black (Ground) to power the LED.
Connect red (5V) cable to LED's anode, normally a smaller piece inside the LED if you have transparent one. And connect black (Ground) cable to LED's cathode, normally larger piece inside the LED, or marked with flat edge on its shoulder. Resistor can be connected to either the anode or cathode (the resistor's color code below is not representing the one we use in this project).
Well, I use some heat shrink tube to avoid short-circuit. You can simply use electrical tape instead. Then I wrapped it with those colorful wires inside ethernet cable. Why ethernet cable? Because it has eight single-stranded cables inside, which are strong enough to hold the bending shape we wanted.
Step 3: Testing
You know what? My LED is not illuminating. Then I found that I read the wrong colors. I was calculating brown-brown-black-black-brown to be 110 ohm 1% before I noticed the thick brown should be read last. So I was using brown-black-black-brown-brown and that is 1K ohm 1% ( >_< )
Replacing it with brown-black-brown-silver (100 ohm 10%) it was then shining.
I cut small piece of ethernet cable's jacket to cover half of the led to prevent blinding white led when I am using it in a dark room. I wrapped the whole cables with electrical tape and the ethernet cables are shaping a DNA style which I think it is cool. If you don't think so, you can just wrap them all with ethernet cable's jacket before using electrical tape.
Simply plug it on your power bank for a test. There you go.. Harry Potter's Magic Wand :D
Now this is what I need for a long long ... night. Plus a cup of coffee ... ah...