LED's just for fun

I am building a plexi-glass enclosure for my electronics, and want to add some LED’s just for fun…
I want this kind of feeling:

Just want some ideas about how to “steal” current from motors or switches, etc. to give me some “electrical excitement” with LED’s and maybe a buzzer – Even if it is purely meaningless…


you could attach them to the stepper motor outputs on the gshield with the required resistor for current limiting. you may have to slightly adjust motor currents after you do this. you could also find the pin they use for step on the arduino and use a transistor off of that pin.

I understand that motive. One easy way is to cannibalize those candy dispensers and cheap toys found in check out lanes - especially at toys are us. They often contain LED’s on wheels that spin or LEDs that cycle through dozens of color and blinking combinations. Crack em open, take the components and go nuts.

Use a multimeter to see how much current each draws from its battery. Then use the appropriate current limiting resistor using this calculator: http://led.linear1.org/1led.wiz

Put in the voltage of the toy in the forward voltage box (1 battery = 1.5 volts; Coin cells will have the voltage printed on the case and will either be 1.5 or 3 volts, multiply the voltage by the number of your batteries), the reading from your multimedter in the forward current box and put 5volts in your source voltage box. If you don’t have a multimeter, you can bet those tiny LEDs probably only need 100 milliamps. Start with that figure to be safe. You can take the 5 volts from the Vin pad on your arduino - but NOT from one of the output pins (they can’t source much current), or just use a powered USB hub and take a USB cable, cut it and use the black and red wires (they provide 5 volts) just don’t draw more than 500 milliamps from it - especially if you are plugging directly in to a laptop.

Oh - and take pictures!

1 Like

not for nothing, but i have a breadboard in my “electronics box.”

This breadboard has 24volts on it to power the fan and protoneer shield. I am pretty sure i can hook up some meaningless LED’s that are just on, but I’m wanting them to blink or flicker or something…