Tagged Questions

1
vote
1answer
77 views

Interactive Single Color LED Matrix

I'm trying to build an LED matrix (32x16) that lights up in certain areas in response to movement, as detected by another matrix (8x16) of infrared phototransistors. Here's where I'm at: Main ...
4
votes
2answers
292 views

Small, cheap, and simple driver for 16 RGB LEDs

I am working on a board design that will put 16 RGB LEDs in a circle around a rotary encoder. I want this setup to be simple so that I can run it from any micro with limited software (ie. built in PWM ...
4
votes
2answers
184 views

How do I pick a surface mount LED?

I need a red and a yello LED indicator in my battery operated project. I am looking at specs on Digikey and they list brightness as mcd, viewing angle and test current. Viewing angle I know, but how ...
4
votes
4answers
536 views

How to hack a walkie-talkie to light up LEDs when it receives a signal

Rookie circuit-bending question: I am trying to hack a walkie-talkie to light up some LEDs when it receives a signal. I figured the easiest thing to do would be to have the LEDs light in relation to ...
2
votes
2answers
605 views

I want to build an interactive LED Table. What are my options for a controller?

I have seen a couple of videos and instructables where people have created a matrix of LEDs controlled by photodiodes/photoresistors inside coffee tables, so that when you put your hand over the table ...
9
votes
7answers
2k views

LEDs on a (battery) budget! – How can I lower the current through a LED without using up the battery?

EDIT: Here is a much brief version, the meandering motivated version is probably subsumed in the parent question on general battery life optimizations. How can I lower the current into a LED ...