Tagged Questions

-1
votes
0answers
44 views

power led to monitor plugged device

I am trying to create an experimental circuit to handle groups of HDDs (SATA) for multiple PCs. (e.g. I can swhich which PC control which group without having to move cables). The thing is, I would ...
3
votes
1answer
127 views

Higher current LED driver for persistence of vision display

Project needs We need an inexpensive LED driver IC that: Can source or sink at least 15mA/LED Has an SPI-like interface (not I2C) Has a separate latch pin Has at least 256 grayscale intensities ...
-4
votes
1answer
60 views

how do i power my LEDs [closed]

I am currently working on a display board for my church. It contains a static LED display built with light chaser technique and a moving dot matrix display. I am through with the last two but to ...
3
votes
1answer
299 views

How to stop a switched current affecting an IC?

I have 10 circuits each consisting of a Touch IC (Atmel at42qt1010) and electrode, and 2 x 350mA Constant current regulators (NSI50350AST3G) and LED's. All connected to a Arduino Mega, by ~1 meter ...
2
votes
2answers
136 views

Finding/Calculating LED light luminosity / power output

Is there a simple way to determine the light intensity / power output of an LED? e.g. Light output = current x F.Voltage - heat dissipation Light output = efficiency x current x F.Voltage I can't ...
2
votes
2answers
227 views

Keeping power to arduino after mains shutdown

I have had ideas for an arduino-controlled led-lamp for a while now. It's mostly fancypants stuff, but could be fun. The lamp is made up of several individually controllable leds. And on power-on I ...
1
vote
2answers
1k views

Using Multiple Power Supplies with RGB Leds and Arduino

I'm trying to control 3x 5m RGB LED strips using an Arduino Mega's PWM pins. Building off ladyada's tutorial: http://www.ladyada.net/products/rgbledstrip/. I created a 3x3 bank of N-channel mosfets, ...
2
votes
2answers
2k views

Analog circuit to turn on LED for 10 seconds just after power is applied?

Is it possible to use an analog circuit to turn an LED on for 10 seconds after 5v power is applied, then turn it off until power is removed and reapplied? This would be useful in small battery-powered ...
4
votes
1answer
581 views

Convert blinking (On/Off) power LED to fading

I couldn't come up with a better title...but here's the explanation. Basically, I need to create a small circuit for my PC to attach to the power LED. The way my motherboard works is that if the ...
0
votes
3answers
469 views

Issues with resistor heating, for an LED?

I am direly confused on this. I've used 220 Ohm resistors in the past for all of my LEDs (at least that I can remember), however nothing on my arduino+breadboard with a few leds on the 5V breadboard ...
2
votes
1answer
849 views

Fixing a flickering led

I own a Revo Blik radio that has developed a flaw: the display doesn't completely light up anymore when activating the device. When you're close by you can make out what it says, but not from a ...
0
votes
1answer
166 views

Harddisk LED Power Supply

I have a RAID card where someone in their infinite wisdom decided that only the cathode side of the individual drives' fault/activity LEDs would be provided on the board, and the other side of the ...
3
votes
2answers
323 views

Attaching electronics to a spinning surface without a battery

I am working with a friend to develop a spinning disk with LED lights on it. The issue we are having is wrapping our minds around the idea of electronics on a surface that is spinning. How do we ...
2
votes
2answers
455 views

Powering LEDs with a computer's power supply

I have 10 of these boards OctoBright CYANEA v2.0 connected in series, controlled by an Arduino. Powering one or two off of the Arduino 5v pin has worked for testing. Now I want to scale it up to 10x ...
3
votes
2answers
181 views

cable jacket melts

I am new to hardware. My breadboard just arrived and I am trying to light up my LED. I used computer power supply for power (red wire for + black for -) and used strands of LAN cable for connect LED ...
5
votes
5answers
762 views

Constant-Current for a 20W LED

Can someone explain "constant-current" circuits? When are they necessary? What happens without one? What's the simplest version of such a circuit? I bought some 20W LEDs off ebay intending to make ...
4
votes
5answers
422 views

Need comments and ideas for LED flashlight project

I'm thinking about making a simple LED flashlight. After doing some research, I think I'm going to use some 5 mm 12 Cd white LEDs with 3.6 V drop which can pass 20 mA. I'm not yet sure how much ...
4
votes
5answers
841 views

How to Determine a PCB's Power Requirements?

Disclaimer: I have very little (almost none, really) electronics experience. I purchased a set of IR illuminator boards off of eBay. The only information that the seller provided was that the board ...
5
votes
5answers
324 views

LED producting heat and best power supply

I was wanting to get a bulk lot of small LED lights similar to http://www.littlebirdelectronics.com/products/Basic-LED-%252d--5mm-Yellow.html I want to put them in balloons so that the balloons ...