For my physical computing art project, I have a 5x5x6 (that's a cube with a 5x5 matrix of LEDs on each side) array of LEDs. The LEDs are a strip, so essentially it uses SPI along a single data line to address the 150 LEDs. Now, my problem is powering the LEDs.
I have a 3.7v LiPo battery which I hooked up to a DC-DC Boost converter to output 5V. Previously I was testing just a 25 leds, and powering it through the 5V connection on the Arduino via USB, which works fine.
However, when I tried using the LiPo battery through the converter, the LEDs would power, but flickr randomly (and the DC-DC converter makes a hissing noise - capacitors?). I suspect this is due to the uneven current draw by the LEDs.
But, if I run the battery through the Arduino using VIN, and then use the 5V output from Arduino to power the LEDs, the LEDs work fine.
Also, although the LEDs are rated at 5V, they work (but also flicker) when connected to straight to the 3.7V battery.
Some facts: Each 5x5 panel draws about 350mA, and the DC-DC boost convertor
is rated up to 37V, and I think
it has a voltage regulator. The battery can output up to 2A, so I don't think it's a problem at this stage. I am just trying to power 50 LEDs at the moment. I am using the Arduino Uno.
My questions are,
- 1. What is the maximum current I can draw through the 5V output on the Arduino? (if it's high enough, then I might as well just use it!)
- 2. What is causing the flickering when powered through the DC-DC booster? Is it because of the voltage regulator? Would adding a 5V fixed voltage regulator to the output help, if this is the case?
- 3. Am I doing something fundamentally wrong with my set up?
And here's a video of the 5x5 prototype http://youtu.be/P78SCzkKxzY
for those interested!
Thanks for help in advance; this is my first time with electronics, let alone Arduino, so I will probably sound like a complete newbie. It is also likely that I've missed something that is completely 2nd nature to you, so please point out anything that would help.