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Topic: How many LEDs on each petal? (Read 1 time) previous topic - next topic

chocarrat

Hi, sorry for my bad English. I am thinking abaut a new lilypad proyect (using a lilypad USB). how many 40 mA leds can I Put in parallel in a petal? I want to make a lighting dress, with sound sensitive. could I put 4 or 5 LEDS. i will use a 3,7 LIPO batery (1200 mA) thanks

krazydarcy

Hi, according to teh specs for the Lillypad the current limit for each pin is 40ma. consulting my local electronics supplier catalog (Jaycar Electronics) most of the LED's in it have IF Typical(mA) as 20mA with vf(typical being anything from 2v to 3.5 depending on which LED you choose.  So you wouldn't be able to run more than two per I?O pin in parallel (not enough voltage to run in series.

If the LED was rated at 40mA however you can have only 1 per i/o pin.

Although it would be probably too much bulk, you could have the lillypad control something else that poweres the LED's
for example you can get LED matrix kits that you assemble yourself. instead of directly mounting the led's on the board, place wires that run to the actual LED's. however you will need a 5v<>3.3v logiv level converter along with a 5v supply for it as the Lillypad runs on 3.3v.

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