If red LEDs are used, a 0.5 ohm, 5W led should be placed in series with the wire to the LED plate. The diagram shows 2 groups of 3 colors but can be easily changed for 2 colors. Or 3 sets of 6 LEDs for green/blue only (more effective) The arduino (or compatible) is hooked up to the LEDs via logic-level N-channel FETs. Use 2 sets of 6 LEDs for full tri-color (more versatile). The balancing resistors are about 1 ohm, but can be adjusted. The LEDs originally used are CREE Xlamp 7090 but any 1+ Watt LEDs work OK. Schematic and layout for LED plate in EagleCAD format.This is all public domain, so enjoy! * Schematic for LED plate in PNG format Power supply for testing, a ATX power supply is a good way to generate 5A+ at 5V.It was pricey at $40 but had the benefit of including a lead acid battery (which would have run almost $20 with shipping) and a basic lead acid charger. We repurposed a cheap yet enormous flashlight from Sears. 9V battery + holder with switch for the arduino, seperate supplies prevent noise issues when driving such large loads.A spare AMD processor heatsink and fan worked nicely and was free! 10 15 Minutes Easy Yes, you really can make a stunning dress with no sewing You’ll only need fabric, scissors, a measuring tape, and about 15 minutes of your time for this DIY no-sew dress. We used a 4A 6V SLA that came with the lantern 3 D cells or a lead acid is a good choice. Battery capable of sourcing 4A at 4V+.We used a DC boarduino and attached an FTDI cable to upload the firmware The AVR atmegax8 series such as found in the arduino is handy because it has 6 hardware PWMs. Nearly anything that can sink 2A is just fine. 6 N Channel logic level power MOSFETs.16 or 18 gauge wire for connecting things up.In theory a aluminum core LED is helpful but we found that for quick blasting, FR4 with copper fill worked just fine. 6" diameter LED plate, see the downloads page for layout.The internal resistance of the battery and Rds of the FET will make a difference, so do math and measurements! For red LEDs (and maybe green/blue depending on your power supply) you may need a choke resistor 0.5 ohm at 5W may be OK. Balancing resistors, one for each LED.( Like this, but make sure you get ones that match your LED) Go with narrow-beam lenses, about 20mm diameter. You'll also need lenses/optics for each LED.Look on eBay or other closeouts to get slightly-older LEDs for less. Or you can go with 18 each of green/blue for more effective dazzling. For color versatility you can use 12 each of red green and blue. there are 2 Watt LEDs that are now easily available. Take it more as a guideline (and use common sense) than a rigorous step-by-step! Parts list To make this project you'll need: This project isn't a kit (and won't ever be) so the instructions are more laissez-faire, with many opportunities for the maker to change elements or modify the design.
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