A project log for LED VEST

A vest loaded with 470 full color programmable led lights capable of playing video. Video Links Provided.

finchronicityfinchronicity 03/11/2014 at 00:259 Comments

Power is a challenge on this project. 

Idol current is 600 ma without turning any lights on. 

If they were all turned on the current could be up around the 14 amp mark.

The WS2812 LED's are really bright, and to make it look nice at night I have dialed back the max brightness to 50 out of 255. 

The upside is the plasma animation runs around 2 amps. 

The downside is that the resolution only has 50 steps as opposed to the full 255 steps at full brightness. 

This is making me want to talk to manufacturers to create a chip that uses the full 255 steps, but has a much lower light output for low brightness requirements, such as close range lighting like this vest. 

I have settles on a 12AH 6 Volt Lead Acid battery. 

A problem with this battery is charged voltage is 6.4 volts, which risks damaging the LED's and the Teensy controller. Thus I have installed a high current Diode to reduce the voltage back to the maximum 5.5 volts. 


LeoDJ wrote 02/21/2019 at 08:51 point

About talking to the manufacturer. Meanwhile, there already are addressable LED strips which implement global brightness different from the RGB color, eg. the APA102. The only difference is, that they are run from 5V, but so are many other addressable LED strips too.

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sean wrote 04/17/2014 at 07:03 point
You might also look into using 18650 cells for power. I used them for my tron-inspired LED suit which was (at steady white max power) 12V 10A. There are multiple protection circuits available which provide overcurrent, undervoltage, etc., at a range of voltages.

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Ben Delarre wrote 03/11/2014 at 06:34 point
You could try running the LEDs at lower voltage. You might be able to run them at 9v and get lower maximum brightness but your full 255 levels back.

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finchronicity wrote 03/11/2014 at 07:13 point
Yes, they are affected by the source voltage...however due to high current I want to avoid using a regulator. I dont want it generating any heat if possible, plus more points of failure...

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finchronicity wrote 03/11/2014 at 07:20 point
WS2812b's are 5v...but run ok down to about 3.5v

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Ben Delarre wrote 03/11/2014 at 22:18 point
Hmm fair point about reducing points of failure. But with a good high efficiency regulator you shouldn't be generating too much heat. Great work though man, looking forward to seeing it this year. You should be easy to find out on the Playa! ;-)

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risknc wrote 03/11/2014 at 01:23 point
I've been using these step down (buck) voltage regs from Pololu ( they're a bit spendy but have pretty awesome efficiency and power output (5v 7A per). Diode sounds interesting though, I'll look at that for future designs with the 2812's.

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finchronicity wrote 03/11/2014 at 07:15 point
I wanted to avoid using regulators at all...hence I went with a 6v battery. The diode does get hot though...about to try a bigger diode...

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finchronicity wrote 03/11/2014 at 07:19 point

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