Teensy 12v led strip only works at 6v

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andycomic

andycomic

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I have a weird problem. On the arduino mega my 12v strip works fine but when I try it on the Teensy3.1 it fails to work UNLESS I drop the led volts to 6v.

The leds have a separate Batt 12v supply. The Teensy has a seperate 3.7v supply OR I use the USB.

I've tried a resistor on the output pin incase it was a signal noise problem. Any ideas why the teensy would fail running a 12v strip ?

Thanks,
Andy
 
Hi,

In order to help, we're going to need a little more information. Namely:

-> Exactly what strip you're using (chipset, number of leds)
-> How it's wired up
-> Sketch you're using to test
 
Its WS2811, 200 leds, I can draw you a sketch later but basically its 2 batts, connected to each its devices (leds , teensy), sharing a common grn and the only other wire is teensy pin to led data input. Its all works perfect but just not on 12v. I am on a tight schedule with this project so I think I will ditch the teensy and stick with the arduino. I've used the teensy for many other led projects and they all work fine except this is the first 12v one i've done. Thanks for the reply though Cosford !!!

Andy
 
I would hazard a guess it's due to the 3.3v signal not being enough to register as a solid logic high on the WS2811. If they behave electrically similar to the WS2812B's, 0.7 x Vdd is required to register as logic high.

Best fix is a tri-state buffer, or you could hook up a transistor or mosfet circuit, just to step up the 3.3v signal to 5v.
 
So you mean at 12v the ws2811 doesnt register the small signal of the teensy ? That does make sense. I thought there would be lots of post already about this being an issue though.
 
Indeed, yeah. It depends on the electrical make-up of the strip though; how it utilises the 12v. But it would explain why it would work with an Arduino (assuming it's a 5v arduino?), but not a 3.3v Teensy.
 
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