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Topic: ShiftBar with LEDs - What volatge do I supply? (Read 962 times) previous topic - next topic

davivid

I have a few ShiftBars:
http://docs.macetech.com/doku.php/shiftbar

and some 5mm RGB common anode LEDS's
http://www.phenoptix.com/index.php/5mm-rgb-led-common-anode.html

The data sheet says they 20mA, so I will use 8 LED's per ShiftBar Channel = 160mA.

Therefore I assume I set the current control on the Shiftbar to minimum to allow the full 150mA available per channel.

But I am confused as to what supply voltage I connect to the ShifBars?

Grumpy_Mike

The web page says:-
Quote
The integrated voltage regulator powers the internal logic, allowing a single 5.5 to 17 volt supply rail to power the ShiftBar chain.

So as it has a built in regulator you can power it with any voltage in that range.

davivid

Oh right. thanks, I thought that meant for the logic chip and that there might be a separate amp circuit for the LEDS.

macegr

I think you will be disappointed if you connect all those LEDs in parallel. Some may burn out, and you'll see uneven brightnesses. You will need a separate resistor for every leg of every LED, and still, the current control features of the ShiftBar would not be used correctly. Usually the best way to connect a lot of discrete LEDs to a ShiftBar is to connect them in series with a higher voltage, but you can't do that with common-anode RGB LEDs.
Unique RGB LED Modules and Arduino shields: http://www.macetech.com/store

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