Hello,
I've just bought myself an 12v RGB LED strip with the hopes of being able t control it from my arduino. It turns out the the LED strip is a common cathode.
I barely had a grasp of how I was going to control it if it was common anode. I have very little knowledge of electronics and was just using this as a basic project.
Could anyone point me in the right direction of what I need to do to get this to work? Thanks
connect cathode to ground, wire anodes through proper circuity so the arduino can control it (but not take the load of it) and it should be a cakewalk
I'm very confused about how I'm meant to power the led's, yet be able to control the led's through PWM and not damage the arduino with the 12v power supply.
Could you possibly post a circuit diagram? When I try what I think is right, I dont have control over the LED's, they just light up
http://la.thepublicschool.org/class-notes/256
scroll down to "LED in a Circuit"
of course it will be a little backwards since you need to control the anodes but its the same idea
in your case it would be more like
which inverts the signal (ie when the arduino pin is on the led is off) but for your application it doesn't really matter that much
That circuit consumes more power when the LEDs are off (and depending on the forward voltage of the LEDs, much more).
If the strip contains its own series-resistors it is not suitable. A two transistor driver circuit is required since one can boost the voltage to 12V and the other provides the high-side switching. Or a zener diode and a transistor. A common anode strip would have been easier to interface.
You need something like this:-
Thanks for the diagram grumpy mike! You've been a lot of help in understanding how this works.
I'm getting the needed parts tomorrow and hopefully will be able to get it up and running.