Ambilight first led lit all the time, help?

Yesterday I got WS2801 led stripe and tried to make ambilight.
I connected stripe (86 leds) to the external power supply (5v 2a) and to the 19 and 23 gpio pins as in lots of tutorials.
Installed hyperion, set up number of leds and offset and sent config to pi.
Then I started hyperion and the rainbow appeared. But then…
Colors seem to light up randomly, cannot set solid color on the color wheel and when I stop hyperion, all leds go off except the first one, which is solid white and flickers from time to time.
When I cut off the first led, second led became first and started acting the same. Replaced first stripe of 27 leds with another one - same thing.
So it must be something with hyperion config i think…
Could you help me? This thing is driving me mad all night :slight_smile:

You need to connect the ground wire of the external powersupply to the ground of the pi.

Edit: 2A is not really enough for 86 leds!

86 x 0.06A (full white) means 5.2 A.
With a safety margin I would suggest a 6 or 8A supply for the leds.

And you probably need a level shifter.

The leds want a signal level that is higher than the 3.3v you get from the Pi gpio pins.

Also, you might get more replies from the Hyperion forum

Thx, guys, I’ll do that today :slight_smile:

Could also be the case, but most of the time you get away with it :wink:

Btw, I’ve found those cheap Ebay mosfet level shifters to be pretty crappy.

I now use only 74hct series chips as level shifters.
74hct125 is ideal, but nearly many 74hct chips will do if you’re creative.


Turns out that it was ground issue. When I connected led ground to gpio everything worked like a charm.
For now ( 5 minutes usage) seems like 5v 2a is pretty enough and no shifter is needed.
Thanks you all, guys!

You should still consider a higher powered psu. There may be some white scenes and your 2a psu might get pretty warm or cut out.

Probably a good idea to stresstest it by selecting full white on the remote and then see if the psu fails or bursts into flames.

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Just ordered 5v 6a 30w :slight_smile: