How many Plasma lights can the Picade X HAT drive?

Picade
1

I’m considering a build that could potentially use more than 10 buttons, and the Plasma buttons are definitely pretty! Can the Picade X HAT drive more than 10 Plasma buttons, or is 10 it’s limit?

Thanks!

2

They are chainable and you can alter the number of ‘pixels’ in code. The limiting factor would be current, I’m not certain how many would be supported before brownout.

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3

Yeah it would be 3A minus what the Pi and picade use. Maybe 1A to play with? Probably slightly less than that. My best guess anyway.

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4

I’ve run 16 in series, but no more than that yet. You can mitigate the power problems you might get from trying to run more by just running them at a lower brightness.

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5

Thanks gadgetoid! I’ll keep that in mind for my build.

6

Any tips on adjusting the brightness of the plasma LEDS ?’

plasmactl does not seem to support setting the brightness, and hacking the code manually exceeds my python skills ;(

Has anyone managed to set the plasma brightness ?

7

Maybe look in /etc/systemd/system/plasma.service or /usr/bin/plasma

8

setting colours to somthing other than 255 reduces the brightness

eg

plasmactl --colour 0 0 1

Sets all led to blue with minimum brightness.

9

I’m working on adding brightness control to Plasma/PlasmaCTL but it’ll require a fix to the library too. If you can figure out how to get stuff installed from the repo, the work-in-progress is here: Add brightness control for forum post 10985 by Gadgetoid · Pull Request #11 · pimoroni/plasma · GitHub