PWM many 12V/100mA LEDs

[espruino-discuss3]

Posted at 2022-03-23 by Owen

Hello,
Sorry this isn't strictly Espruino related but wondering if someone could point me in the right direction.

I'm looking at getting 50 of these 1W fibre optic light sources for an art project. https://www.adafruit.com/product/4168
They are simply LEDs that require 12V and 100mA.
My question is what do I need to be able to dim each one individually?
I found this nice PWM LED driver board but each output can only handle 30mA https://www.adafruit.com/product/1429
Do you know of any driver or other idea that could allow me to accomplish this?

[gfwilliams]

Posted at 2022-03-30 by @gfwilliams

I'm not sure of anything all-in-one, but you could use that PWM LED driver (or any other PWM driver chip) and could then add something like a ULN2003. They're cheap and you get 7x 500mA outputs per ULN2003 and you basically just wire straight through.

[espruino-discuss3]

Posted at 2022-03-30 by Owen

I don't think my eletricronic knowledge isn't good enough to create custom pbc using chips like that. But it's a good option.
For now I found these DMX decoder boards that can supply 9-24V@4A per output which is more than enough.
https://www.aliexpress.com/item/1005003306910345.html

[gfwilliams]

Posted at 2022-03-30 by @gfwilliams

Those DMX decoders look great - definitely a nice easy option especially as they seem to do PWM too.

I wouldn't let the fact the ULN2003 is a chip put you off if you need something similar in future though. You just wire up ground, then 7 signal wires in, and 7 signal wires out right opposite - you hardly even need a PCB (although there are some breakout boards available).

Attachments:

• uln2003.png