Hi spark community,
I just recently purchased a set of Lumini-rings from Sparkfun and have set to work playing with them, but I have questions now that the Hook-up guide and schematics cant answer
- Do lumini rings need resistors on the 5v, Data, or clock lines?
So far I haven’t seen anyone using resistors on this product, so is it built into the board?
- Can a typical Arduino handle a 2-3" lumini ring fully illuminated at safe levels?
It seems the current draw from even a 2" lumini is too much for an MC
Bardic College:
Do lumini rings need resistors on the 5v, Data, or clock lines?.. is it built into the board?
No there aren’t resistors built into the board but the 5V line from the Arduino/RedBoard should be very steady and can be used with out them for operation. It is suggested that if you daisy-chain several together then you can add a decoupling capacitor to help smooth out any voltage bumps. You can find that in our [Hookup Guide.
Bardic College:
Can a typical Arduino handle a 2-3" lumini ring fully illuminated at safe levels? It seems the current draw from even a 2" lumini is too much for an MC
Each LED is rated to pull a max 18 mA, so on the 2" ring, you can expect a pull around 720 mA. That is a lot of power to expect from our microcontroller boards. In the hookup guide, it does suggest several options for power supplies to help keep your microcontroller safe from having to solely power the LEDs. You can find that list [here](https://www.sparkfun.com/categories/307?_ga=2.231423448.673980155.1581351790-2114068872.1578439588)](https://learn.sparkfun.com/tutorials/lumini-ring-hookup-guide?_ga=2.209379157.673980155.1581351790-2114068872.1578439588#hardware-overview)
The last example I played with was “DemoReel100” from the FastLED library. I’m sure the lumini-ring didn’t like it.
I am driving a 2" lumini with an Arduino Uno: 5v pin, data & clock are pins 11 &13
The Sketch runs a few seconds then the ring begins flashing bright white, some LEDs stay on full white and are out of sync with the rest, some LEDs strobe.
It has done this twice now; thankfully it doesn’t seem to have permanently harmed the ring, and I don’t run the program anymore. I can run Fire 2012 with no problem.
My next step is to add a capacitor to the ring, either on the pads or in line, I’m thinking it might