Hi, apologies if this has come up before, had a quick search and couldn’t find a similar post…
Simple question: I’ve a project where I’m wanting to drive a single LED at a constant frequency (set by software) in a portable device where the lifetime of the LED is critical. I’ve reservations that running the LED in series with a resistor directly off an Arduino output pin will reduce the lifetime of the LED. How stable is the 5V from these pins? I understand that small changes in the voltage can lead to significant changes of current through the LED, so I wanted to consider other options.
The only requirements I have is the circuit needs to be low power (as this is a portable device running off batteries), and the current through LED as constant as possible when it is on.
One option is using the LM334 as a constant current source where the voltage comes from the Arduino pin, switching 0-5V at the desired frequency (which will be in the kHz range).
Any other suggestions welcome… thanks in advance!