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How many LED's can the Arduino PRO mini run? Answered

I need to design a programmable flashing light source for small models. The Arduino PRO mini looks perfect, but how many white LED's can I run on an Arduino PRO mini 5v? Am I right in thinking that a 3.3v mini will not power them? I would like to use at least 3 LED's but 6 would be great.

It will be powered by either a 9v, or coin cell battery if I can use the 3.3v version. I assume I can only use the coin cell on the 3.3v version, but use a 9v battery for both versions as long as I connect to the RAW input is that right?



You still not specifying what LED's you want to use....
How to wire LED's is explained in detail in many examples from the Ardione code libraries, if in doubt ask my friend Google.
For the basics:
A standard LED uses around 20mA.
So you can run for a while on a coin cell, many for minutes or just seconds.
A bit better for a 9V battery, but do the math yourself...

I should also mention that I will want to connect the LED's (via wires) to the mini, no space for a breadboard. How would I coonect the grounds?