I just got a big dome button from sparkfun: https://www.sparkfun.com/products/11275
I'm a bit confused about how to hook this LED up to my arduino without frying it. I have a PN2222A transistor. I'm just not sure how to put it together. This is my first time working with this kind of switch.
So: I connect the 12v battery + end, to the positive terminal for the LED, then I connect one leg of the 2222A transistor to the ground terminal of the LED, one to the ground of the battery, and one to the arduino?
I feel that's not right (but maybe it is)?
I came by this blog post, but am still scratching my head a bit: http://blog.cornbeast.com/2013/08/driving-a-12v-led-from-a-5v-arduino-pin/
PS: For some context, this is a photo booth button. So, I'd like to use the LED in the button as part of the countdown indicator. You hit the button, it pulses every second for 5 seconds, then goes back to solid green. I already have the button coded, I just need a nudge with the physical set up.