I'll also note the TeslaLED app as another good one - it requires camera permissions to control the LED, plus screen drawing and sleep control - I suspect around the minimum that would be needed for a flashlight app.
This is what I've always used. LampA doesn't work on my Galaxy Nexus. I was hoping it would start up quicker because my biggest peeve with Tesla is that it takes time not only to open the app but there is a hundreds of ms delay in turning on the LED. I assume the complexities causing this are also what prevent LampA from working.
https://play.google.com/store/apps/details?id=com.teslacoils...