It's not for dimming as it is a constant color.
I Was googling trying to find a low voltage sensor, basically something with an independent power source to illuminate at a programmed low voltage. Anyways ended up buying a cheap $7 tiny volt meter with an independent power source to wire to my secondary o2 sensor readings. It's small enough to hide in plain sight.
I lack the engineering skills to create a sensor to illuminate at less than .9 volts
http://www.amazon.com/dp/B00C58JGE6/...Mini+voltmeter