With Instructables you can share what you make with the world, and tap into an ever-growing community of creative experts.
Tell us about yourself!
LED nightlight that turns on in the dark
Should be 12 VDC.
Hello, im using a home made arduino to power an led matrix of about 120 leds. Anyways i would like to have the arduino shut off in light, on in night. I would like to set this up inbetween the 5 volt regulator and the atmega chip. Any idea what reaistance i should use so my atmega still works fine at night? ( its a 24x6 matrix for my 5 year old ). Thanks!
Brightresistance(10lux)(k):30-90Dark resistance(m):5GL5516 LDR
2N3904 TO-92 NPN General Purpose Transistor
I made this for my 6v 500ma solar panel. It charges a small battery(4.2v about 1ah, so small) and I connected the circuit to my battery, but the led was not powerful enough. and the power draw when the light is in off state is too high. my battery didnt charge like it was used to without the circuit.
The circuit remains on even if it is emitting no light. Consider using a 5v arduino power source. - AndrewB254
Only reason I replied is because I stumbled across this tutorial while searching for a nightlight tutorial for a friend. Cheers. - AndrewB254
This is a DC circuit and relies upon Direct Current. Ac current flows in the form of a sine wave and as such would not work using this particular design. Also, the resistors are all 1/4 watt, you would need much larger watt resistors to power an ac bulb, and a much higher current photo resistor. - AndrewB254
Play around with the resistors. You can probably replace the 1k with a 500ohm. Don't know for sure though - AndrewB254
Join 2 million + to receive instant DIY inspiration in your inbox.
Download our apps!
© 2016 Autodesk, Inc.