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Topic: powering an everyday light bulb connected to an arduino board (Read 1 time) previous topic - next topic


Hello everyone,

I am trying to sync a candle flame and light bulb so that they flicker together, but i would like to use a household light bulb, i am very new to electronics and to the arduino board, how is it possible to get enough power to light the bulb, the syncing of the flicker of the candle flame and light bulb is very important is connecting to the mains an option? i have been looking into online and i have seen a use of a relay but still am unsure how to go about it...




amazon has a few cheap relay types my favorite is http://www.amazon.com/SainSmart-4-Channel-Relay-Module-Arduino/dp/B0057OC5O8/ref=sr_1_16?ie=UTF8&qid=1332943785&sr=8-16 5v power relay, with 4 inputs. The are reverse logic I beleive, So low is On and High is Off little red light will show so.


A relay will only control the light at a level of on or off.  It will be easy to mimic the flicker/waning of a candle with an LED as you have greater control on it's brightness.
Reading a candle should be easy as there are a few kinds of light sensors.


Controlling a light bulb connected to the mains requires a SSR, Solid State Relay. There are several kinds, the type you want is known as a phase angle dimmer, or proportional dimmer. You feed the input with signals from the PWM output to change the brightness in response to the changing brightness of your flame.

However the fact that you are asking the question, and the manor you asked it, would change my advice to please ask some one who knows about electricity to wire this up for you. Mains can and does kill and I would hate for you to be eligible for a Darwin Award.


You might want to try a 12 Volt DC bulb for a car turn signal. That gives off a lot more light than a candle.

You can use a simple logic-level transistor (like a TIP120) to vary the bulb's brightness. Just hook the base of the transistor up to a PWM output pin of the Arduino and use an analogWrite command to set the brightness of the bulb.

You will probably want a 12 Volt DC power supply (although even 5 Volts gives reasonable brightness), but it's pretty easy to find 12 Volt wall warts.

Using a bulb like that will probably be safer and easier than using a bulb designed for mains power. As has been pointed out, that's not something you want to fool with when you are first starting out.


yes it might be better for now to use a 12v light bulb, thanks for all your help, much appreciated :)


Since you are new to electronics, you may want to follow this tutorial: itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads It tells how to vary the brightness of a light bulb using a transistor. For your candle project, just use a light sensor (as recommended by hellonearthis) instead of the potentiometer in the tutorial circuit.

I just bought a 12 Volt DC bulb from a local auto parts store and soldered a couple of wires on the base. You could also buy a socket.

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