Introduction: 230V AC PWM Dimmer Controlled by Arduino, Raspberry Pi

Picture of 230V AC PWM Dimmer Controlled by Arduino, Raspberry Pi

Cheap, easy, galvanic isolated and powerful 230VAC dimmer controlled by PWM output from Arduino, Raspberry Pi etc.

Step 1: How Does It Work

Buy cheap AC dimmer on eBay, which is controllable by manual adjustable resistor. http://www.ebay.com/itm/4000W-AC-220V-SCR-Voltage-...

Connect parallel to manual adjustable resistor photoresistor, place photoresistor to dark box together with LED.

Control LED light by PWM output.

Step 2: What Do You Need

Picture of What Do You Need

Step 3: Schema

Picture of Schema

Comments

VincentT57 (author)2017-06-13

I received same dimmer, but it doesn't work. Above rotating potentiometer, it has one more variable resistor (blue box). I just guess it have to be adjusted to some Ohms, I tried all, but dimmer still produce full voltage. Guys, can you help please, what to do with it?

bcsedlon (author)VincentT572017-06-14

How did you test it? Best way is use old style bulb with fiber.

Orngrimm (author)2016-07-14

safety is always good. thanks for posting the 'ible.

I really would suggest to remove the adjustable resistor and have only the LDR there. Be sure your LDR and the removed adjustable resistor have the same value-range to be able to use 0-100% PWM.

If you connect the LDR in parallel, you will NOT be able to use it 0-100% since you will create a parallel circuit...
you know the formula:
1/Rtot=(1/Rldr)+(1/Radjust)
so the worst thing: if you have the adjustable resistor on 0ohm, would will always have 0 ohm across all. with changing the adjustable resistor, you change the complete range of possible PWM...

just save the hassle and replace it with the LDR... don't go parallel... ;)

bcsedlon (author)Orngrimm2016-07-14

You are right. During my test adjustable resistor was so high that I was able control full range in parallel connection. This gives a possibility to control manually or by PWM. For sure adjustable resistor has to be set maximal resistance position to control only by PWM.