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can I use a digital dimmer on these Christmas lights?

Posted: Wed Nov 21, 2018 7:40 am
by lpdescamps
Hi, do you think I could use this digital dimmer to do a glow/fade effect on a 15m xmas led lights using a RPi Zero?
The lights are 220V/AC

Digital Dimmer: https://www.ebay.co.uk/itm/Digital-Dimm ... GgWX5R04gE

Xmas LED Lights: https://www.festive-lights.com/outdoor- ... s#217=1591

thanks

Re: Christmas

Posted: Wed Nov 21, 2018 8:51 am
by mattmiller
No

Those LED lights will powered from their own transformer and rectifier and will be incompatible with a mains dimmer (most Christmas lights are like this nowadays)

Re: Christmas

Posted: Wed Nov 21, 2018 6:08 pm
by lpdescamps
the lights are 220v ac without any transformer

Re: can I use a digital dimmer on these Christmas lights?

Posted: Wed Nov 21, 2018 7:03 pm
by Brandon92
I think you are forgetting a part with that Christmas light, you also need to by something like this to control that light string. And those "starter cable" will regulate the output to the leds. So, if you change the voltage at the input. The led dimmer controller will not response will to that.

Also, by the look of the dimmer that you have chosen. It look like it is NOT SAVE to use for you. Because the layout of that board is not good.
The clearance between the life side (high voltage part) and your Rpi connection is not at a save distance from each other.

edit
I don't know your knowledge about this topic. But a other possibility could be that you use a dimmer that can be used with you lights. (for example the link that I provided*). And modifide it, so that you can control it with your Rpi. For example a save way of doing this could be this: you buy something like this solenoid that would push the bottom of the controller. In this way you can dim the light in a save way. And you could mount as a bonus a ldr (or other light sensor) to one of the light in the Christmas light. Than you can check if is on or off.

*not 100% if it is the correct one for you

Re: can I use a digital dimmer on these Christmas lights?

Posted: Wed Nov 21, 2018 8:45 pm
by mattmiller
the lights are 220v ac without any transformer
Sorry - I didn't notice that bit!

It could be technically possible that they may respond OK to the dimming controller (but they may not)

Only trying them out would tell.

But I'd always warn someone that DIY mixing mains electricity and Pi is not recommended and potentially illegal depending where you live

Much safer to just buy some lights with an indoor transformer and controller :)

Re: can I use a digital dimmer on these Christmas lights?

Posted: Mon Dec 10, 2018 7:00 pm
by lpdescamps
thank you for your advice.
i decided to drop the idea this year (again) and go with 24v and a controller to slow glow the lights...
i would love to find a controller for Rpi and play a bit with it.
any idea?
thnaks

Re: can I use a digital dimmer on these Christmas lights?

Posted: Mon Dec 10, 2018 7:42 pm
by Andyroo
Never drop an idea with shopping days left (unless you know its going to be in the New Years sale) :lol:

Have a look here - its a bit old but should still be doable https://www.raspberrypi.org/blog/christ ... sequencer/

You could also go really over the top (of the roof) with https://www.youtube.com/playlist?list=P ... oXM_l-yb-8 or https://www.youtube.com/playlist?list=P ... 8q8TkA2B8m

For a more low level hack try https://youtu.be/NqFUeIY8CIM


Do not blame me for loss of sight (you may need sun glasses and/or ear plugs for some of these), damage to hearing or burning your house down :lol: