Christmas light controller

[queennikki1972]

I was thinking of using this to control multiple strands of lights to come on outside, but I wanted to ask if you think it can handle running for hours at time and would a relay need a heatsink?? Would the GENUINE Arduino UNO need a heat sink as well...? Or maybe need a larger Arduino Mega or something.

https://www.amazon.com/8-Channel-Shield-Module-Optocoupler-Arduino/dp/B01ARS8OVQ/ref=asc_df_B01ARS8OVQ/?tag=hyprod-20&linkCode=df0&hvadid=241973970700&hvpos=1o3&hvnetw=g&hvrand=15506157387150555720&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-395268347022&psc=1

[StillTrying]

https://www.amazon.com/8-Channel-Shield-Module-Optocoupler-Arduino/dp/B01ARS8OVQ/

I can't imagine the Arduino would overheat driving the optos, or the relays themselves overheating. I think a 5V supply is needed on the relay board to drive the relays, don't know the current needed when all are energized.

[ledtester]

You won't need a heatsink for either the relays or Arduino.

How often are you going to be switching the relays on and off? The contacts have a mechanical lifetime which is dependent on the amount of current they are passing.

http://zone.ni.com/reference/en-XX/help/375472H-01/switchhealthcenter/relay_lifetime/

[queennikki1972]

I plan on connecting 8 separate ac outlets (1 to each relay) then one string maybe two strings of lights to each outlet. short runs of lights about 10-20ft long. The on and off sequence may vary from every 500ms to 1500ms at a time. I may later connect it to music.

[queennikki1972]

I will only use this in the evening time for about 2 weeks a year at 4 hours at a time.

[queennikki1972]

If the relay clicked every 1000ms aka every 1 second for 4 hours for 14 days that's 201,600 clicks, right?

[queennikki1972]

Says the lifetime of the mechanical and electrical switch is 1 x 10 7 OPS. I'm not very good at scientific quotation, can someone interpret.?

[james_s]

Triacs are much better than mechanical relays for controlling line voltage lights. You can even do dimming in software if you include a way for the microcontroller to detect the zero crossing of the AC waveform.

1 * 10^7 is just a 1 with 7 zeroes, so 10,000,000 operations.

[ledtester]

The mechanical relays will work for at least one season, but I'd go with a solid-state relay module like this:

https://www.amazon.com/SainSmart-Channel-Duemilanove-MEGA2560-MEGA1280/dp/B00ZZVQR5Q