First, the question: what relays would be good to use as part of an arduino controlled Light Switch toggle.
I run a small motel in Northern Michigan. We currently have a few sets of outdoor lights that are operated from within the main office/lobby. The wall plates with a total of 9 switches across three 3-switch plates, however due to remodeling my the previous owners only about 6 or 7 are really used/working.
all are ON/OFF switches
Motel Sign (want to toggle via light sensor)
Vacancy Sign (doesn't really need to tun off unless motel is shut down)
'No' before Vacancy (currently not working, may be issue in sign, we're looking into it but its not part really of the scope of this topic)
Office Sign (possibly turned off during day)
Covered Drive Lights (light sensor)
Outdoor Ice Machine (could be toggled via temp sensor for automatically shutting down before it gets too cold for the machine to run)
Lobby Power Outlet toggle (may be replaced with always-on outlet, but not sure. currently used to turn off glass display case light when office is closed for the evening)
I currently have an Arduino Uno for development, but i could easily buy a mini or nano for the final version. I would like to replace the 3 Triple-Switch panels with a system that allows me to have most if not all of these connections turn on and off at different times. There would still need to be switches of some kind as overrides, and having smaller switches is always a plus.
I only really need to know what would be the best method and relays for this. I have seen reviews of relays that are wired into a 3-wire power cable, but will this also work with the power cables in the walls the same way?
I don't need any sort of dimming, just simple on/off.
A relay would fit your needs; it's essentially a physical switch that is actuated by an electromagnet. Here's an example to get your started; in this case you'd just feed the board 5V, GND, and digitalWrite a high 5V to the corresponding input pin of whichever relay you want to switch.
Each of the relays presents three screw terminals; when unenergized or at rest it has a circuit between NC (normally closed) and COM, and when the relay is energized it creates a circuit between NO (normally open) and COM. In your case you might want to feed the hot wire from the existing switch to COM and the wire to the light you're controlling to NC so that if your Arduino loses power you can still use the switch to operate the light.
fuse panel ----> switch ----> NC and COM -----> light
Pretty straightforward stuff but you should get an electrician involved to recommend the appropriate chassis and mounting for the relay panel. Things like this will likely make your building inspector antsy.
Chagrin:
A relay would fit your needs; it's essentially a physical switch that is actuated by an electromagnet. Here's an example to get your started; in this case you'd just feed the board 5V, GND, and digitalWrite a high 5V to the corresponding input pin of whichever relay you want to switch.
Each of the relays presents three screw terminals; when unenergized or at rest it has a circuit between NC (normally closed) and COM, and when the relay is energized it creates a circuit between NO (normally open) and COM. In your case you might want to feed the hot wire from the existing switch to COM and the wire to the light you're controlling to NC so that if your Arduino loses power you can still use the switch to operate the light.
fuse panel ----> switch ----> NC and COM -----> light
Pretty straightforward stuff but you should get an electrician involved to recommend the appropriate chassis and mounting for the relay panel. Things like this will likely make your building inspector antsy.
Thanks for the info. We know the local electrician, and the area for the relay panel is a nice large size (about 6.5"W x 14.5"H).
Would it be possible to use the relay board you linked (or any of the other relay boards with less relays, the 1-channel, 2-channel, etc) with a standard AC power cable as a test run?
macharborguy:
Would it be possible to use the relay board you linked (or any of the other relay boards with less relays, the 1-channel, 2-channel, etc) with a standard AC power cable as a test run?
If I were running tests I'd use less dangerous circuits -- like a LED or small DC motor or such -- but yes.
The screw terminals are just large enough to hold a 12ga solid wire, but again the relays are limited to 10A. I assume that an electrician would suggest you bump your breakers down to 10A as well in order to be kosher. You'll also want to grab a few standoffs so you can mount the board to something; there are bare pads sticking out underneath the board that cannot be allowed to touch anything.
macharborguy:
Would it be possible to use the relay board you linked (or any of the other relay boards with less relays, the 1-channel, 2-channel, etc) with a standard AC power cable as a test run?
If I were running tests I'd use less dangerous circuits -- like a LED or small DC motor or such -- but yes.
The screw terminals are just large enough to hold a 12ga solid wire, but again the relays are limited to 10A. I assume that an electrician would suggest you bump your breakers down to 10A as well in order to be kosher. You'll also want to grab a few standoffs so you can mount the board to something; there are bare pads sticking out underneath the board that cannot be allowed to touch anything.
very good advice. I am currently using some relays to do DC motors tests, using two relays to toggle between off, forward and reverse. I doubt these specific relays that i have currently are really meant for heavy electrical use like my sign project would consist of, but i can always get the proper ones once I get to that project in full. And yes, I would make sure that electronics are spaced well enough apart securely.