Hey guys, I plan on fabricating my own chandelier lift in my attic using a hoist from Harbor Freight. I plan on having 2 limits on the cable which will automatically shut off the lift when it reaches the correct heights (all the way up and down), similarly to how all hoists have a limit switch when they are retracted all the way.
One slight problem is that I dont want to climb into the attic each time and also dont want to run 4 wires through 2 floors into the basement then back up to where the chandelier switch is to control it there. So I was thinking on having Smartthings control 2 relays (one for up and one for down) for around a minute (the relays will run for a minute but the hoist will automatically stop when it reaches the limit height).
I came here looking for any suggestions and the best relay(s) to use. I was also thinking about using an alternating relay (one for up and one for down) and having only one z-wave relay that triggers it to keep cost down.
You can use a MIMOlite for this. It has one normally-open contact and one normally closed contact. When the relay is “ON” you’ll get “down”, and when it is “OFF” you’ll get “up”. You don’t want to use a dual relay because you can’t garuntee that ST will always turn off one relay before starting the second one.
You have to be careful with this sort of winch product. The winch is definitely not rated for unattended use (which can occur when connected to Smartthings).
Furthermore, I don’t believe HF makes a winch with a grooved drum. This means that the limit switches (especially at the upper limit) will be inaccurate. The cable will stop at different heights depending on how it overlaps itself as it spools on the drum. Each revolution won’t necessarily give you a consistent height change of your chandelier. You might end up driving your chandelier through your ceiling one day. Winches that are designed for accurate positioning like this always use a grooved drum
I just started digging into this, and what we have is a lift purposefully designed for this by Aladdin Light Lifts. I’m not sure about getting by with just one Mimolite just yet, but I think you’re right. For our lift, turning right is on and it goes down, and stops when ever the key is back in the center position (off). Turning left is obviously up and on. Like I said, I’m just now contemplating this and I’m hoping to find the installation manual that came with our lift.
Notice how the black rubber washer will hit the upper limit switch and prevent the user from raising it any higher. I plan on using this for the top limit and creating another one for the bottom limit.
Are you saying that the winch will continue for a small distance after the switch is engaged?
Wow, holy cow now that’s a winch for one heck of a chandelier. Serious, look for a lift system designed for lights. When it comes time to sell your home and pass inspections, you don’t want to have to undo something like that.
Wouldn’t this mean one of the two modes will always be active? How about something like this:
Not sure how the lift works, if it has two motors or it has a single reversible motor, or two power inputs, etc. but the schematic above ensures only one input is on at any time.
If you need dry relays to simulate the buttons, add two dumb relays after that:
RY1 and RY2 are mimolites, so their power is AC, RY3 and RY4 are dumb SPST relays and their power is DC, BT1 needs to match their nominal voltage. Then the dry contacts of RY3 and RY4 overlap the key pins for up and down. Only one can be on at any given time, thus mechanically ensuring you’re not going to ask the chandelier to go both ways at the same time. Even ST can’t mess that up anymore
That will certainly work better than a winch that counts revolutions for its limits… but I don’t see how you’ll make a low limit with that system.
Simple, have a washer like the rubber one I showed in the attic and have two stoppers on the steel cable at the right heights. When the lower limit is reached the stopper will force the washer down with force enough to trigger a spring loaded switch that then breaks the connection to the lowering button. When the winch is raised the other stopper will pick up the washer and have it hit the upper limit.
