I just finished making my canopy raise/lower electronically with a linear actuator, and wanted to share the full details of the build. I'm not the first person to use a linear actuators to raise/lower my canopy, nor am I the foremost expert on them, but I found in my research while there was a lot of good information in various build threads, I didn't see a single thread with a full example from start to finish. So hopefully I can fill that niche.
I also did it very inexpensively, the entire build was just over $100. A lot of this cost savings was buying a linear actuator from eBay instead of one of the name brand stores that charge a lot more. If you are the type of person who wants something with a good warranty and are willing to spend a little extra, there are a lot of high quality stores that specialize in linear actuators and accessories. There also are less expensive options on eBay and Amazon. I'm not endorsing either option.
Part List
Electronics
Linear Actuator (my cost: $46)
I purchased a 12V, 12" extension with 200 lb max lift and 12mm/sec speed on eBay. It also included mounting equipment. I'll break down all of those things.
12V
There are DC and AC linear actuators. The DC versions are cheaper, more common and I prefer working with 12V DC. For the rest of this guide it assumes you have a 12V DC version.
200 lb max lift
This is the maximum dynamic lift for this actuator, meaning how much weight it can actually push and pull. My canopy weights about 50 pounds so this will easily handle it. For any common linear actuator, the static lift (IE holding the weight in place when the actuator is off and not moving) will be much higher. If you buy a linear actuator from a name brand company they will probably have a spec sheet that lists both the dynamic lift and the static lift. Mine didn't since it was a cheap ebay one, but you can assume static lift will always be at least the dynamic lift, so in my case I'm covered.
12" extension
This is how far the actuator will move from one extreme to the other. For example the one I bought is 16.125" when fully retracted and 28.125" at maximum extension. IE 12" difference from one extreme to the other. One of the benefits of linear actuators is that they come in all different lengths, so you want to buy one for the amount of lifting you want to do. If you want to lift your canopy 8", get an 8" extension. If you want to lift it 12", get a 12". Now if you want to raise your canopy 8", you also *could* get a 12" extension. But most LAs have built in limit switches at both extremes that turn it off when fully retracted or extended. This is nice because you can flip the switch to raise your canopy and walk away, and once the LA reaches the fully retracted extreme, it shuts off automatically.
For my particular case I actually only need to raise and lower my canopy 6", but I already have a pulley system setup which makes it so 12" of pulling only raises the canopy 6" (this was so when I was manually pulling it I had some mechanical advantage). Since I didn't feel like changing the pulleys I went with a 12" extension.
12mm/sec speed
This is how fast the LA moves. So that means it takes about 25 seconds to extend/retract the full 12" (which raises/lowers my canopy 6"). For me this speed is fine, but there are faster ones out there.
Mounting equipment
I made sure to buy one that included 2 mounting brackets (though I only needed one). You need some way to mount the linear actuator to a fixed point somewhere. You can also get the mounting brackets separately just make sure they fit the linear actuator you get.
Power Supply (my cost: $16)
Again check the spec sheet, but I think the max draw of my particular LA is 3-4A, so I got a 12V 5A table top power supply. They are available from many places. If you happen to have a junk bin of old adapters, you can look in there and you might already have one from an old laptop.
I bought this one, which at $16 was a good deal from a reputable manufacturer.
A good default choice for power supplies is Mean Well, and here is their standard 12V/5A table top power supply for $21.
Both of these links are from Jameco which is an eletronics store that happens to be near where I live. There are many like it, just search for "Mean Well 12V 5A" and you'll have many options.
You can buy cheaper ones on eBay too, but I'd make sure whatever you get is UL approved. You don't want some cheap power supply catching fire.
Toggle Switch (my cost: $4):
You are going to want a switch for your LA that can change it between forward-off-reverse.
I went with this stylish toggle switch that also was from Jameco.
The name brand companies will also have a variety of switches at slightly higher price points. And in fact they'll also have remote control systems that incorporate both the power supply with a remote control that will do it all for you. Those are a bit more expensive and less DIY, but probably good options for many people.
Some place to mount the toggle switch (my cost: $7)
I mounted my toggle switch in a utility box I picked up at HD. You really can mount it anywhere you can put a 1/2" hole.
Misc
You'll also need some way to connect all the wires. I used electrical tape, wire caps and some spare wire I had lying around. Use whatever method you like.
Mechanical
Now the rest of the stuff is very specific to your individual needs. Basically you need to rig your lights via pulleys so there is one cord where if you pull it X", it raises your lights Y", where X is the extension length of your linear actuator and Y is your desired height.
In my particular case, I pull the cord 12" and my lights are raised 6".
There are all sorts of clever ways people have done this to hide the linear actuator and make the whole setup look really cool. Mine is rather janky and I recommend you do better than I do, But the linear actuator's brute force power makes up for my shortcomings.
Pulleys (my cost: $24):
My Hamilton Cebu fixture has 4 lift points, so I used 4 1" fixed pulleys and 2 1.5" wall/ceiling mount.
Only the wall/ceiling mount pulleys were truly necessary in my case, but as I said above I already had the other pulleys on there already for when I lifted it by hand.
Rope (my cost $5):
I used 1/8" paracord with 160 lb working load limit. I don't recommend this. Use wire rope, which looks better, is stronger and doesn't stretch. It will cost you a little more but is much more suitable for this application. However for my particular usage the paracord is working fine and cheap (and cheap looking!).
Wiring It Up
The whole setup is quite simple to wire up.
The linear actuator will have 2 wires coming out of it.
Depend on what type of power supply you got, it will either have 2 wires coming out of it or a little connector like this:
If it has a connector, cut it off and then peel away the cord so you have 2 wires.
So now you have 4 wires and a toggle switch with 6 spots. We'll label the wires coming out of the linear actuator as 1 & 2, and the wires coming out of the power supply as 3 & 4. You wire the toggle switch as follows:
So basically you put the power supply in the middle, and on each side you connect the linear actuator wires one way, and then the other way. So as you flip the toggle back and forth you are just switching the polarity making the motor run one way, and then the other.
That was easy. If the switch is "backwards" and you want to flip the directions, just flip the 3 & 4 wires on the toggle switch.
Now just mount your toggle switch however you want. Here is my toggle switch in the utility box:
Mounting
This is going to depend on whatever type of mounting method you chose.
For my method I took the mounting bracket that was included and attached it to the ceiling. The screw that has the arrow pointed at it supports the weight for everything (canopy + linear actuator + rigging), so you must screw it into a stud/joist/something anchored. I'd recommend using a properly sized lag screw. I would have used a lag screw if I had the proper size lying around, but I didn't and in my case a 2.5" wood screw is working fine.
The linear actuator mounts to the mounting bracket with a steel pin, and it is designed so the linear actuator can pivot around this pin. For my installation I don't want the linear actuator to pivot so I used a zip tie to keep the front of the linear actuator level. This of course isn't load bearing, and when the linear actuator is under tension it will be held level anyways.
And then the final step is to connect the rod to the rope that needs to be pulled. I used a trusty bowline knot, but this will vary for whatever particular mounting method you chose.
Many ways people using linear actuators take advantage of the pivoting and extremely high torque to put the linear actuator in a cool places. Use your creativity, my approach is very prosaic.
We're done!
Here is a video of my canopy going up and down at 5x speed.
In my case when the canopy is in the "down" position, it is held by some metal rigging and not by the linear actuator. In theory the linear actuator is more than strong enough to hold the canopy in the down position, but personally I'm not going to depend on that. I'd recommend to make sure if you linear actuator breaks, the canopy doesn't fall into the aquarium.
However, if you decide to use your system to acclimate corals by moving the canopy up and down, you shouldn't have any issue with having the linear actuator supporting the weight of your canopy, even for long term usage.
I also did it very inexpensively, the entire build was just over $100. A lot of this cost savings was buying a linear actuator from eBay instead of one of the name brand stores that charge a lot more. If you are the type of person who wants something with a good warranty and are willing to spend a little extra, there are a lot of high quality stores that specialize in linear actuators and accessories. There also are less expensive options on eBay and Amazon. I'm not endorsing either option.
Part List
Electronics
Linear Actuator (my cost: $46)
I purchased a 12V, 12" extension with 200 lb max lift and 12mm/sec speed on eBay. It also included mounting equipment. I'll break down all of those things.
12V
There are DC and AC linear actuators. The DC versions are cheaper, more common and I prefer working with 12V DC. For the rest of this guide it assumes you have a 12V DC version.
200 lb max lift
This is the maximum dynamic lift for this actuator, meaning how much weight it can actually push and pull. My canopy weights about 50 pounds so this will easily handle it. For any common linear actuator, the static lift (IE holding the weight in place when the actuator is off and not moving) will be much higher. If you buy a linear actuator from a name brand company they will probably have a spec sheet that lists both the dynamic lift and the static lift. Mine didn't since it was a cheap ebay one, but you can assume static lift will always be at least the dynamic lift, so in my case I'm covered.
12" extension
This is how far the actuator will move from one extreme to the other. For example the one I bought is 16.125" when fully retracted and 28.125" at maximum extension. IE 12" difference from one extreme to the other. One of the benefits of linear actuators is that they come in all different lengths, so you want to buy one for the amount of lifting you want to do. If you want to lift your canopy 8", get an 8" extension. If you want to lift it 12", get a 12". Now if you want to raise your canopy 8", you also *could* get a 12" extension. But most LAs have built in limit switches at both extremes that turn it off when fully retracted or extended. This is nice because you can flip the switch to raise your canopy and walk away, and once the LA reaches the fully retracted extreme, it shuts off automatically.
For my particular case I actually only need to raise and lower my canopy 6", but I already have a pulley system setup which makes it so 12" of pulling only raises the canopy 6" (this was so when I was manually pulling it I had some mechanical advantage). Since I didn't feel like changing the pulleys I went with a 12" extension.
12mm/sec speed
This is how fast the LA moves. So that means it takes about 25 seconds to extend/retract the full 12" (which raises/lowers my canopy 6"). For me this speed is fine, but there are faster ones out there.
Mounting equipment
I made sure to buy one that included 2 mounting brackets (though I only needed one). You need some way to mount the linear actuator to a fixed point somewhere. You can also get the mounting brackets separately just make sure they fit the linear actuator you get.
Power Supply (my cost: $16)
Again check the spec sheet, but I think the max draw of my particular LA is 3-4A, so I got a 12V 5A table top power supply. They are available from many places. If you happen to have a junk bin of old adapters, you can look in there and you might already have one from an old laptop.
I bought this one, which at $16 was a good deal from a reputable manufacturer.
A good default choice for power supplies is Mean Well, and here is their standard 12V/5A table top power supply for $21.
Both of these links are from Jameco which is an eletronics store that happens to be near where I live. There are many like it, just search for "Mean Well 12V 5A" and you'll have many options.
You can buy cheaper ones on eBay too, but I'd make sure whatever you get is UL approved. You don't want some cheap power supply catching fire.
Toggle Switch (my cost: $4):
You are going to want a switch for your LA that can change it between forward-off-reverse.
I went with this stylish toggle switch that also was from Jameco.
The name brand companies will also have a variety of switches at slightly higher price points. And in fact they'll also have remote control systems that incorporate both the power supply with a remote control that will do it all for you. Those are a bit more expensive and less DIY, but probably good options for many people.
Some place to mount the toggle switch (my cost: $7)
I mounted my toggle switch in a utility box I picked up at HD. You really can mount it anywhere you can put a 1/2" hole.
Misc
You'll also need some way to connect all the wires. I used electrical tape, wire caps and some spare wire I had lying around. Use whatever method you like.
Mechanical
Now the rest of the stuff is very specific to your individual needs. Basically you need to rig your lights via pulleys so there is one cord where if you pull it X", it raises your lights Y", where X is the extension length of your linear actuator and Y is your desired height.
In my particular case, I pull the cord 12" and my lights are raised 6".
There are all sorts of clever ways people have done this to hide the linear actuator and make the whole setup look really cool. Mine is rather janky and I recommend you do better than I do, But the linear actuator's brute force power makes up for my shortcomings.
Pulleys (my cost: $24):
My Hamilton Cebu fixture has 4 lift points, so I used 4 1" fixed pulleys and 2 1.5" wall/ceiling mount.
Only the wall/ceiling mount pulleys were truly necessary in my case, but as I said above I already had the other pulleys on there already for when I lifted it by hand.
Rope (my cost $5):
I used 1/8" paracord with 160 lb working load limit. I don't recommend this. Use wire rope, which looks better, is stronger and doesn't stretch. It will cost you a little more but is much more suitable for this application. However for my particular usage the paracord is working fine and cheap (and cheap looking!).
Wiring It Up
The whole setup is quite simple to wire up.
The linear actuator will have 2 wires coming out of it.
Depend on what type of power supply you got, it will either have 2 wires coming out of it or a little connector like this:
If it has a connector, cut it off and then peel away the cord so you have 2 wires.
So now you have 4 wires and a toggle switch with 6 spots. We'll label the wires coming out of the linear actuator as 1 & 2, and the wires coming out of the power supply as 3 & 4. You wire the toggle switch as follows:
So basically you put the power supply in the middle, and on each side you connect the linear actuator wires one way, and then the other way. So as you flip the toggle back and forth you are just switching the polarity making the motor run one way, and then the other.
That was easy. If the switch is "backwards" and you want to flip the directions, just flip the 3 & 4 wires on the toggle switch.
Now just mount your toggle switch however you want. Here is my toggle switch in the utility box:
Mounting
This is going to depend on whatever type of mounting method you chose.
For my method I took the mounting bracket that was included and attached it to the ceiling. The screw that has the arrow pointed at it supports the weight for everything (canopy + linear actuator + rigging), so you must screw it into a stud/joist/something anchored. I'd recommend using a properly sized lag screw. I would have used a lag screw if I had the proper size lying around, but I didn't and in my case a 2.5" wood screw is working fine.
The linear actuator mounts to the mounting bracket with a steel pin, and it is designed so the linear actuator can pivot around this pin. For my installation I don't want the linear actuator to pivot so I used a zip tie to keep the front of the linear actuator level. This of course isn't load bearing, and when the linear actuator is under tension it will be held level anyways.
And then the final step is to connect the rod to the rope that needs to be pulled. I used a trusty bowline knot, but this will vary for whatever particular mounting method you chose.
Many ways people using linear actuators take advantage of the pivoting and extremely high torque to put the linear actuator in a cool places. Use your creativity, my approach is very prosaic.
We're done!
Here is a video of my canopy going up and down at 5x speed.
In my case when the canopy is in the "down" position, it is held by some metal rigging and not by the linear actuator. In theory the linear actuator is more than strong enough to hold the canopy in the down position, but personally I'm not going to depend on that. I'd recommend to make sure if you linear actuator breaks, the canopy doesn't fall into the aquarium.
However, if you decide to use your system to acclimate corals by moving the canopy up and down, you shouldn't have any issue with having the linear actuator supporting the weight of your canopy, even for long term usage.
