Intro: Motorized Flip Down TV Lift
I’ve always thought that flip down TV mounts were cool, and have long looked for an opportunity (or excuse) to build one. A couple of years ago, we built a boathouse with a large covered area that is perfect for relaxing while staring out over the water. We wanted to add a TV to the covered section, but not block the view of the water when not watching it. Since the roof has a shallow angle that would not permit a slide-down type of mount, it was perfect for a flip down mount.
After pricing commercial units (thousands of $$), I decided to build my own. It took a while to puzzle out some of the details, but we’re happy with the result. You should be able to follow these steps to build one that fits your specific installation situation.
What you’ll need
3 / 4” Plywood
1 x 4 Pine or Poplar
2 Pillow Bearings - https://amzn.to/2t4TuO0
¾” steel rod - https://amzn.to/2Mz4qvr
Limit Switches - https://amzn.to/2yhJ02C
12VDC Linear Actuator - https://amzn.to/2JWRT2U
12 VDC Relays - https://amzn.to/2LZy8Zq
Power strip - https://amzn.to/2MA0L0k
TV mount - https://amzn.to/2tjp2yK
Directional switch - https://amzn.to/2t4v2MK
12 VDC 5 A Power Supply - https://amzn.to/2yiX7F6
Magnetic reed switch - https://amzn.to/2LZuSNu
Hookup wire - https://amzn.to/2M0Q5Xi
Terminal strip - https://amzn.to/2JWhklf
Cable grommet - https://amzn.to/2ymRmpD
Step 1: Step 1 – the Mechanism
This was the part that gave me fits. After lots of sketching and head scratching, I finally settled on a design that mounts the arms of the TV mount at a 45-degree angle to the rod of the linear actuator. A quick experiment with wood scrap and PVC pipe showed that this would work well.
I started with a 36” length of 3/4“ steel rod. I cut a piece of 1.5” steel tube about 12” long, then drilled a hole for the rod. After centering it on the rod, I held it at 45 degree angle and welded it in place.
Next, I welded up a frame for the TV mount out of 1” steel tube. Rather than trying to weld the flat tube to the round rod, I notched out a section for the tube to sit in, then added a similar, smaller section to the top, sandwiching the tube between them. Some grinding of my lousy welds and a coat of black paint and it was ready to go.
For the pivot, I went totally overkill and used pillow block bearings. Since the rod only rotates a quarter turn, I probably could have gotten away with bronze bushing and a bit of grease. Oh, well – next time.
After testing the mounting location of the actuator, I cut about four inches off the top of the pivot arm and installed the mounting bracket.
The finished mounting frame and bearings were then bolted into the wooden case with ¼” hex bolts and flange nuts.
Step 2: Step 2 – the Cabinet
This was meant for casual viewing, so we didn’t need a large TV. I picked a 32” set that would give us a nice viewing size and not be too expensive – since it’s installed in an unconditioned boathouse, humidity will eventually be a problem. That said, we’ve had a similar set in a cabinet on a screened porch for years without any issues.
I started with a simple box made from 3 / 4” cabinet-grade plywood that measures approx.. 36” wide x 36” deep x 9” high. Some experimentation with the size of the mechanism showed that I would need a bit more depth, but a taller box meant that it would hit the slope of the roof rafters. My compromise was to build a small “bump-out” on top of and behind the box that would enclose the pivot arm and slide in between the rafters.
After installing and testing the mechanism (Step 1), I didn’t like the way the case bowed when the lift was retracted. I added a piece of angle iron, bolted to the front and back, to make it more rigid.
Step 3: Step 3 – Details
Next, I added ¾” pine strips to the “bottom” (the part that faces down) to add strength and create a frame for the panel that would cover the TV. The panel was made by gluing up 1x4 pine and adding breadboard ends to keep it stable. After mounting the panel to the metal frame, it took quite a bit of fiddling to get the size & position just right – it needed about 1/8 “ of clearance at the front & sides, but about an inch at the back to give it room to clear the back of the case. I added ¾ strips around the inside to help seal the panel when it is closed. I didn't take any good pics of this, but you can see the panel and trim in the "finished" photo.
Once the panel was fitting well, I removed it and gave the inside of the case a coat of flat black paint. The outside was primed and got a coat of exterior latex (in a very unobtrusive brown).
Step 4: Step 4 – Electrical
Here’s the fun part.
The mechanism is operated by a 12”, 12 VDC linear actuator. I chose a model that’s a bit pokey – it takes almost 60 seconds to extend or retract – so that I could make my mistakes slowly. Power comes from a 12 VDC, 5 amp power supply. Direction is controlled by a spring loaded DPDT switch (only using half of the switch) that is mounted several feet away and connected via 4 conductor cable. The directional switch controls one of 2 relays, which are both wired to the motor. Since the directional switch is spring-loaded, there is no chance that both relays could be operated at the same time. Two SPDT microswitches are installed to stop the movement of the lid at the top and bottom limits.
Did you notice the two wingnuts that stick out of one side? These are wired directly to the motor. I was worried that the power supply would fail and leave me without a way to flip down the TV. If that happens, I can connect a 12 VDC battery to these terminals to operate the motor directly, open the case, and replace the power supply.
I decided to hardwire the directional switch – a remote would just be one more thing to lose (or replace the batteries in). It’s mounted on a post a few feet from the TV. Since this is a vacation home, there is a chance that someone could be on the dock while we’re not there. To prevent someone from operating the mechanism, I added a magnetic reed switch to the directional switch, located so that it is just below the top of the junction box. I 3D printed a holder for a small bar magnet and frame to hold it in place. Once the magnetic “key” is in place, the switch operates normally. Remove it, and nothing happens! The STL files for the key & frame are included.
The width of the case gave me room to mount a power strip and the directional relays on one side. A terminal block helps keep the wiring tidy and safe. Wiring for power, directional operation, and Ethernet (for a Roku) exits through a cable grommet on the side that faces away from the seating area. I didn't have an appropriate size grommet available, so I 3d printed one - the STL file is included.
Step 5: Step 5 – Mounting & Wrap Up
The TV is mounted above the framing of the boathouse. I attached a 10’ 2x4 to each side, then lifted it (with help!) so that the supports rest on the framing. We slide it into position, adjusting it so that the “bumps” for the pivot mechanism slip in between the rafters. I’ll trim the ends of the 2x4 supports once we’re sure of the final position.
I added a swingarm mount so the TV could be swung & pivoted to face other parts of the dock. The pictures show it with a temporary 24” TV and soundbar that we used for testing. We have a hardwired ethernet connection on the dock, but not cable, so the feed comes from a Roku and various sources (Netflix, DirecTV Now, Pandora, etc.)
I added some rubber weather stripping to help seal out moisture. I’m hoping it will also reduce the number of spiders that decided to make it their home, but I’m not optimistic – they get into everything! Not complaining too much, though – they are eating the bugs that would otherwise bother us on the dock.
A few things are still left - touch up painting and a better solution for mounting the soundbar.
Step 6: Step 6 – What I Would Change
I think of this as both a proof of concept and a finished product. If I build another one, I’d do a few things differently:
· I’d position the linear actuator and pivot arm to one side. Positioning it in the middle meant making the box taller (to make room for the TV) – moving it to the side would reduce the overall height of the case.
· I’d use bronze bushings (or, even better, sleeves made from UHMW plastic) instead of the pillow bearings. This would reduce the width of the case and still be plenty strong.
· Finally, I would have invested in a decent metal-cutting hole saw so that I could slip the frame arms over the pivot rod and weld it in place. Welding the frame to the bottom of the rod created some movement and clearance geometry that was difficult to resolve.
Step 7: Questions & Follow Up
Let me know if you have questions – happy to share my experience (and misteps!) if you decide to build one for yourself.