This was a little project I started about a year ago. I have had a few people ask me for more details so here it is.
First of all - WHY?
For me this started as a bit of a fun idea. I usually have a few projects rolling around in my head, if they roll around for long enough without me finding a good enough reason not to do it then usually I think its worth giving a go. Whats the worst that can happen? A broken TV and a big hole in the ceiling.
A major factor is that my wife and I both don't agree with the idea of having the TV as the center piece of the house. The idol which many organise their space around and sit down to worship at each day. The default thing to do when you don't feel like doing anything. The kids pacifier so you can get things done when you need to. That being said, we don't disagree with TV. Before this we would often use a laptop to watch a movie or show at night. And this was a nice relaxing thing to do together on occasion. Then the laptop died.
We didn't have a TV at the time and we didn't really have a good place to put one without majorly re-arranging our living room. The back wall is a bit far away and our house is too small to be putting lounge chairs in the middle of the room.
So I convinced my wife I could fix all this by making the TV come out of the ceiling exactly where we wanted it. Then during the day, or when we didn't want it, I could make it go away out of sight out of mind. To my surprise she trusted me.
How.
So I got to work. Firstly I modeled it up in 3D. I'm not great at sketching and this was a good way to tie down those ideas that were rolling around and to make sure everything was going to fit in the ceiling space I had to work with.
I bought the stuff I needed (including the TV). And started putting it together. Here's a Video showing how it went together.
It's driven by a garage door motor, supported by steel cables, and directed by drawer slides (3 sets attached to eachother to get the extension). The counter weight balances the weight of the TV to reduce the load on the motor (it was struggling without it). Since uploading this I also added a flap (with foam for insulation) which closes over the hole when the TV is in the down position. I also plan to add a box enclosure up in the ceiling to help keep it sealed and cooler when in the ceiling. Though on really hot summer days I might just keep the TV down.
The garage door motor is a Chambelain HandyLift Plus. This worked well because it has programmable stop limits (which it remembers even if it looses power). It also has a learning over-torque function which will stop the motor if the torque is higher than normal (I.e. if the TV gets jammed or hits something on the way down). This motor comes with it's own remotes. The TV will automatically stop in the up or down position or you can press the button again to stop it at any position.
The drawer slides are 125kg rated x 500mm. With three sets together I could get 1.5m extension compressing down to 500mm. I needed this much compression because of how it is mounted to the TV and the limited space in the ceiling. If I had mounted all the way down the TV I could have used 2 sets of 750mm slides to get the same extension (this would have been more rigid). I got the slides from here http://www.indrub.com.au/hardware/dra... I used stainless steel wire rope (2.0mm with 7x7 strands) for the cables. This is rated at 254kg per wire. I also used turnbuckles to give some fine adjustment of each wire. http://stores.ebay.com.au/lowcostwire/ I used 90mm plastic pulleys (designed for gym equipment) mounted to a 10mm shaft, stiffed by some 50x50x4 angle welded to the shaft with cutaways for the pulleys. You can get these off ebay. I was able to get the cable real (plastic) for from an electrical supplier near me. I also mounted deep grove ball bearings in the cable real to take up the difference in diameter to the shaft.
What about....
The heat and dust in the ceiling space - I thought this through right from the start. The TV specifications says the maximum operating temperature is 40C. It gets to over 55C in my ceiling during summer. But the TV will be off when its up there so its not operating in that temperature. Also I know a few people who have TV's mounted in out door areas (including my neighbor). I figure the ceiling isn't any worse than outdoors. I was planning to build an enclosure around it in the ceiling but now I wonder if that could make it worse (keep the TV's heat in a confined space). In any case I accept that this might shorten the life to the TV, but this is a risk I was willing to take. During really hot days I leave the TV partway down so that the important stuff gets some aircon going past it.
Attaching cables - The only cable going to the TV is the power cable. Everything else I stream or cast to the TV over Wifi. I did however leave an extra pulley up to top so I could connect another cable in the future if I want to. I don't think I will use it.
People running into it - So far no one has run into it. Its a big black thing in the middle of the room so its hard to miss. We also only usually have it down at night to watch a movie or show then we put it straight back up. The drawer slides are rated for 125kg, so you would have to be running pretty fast to break the rails.
I realise these are issues some people might think differently about. I'm not encouraging you to copy me. I've had this up for over a year and don't have any regrets so far. I like to do things differently and like to design and build them myself. If that's not you then please don't attempt this.
If you got this far - thanks for reading. And sorry about the mess in the house. Things were moved around a bit while I was cutting the roof.