OK- designing a system to raise/lower my plasma tv

[deadmeat]

You guys seem to be a whole lot more technically adept than I, so here is my question.

I took the dive and have purchased a 42" plasma TV (it is already purchased, so I don't want to hear from those ofyou who are going to tell me I made a mistake)>

I have a fireplace in my living room. Over it ( in a deep nook) is all my Stereo equipment, DVD player, and DVDs and CDs. I want to mount this TV on a wire system IN FRONT of this nook sort of like one would mount a painting over a fireplace. The catch is that I want to rig up a pulley/electric motor system so that with the flick of a switch I can raise or lower it. The goal is to lower it to sitting eye level when watching it, raise it up out of the way when not.

I cannot for the life of my find a motor that can raise 100lbs that is reversable, and that has low enough RPMs that it would not smash the TV. I know there are motors like this for applications, such as raising and lowering movie screens and such. ANy ideas out there? I think even if the motor was moderately fast (like < 100 rpm) I could rig up a pulley system to transpose that to slow movement.

Help, advice appreciated. Mocking is OK too ... I'm used to it.

 

[HVAC]

You are correct about a direct motor drive. You need gears in between the motor and the wire.

Why don't we look at vehicle winches or some smaller duty winch. They are not real fast or some are variable speed. Some are reversible.

Yep, I think you need a wench.....er......I mean winch.

 

[Rastus]

Just watch a couple episodes of Monster Garage and your answer will come to you.

Do a google search on servo systems and PLC's. The stuff to do what you want can be had off-the-shelf.

 

[deadmeat]

THanks to both of you. I actually thought that if nothing else I could easily adapt a screw-drive garage door opener to fit my needs... any other ideas, including links to the type of equipment I would need, are appreciated.

 

[Amorphus]

why not just a DC motor with a decent amount of torque, and use something exploiting gear ratios?

as far as I know, DC motors are reversible jus tby revering current flow, and having a very high gear ratio would make it slow, but very strong.

 

[deadmeat]

Any suggestions on where or what to get? I have never done anything like this before.

 

[deadmeat]

Any suggestions on where or what to get? I have never done anything like this before.

 

[davesaudio]

you know there is commercial product
auton (sic?) that does this
leno has one to pop up that tv for video clips

 

[davesaudio]

want to do diy?
old gm power window motors and cranks

 

[deadmeat]

great idea! Thanks!

 

[TheJ00]

Hello! Maybe you can use electrical cylinders. I don't know the real english name for them but they look like hydralic cylinders but contains gears and a DC engine instead. If you are intrested I can look up the real name for them.

 

[deadmeat]

If you can give me any information, like where to find them, I would appreciate it a great deal! You guys rock.

 

[TheJ00]

I will do that after this weekend

 

[Bleep]

Have a look at this SITE
They have a lot of stuff and may have something that would work for you.

Bleep

 

[AEB]

i dont know if you watch the ozbornes but tehy have a plasme that when it is lowered look slike a table and raised you can see the whole tv im not sure if its seomthing from the floor or something like what your looking to do. you could always use wires to suspend it like a projector screen

 

[TheJ00]

The thing I talked about is called actuator in english. But I don't know where you can find them. Maybe if you search on the net.

 

[Def]

See if you can find a decently powerful electric motor that works off 120VAC, or maybe even 220VAC if you think you can run a direct line. 1/4HP should be more than enough. Regulators get problematic after a long time in my experience, so best to avoid DC if at all possible.

Make sure it is solidly mounted, then I'd use sprockets from a bike to get the best gear ratio possible. Think small small sprocket on the motor and really large one on the one accuating the wire. Make sure the wire is fairly robust as well.

All in all, if you just laid down the change for a 42" plasma TV, you might just want to buy something prebuilt for this application or one like it since it seems you aren't exactly hurting for spending cash and really seem to value your home entertainment setup. Your time has got to be worth more than it will take you to build one of these things from scratch(I'd guess at least a whole weekend if you had all the tools, welding equiptment and the know-how, at least a week or two if you were going at it first try).

Your call.

 

[kaizersose]

I have to agree with def (above) on this one--i built a number of linear actuation machines in college and none of them were as easy or successful as i thought.

if you are truly dedicated to doing it yourself, which is completely understandable, i would go with the wires. this was actually done on a tv show on the discovery channel called "monster house". they were modifying a house to give it a mid-evil look and they had the tv on a platform that raised and lowered using a giant hand crank like the type used on castle drawbridges and gates. this crank could easily be replaced with a motor. dc motors are way more powereful than most people realize.

you will need to gear the motor down (more torque, less speed) using a gear reduction which will suck to build. another option is to look for a dc gearhead motor which has a complex set of gear built into the head of the motor. you will need to find the torque necessary to lift your tv and then choose the motor for you setup.

the more i think about this, the harder it is getting. you are going to need bearings, metal rods, motors, wires, a whole lot of tools and a ton of experience. this is all just to build the mechanical part--the control system to do what you want is another strory (you want position control which means you will need to write software). i would look for a stock solution.

 

[Yossarian451]

I have a garage door opener that I just took out of my house and after looking at it and thinking about it I figure taking something like that you could rig up a system with two rotating gear/pulleys on both sides of the tv with the motor in the middle at the top and just use the motor to pull a wire attached to the middle of a single wire going from each side of the tv and ove the pulley and to the next pulley and the other die of the tv sort of a:

()----*-----()
| . . . . . . . .|
| . . . . . . . .|
{ Plasma }

edit:ignore the periods it would let me just have spaces

the star being the point with another wire which is attached to the motor could pull up the screeen evenly. basically mimicing your garage door opener. I wouls suggest maybe putting the motor out of sight, maybe in the ceiling and an elbow to direct the wire. The sears garage door opener I have has a knob which adjusts how much the wire would be pulled in so you could make sure that it wouldn't pull it through the roof, and just have the bottome be at eye level. Maybe not cheap if you have to buy a new opener but if someone you know had the same problem I had, which was that the motor works fine but that it went to a plastic gear which wore away, you could probably find one cheap. also you would be able to adjust it wirelessly with the opener. Have fun with whatever you do, it seems like a really interesting idea.