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TV Cabinet lift motor which is best? Answered

Hello Everybody

New to Instructables and happy to be part of the community. I'm a hobbyist wood and metal worker so this is a new type of project since it requires a little more engineering and electronics that I'm not used to. Currently building a TV cabinet for my master bedroom that will serve as a footboard with a TV lift mechanism. As you can see in the images it's a simple construction of 2 rails with drawer slides an angle iron frame with a rear plate (holds TV) and an 8mm ID pipe that houses an 8mm lead screw attached to a motor at the bottom. At the base of the frame, there is a lead screw nut that will be welded to the frame acting as the contact/lift point for the lift. The frame with tv weighs around 35lbs.

My question for the community is what type of motor would work best to handle the following

- Weight
- Lock into place (or be able to hold the weight)
- Needs to be reversable.

I looked into stepper motors and gear dc motors but don't know enough about the subject to make an informed decision.

Thanks in advance for any help.

Discussions

0
amachinetech
amachinetech

24 days ago

So here is a thought. Get a linear actuator from an old 80's vintage satellite array like this one.
https://www.summitsource.com/Venture-18-Inch-Linea...
It is self locking, runs on 24 volts, and should be long enough to so what you need to do. Also if you use standard all thread for your screws it is more or less self locking anyway. You wouldn't need a break or any of that as the friction in the nut will keep it from moving. I made something like this that dropped from the ceiling but used a repurposed garage door opener as the movement with a screw drive. The reversing of that AC motor was a bit tricky but with two relays connected to an arduino connected to an IR reciever I set the thing up to drop down from the ceiling when I turned the TV power on. Still have it and its been working good for about 3 years. Check with a garage door opener company, they throw them out all the time you may get one for cheap or free.
Good luck
A machine tech

0
amachinetech
amachinetech

Reply 23 days ago

A little bit more on the motor part for your learning. A DC motor is the easiest to reverse as all you must do is reverse the wires to change the direction of the motor. What manner of control are you thinking to use to raise and lower this. It can be done with a simple switch but you will need to either be very careful opening it with a self returning switch or create limit switches that stop the motor when it is fully open or full closed as a screw drive is very strong and will have the power to tear the cabinet apart if it maxes out with power applied. Some AC motors can be reversed if they are built to be. The garage door opener motor is one of them. Another motor that is reversible is a sewing machine motor. They are a brushed motor and normally are fed 120 volt AC power. With AC power they only spin one direction. They are known as a universal motor and can be fed DC power as well but they still need 120 volts. You will have to use a bridge rectifier to make DC out of AC. How deep in the weeds do you want to get to make this. Many ways to get there all depending on your tolerance for learning electrical theory.
Here is another instructable to get you started on the theory that you need to succeed with this.
https://www.instructables.com/id/DIY-Relay-switch-motor-controller-Arduino/

0
0ne4all
0ne4all

Reply 19 days ago

Thanks for information all very helpful!

0
Downunder35m
Downunder35m

24 days ago

It mostly depends on the thread of your rod.
Is it just a threaded rod? trapezoid, rounded, maybe even a double thread?
If it is the type of rod you would use in a milling machine or 3D printer than I would suggest to use a simple geared motor.
Like these RS555 based motors with screw on reduction box.
If you don't have any stopping mechanism to prevent the TV from slamming down I suggest to use a gear box with a worm drive as they are basically self locking.
Prefer the metal version over plastic.
If you don't mind a bit of extra work you can also salvage what you need from a 12V battery operated drill.
They come with gearbox and all you need.

0
0ne4all
0ne4all

Reply 24 days ago

Thanks for tips never thought about a drill!

0
Downunder35m
Downunder35m

Reply 22 days ago

Most people won't consider them for anything but drilling.
However, they make really strong drive systems and some models even comes with a manual speed control.
I always keep one or two broken ones, at least the vital insides for just these odd jobs ;)