TV lift - Simple gear Motor position (no feedback)

Using Arduino Project Guidance
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TV lift - motor positioning and logic

Hi all,

I modified a simple up and down TV lift to also rotate (with this motor : https://a.co/d/fZlCvtd)
and tilt (with this actuator : https://a.co/d/bO2NCkS).

It works great, but unfortunately I have 3 separate RF remotes for these so use is clunky.

The lift is hidden inside a box, so when it’s time to close up I have to ensure the TV is back to the correct position and tilt before the lift goes back down.

Using Arduino and some L2989 motor drivers I would like to program the motors to do the following with one button press when it’s time to put the TV away:

press button to lower TV

  1. Tilt TV to orginal position - which is to retract the tilt actuator fully.

  2. if TV is not center spin motor to move TV to original center position, which will be decided by either an infrared sensor switch u have lying around,and/or the motor position eedback if it gives any (don’t think it does)

  3. Check sensors again, if switch is closed, and tilt actuator is fully retracted then lower TV all the way down.

So far I have a test actuator working via a L2989 and some arduino code - just extending and retracting so far along with speed changes via PWM.

My main question: what is the best way to ensure the motor returns to the correct position (limit switch?).

Would love to hear suggestions on how to proceed on this project, I think it’s feasible and am excited to work on it. Should I replace the motor with one that offers positional feedback (I assume they exist) or continue with the turn until a switch is triggered method?

Thanks!

Videos of tv lift here:

https://www.flickr.com/gp/193106459@N07/swqSCv1YK6

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Just use a microswitch.

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Thanks. What kind of microswitch and where do you think I should mount these?

4

Google microswitch, find a small and cheap type, look at the outline drawing and it should be relatively obvious. You just mount it so it's activated as the TV moves to it parked position.

5

In just the "neutral" position of all axes, ready to lower the TV set.

1 Like
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Thanks. I will do research more on micro switches now.

The TV rotates in both directions past the neutral position. Would a microswitch physically impede this movement? Obviously I want the motor to stop when the switch is activated when putting the TV away, but also be able to move freely it in either direction when in normal use.

Thanks again.

7

Mount something which adds a bump to the moveable part - a screw head, or whatever, in the center position such that it actuates the switch as it passes by. There are switches with rollers and other means of actuation available. Do a search on 'microswitch' and select 'images'.

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This is generically called a "cam". A bump or a depression in the cam is a position indicator to the microswitch.

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Doh!   Good catch!

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