Need to build reverse and forward motor with custom speed

[BhushanSethi]

Hi,
I need a motor that can rotate forward and backward with speed I want. Basically, I want to pull a rope (with motor) about 6 inch in 1.6 seconds and release same about 6 inches in 0.8 seconds.
Sorry, if requirements sounds weird but this is for a project I am trying to make for daughter's therapy.

I believe I would need a motor, some timer chip and ropes. Can you please guide me where should i buy and what should i buy for this project.

Thanks

 

[3DDave]

How hard does it have to pull? Why does it have to rotate?

I would look at a linear actuator, a motor driver, and an Arduino to control the driver. You'll also need a suitable power supply and some way to mount motor.

 

[MikeHalloran]

OR, you could use a crank with a 3 inch radius, and a motor that can run at two speeds, but it doesn't need to reverse. It's possible that the load applied could slow the motor down a bit on the 'up' stroke, and the motor will naturally go faster on the 'down' stroke if the load is constant in direction and/or is removed for that part of the cycle. So, a motor that nominally rotates a full turn in 3.2 seconds, or 18.75 rpm. Motors don't go that slow easily, so a small gearmotor is indicated, with a small motor, size depending on load, which is so far unspecified.

The rope can have an eye and a thimble over the crank journal, and if the rope is long enough, you don't need a slider, just a few guides.

You have to be _really_ careful if this device contacts the patient.
You probably need a local engineer with some specific experience to guide you.



Mike Halloran
Pembroke Pines, FL, USA

 

[GregLocock]

You might experiment with a cordless drill.

Cheers

Greg Locock


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