Thread: Motor with dropping line

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I think I've seen this sold somewhere but haven't been able to track it down. I believe there is a motor for sell that consistently runs and drops a string up and down. So you can hang a skull or something. I seen that Spirit sells something called a "Spinning Motor set" but this spins and drops. I'm looking to hang something about 10lbs that drops up and down consistently without haveing to be triggered by motion, but doesn't spin....something with a bit of speed, something that would run for a few hours. Anyone know?

Wouldnt a drill motor with a flip flop relay work for that? I did a spider descender rig and thats how I did it.

Did the drill motor make a lot of noise? How did you control the line/string?

Not at all without load drill motors are pretty quiet, and the nine spiders it descended were not that heavy.
The rig was a 2x4 frame 8'x8' shelf brackets added support on all four corners
along two opposite sides I drilled pilot holes and put 8" long bolts every foot (extra length sticking inside)
PVC pipes were held into the frame by the bolts, the PVC pipe was about two inches shorter than the frames interior. the pipes should spin freely (I think I had six of them in the frame, its been awhile)
large rubber bands acted as belts between the pipes three bands went to the next pipe -and inbetween those -two went to the pipe on the other side.
if you spin one pipe, they all spin (but different directions, so as it spun some spiders were descending and others were going up)
strings were attached to the pipes and the drill was connected to one of the center pipes I think I used a plastic spool (again a big wide rubber band was used)
It spun one way for four seconds (low gear) and then the other way for four seconds. the motor was triggered by a motion sensor and sound was triggered by a motion sensor up at spider level 9the guests couldnt trip the sound
I think 12 or 13 spiders moved each time, to hide the rig beef netting went up at about the mid point of travel and the spiders went up and down through it.
with out pics thats about the best I can do for you.

Simple way to do this is to use a gear motor and a crank. Motor can be mounted with crank horizontal. Use a washer that can spin on a bolt at the end of the crank and drill a hole at the edge of the washer to tie your line too. Then the line goes out through an eyelet and down to hold your prop. You may want to use a small pulley instead of a simple eyelet because if the weight. Your prop will rise and descend based on the RPM of the motor. If you look at a FCG design it is the same only three lines are controlled.

Yeah my set up was for about 12 spiders (and I still could have done it FCG style, but I wanted to try the rubber band belt drive). a simple cam arm would work nice for one up and down movement but I dont know how you could make it descend more than twice the length of the arm. So you would need to increase the torqu quite a bit if you want a long length of travel.

I read your drive idea. At first I was confused until I read it again. So you did have a timer to reverse the motor. I take it since without any limit switches if the string wound up too far the rubber band drive would just slip. Can I assume you were actually using an oring as opposed to a rubber band?

You know your drive is really a neat idea. You could use it for a FCG. Could actually add some variety in the movement. Especially if you used different sized pipes. I am thinking of putting a FCG above the peak of my house. I want to drive it from behind the house. I was going to buy three of the cable drives motors and run them at different voltages and use limit switches to control total movement. But your idea is actually easier. By using a friction drive for the main pipe and the other pipes getting their drive from that pipe, I can see a real randomness of movement. Not to mention that I think all I will need to do is make some hard stops for the cables and trust that the friction drive will slip if a limit is reached before the motor reverses.

Cool idea.

No, I used rubber bands, they functioned like belts, I think the O rings would slip to easy the wide rubber bands held pretty well. When your setting it up, just see how much string gets let out from one revolution and time it, If the timing is off I just had a spider flopping around the PVC then I gave it more string.
Pretty simple, its also easy and cheap to play with.

i like the pvc pipe idea

A little different with the FCG. You would not want the cheesecloth wrapping around the pipe. Plus your drive will be a long ways from the ghost. Like 30 feet away. Your drive will be mounted on the ground. The cable or likely monofilament will run from the drive to elevated tensioned cross cable with small pulleys spaced at the head and two arm distance for a large ghost. What I am going to attempt to do is make the hardware as invisible as possible. I intend on erecting tall poles at each end of the peak of the roof. So only the cross cable and pulleys will be in view. It is just an idea at this point. Mounting the poles will be the big challenge.