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Need to Slow Down a Display Motor

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drabain

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I have a DC motor that runs off a 1.5v D-sized battery. It is a motor that is inserted into a tube and has a connection peice that allows for 3 posters to be attached and they spin when the motor is turned on. The motor turns too quickly to allow for the info to be read. How can I slow it down or (even better) fix it up to spin a 1/3rd of a turn, stop for a about 30 seconds than turn another 1/3rd and stop for a about 30 seconds, etc?

Thanks
 
Are you saying you want to slow down a motor?

Read here.
**broken link removed**
 
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Yes...either slow it down or have it spin in 1/3rd revolutions and stop for about 20 seconds. At the current speed, it spins too fast to propoerly read the display.
 
The standard solution is to gear it down so the output of the gearbox rotates once for every 3 turns of the motor. Increases torque, lowers speed, and decreases motor current and heat.

Or you could feed it 1/3 the voltage or PWM it at the current voltage but with a 30% duty cycle. BOth of these methods however, decrease speed and decrease torque (possibly to the point where it is too weak).
 
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How many batteries does it run off of?
 
Really don't have time or resources over here in Bermuda to build a gear solution. I would really like a "out the box" solution if possible that I can order and stick between the battery and motor. Motor is already geared, etc and is in a sealed plastic housing. It is really not possible to add gears to this solution (will post a pic later) and I need this about 2 weeks.
 
Try putting a diode rated for constant current at 1.5 or 2X the motor's peak draw inline with the battery. That's a quick and dirty way to blow off a little power. Add more diodes, you'll get a slower motor, keep in mind this power is lost as heat in the diode itself depending on the current, so plan accordingly.
 
You could use a couple 555 timers to have the motor run for a given time and then stop for a given time. The first 555 would be connected as an astable multivibrator with a period of 20-30 (plus the period of the second 555) seconds. This would trigger the second 555 connected as a monostable multivibrator (one-shot) with a period sufficient to run the motor for 1/3 turn. The monostable will need a transistor amp to power the motor.

You can Google "555 timer circuits" for many references on how to design the circuits.
 
Just throwing together a concept. A 555 astable and three limit switches to stop the motor at the three positions and restart it after a delay. Sort of reminiscent of the windshield wiper delay circuits. ;)

Ken
 

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Try the diode first =) Can't beat a penny part you just stick in vs trying a couple timer circuits you may or may not be familiar with.
 
Try the diode first =) Can't beat a penny part you just stick in vs trying a couple timer circuits you may or may not be familiar with.

As Sceadwian says, try the diode first. Pop into the electronics store on the corner of Church St & Washington Lane and ask for 1N914, 1N4148 or something from the 1N400X series, they should have them. You could also have a chat with the tech (older guy about 5' 6") he was always helpful when I spoke to him in the past.

HTH.
 
If the motor is running off of a D-cell, a 1N914 or 1N4148 might be a little too light on the absolute maximum If. Espacially for the motor start-current. The 1N400x would be a whole lot safer.

ken
 
Mickster - That store you refer to is Radio Shack and it closed about 3 or 4 years ago! LOL! Hence my need to do soemthign quick and dirty becuse I need to order the parts to come to Bermuda. The cleaner and less hassle it it, the better.....
 
drabain....PM sent.

EDIT: PM only contains contact info of others, not project solutions.
 
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