Help with moving clock hands fast

Community General Discussions
1

Hello, I am trying to make two very large projects for high school marching band props. I am new to the mechanics portion of these props so any help is greatly appreciated and extra thanks if you tell me in the simplest terms possible.

1 - A pocket watch in which the hands turn approximately one full hour in one minute. (The hands are 2.5 feet long if that is necessary information.) I have a quartz clock and hope to attach a small servo motor (or a better suggestion if you have it) to the time set wheel on the back. I also would like for the servo to be run by batteries and need those batteries to last at least 30 minutes. What are your suggestions on which servo motor to buy, what batteries will make it work and not spin too fast, and if you have a suggestion other than glue to make it attach to the time set wheel.

  1. We are also making a metronome. What motor and battery pack can I buy that will let a 6 foot “needle” on the metronome swing about 90 degrees in slow motion? Looking for it to swing that 90 degrees and back in 3-4 seconds. It needs to swing slower than and actual metronome so we do not get called out for an advantage.

Thank you for your help,
Sandi

2

Hi Sandi,

  1. To be able to properly set the hands you might either need a Stepper motor or an Encoder to know exactly where you are.
    Using a Servo will not give you positioning over more than 180deg maximum.

  2. It would be better to use a motor with a mechanical parallel bar design something like a Wiper setup in cars. You could even get a complete Wiper system for cheap.

:slight_smile:

3

Thanks for the reply!

  1. I don’t need to set the hands of the clock I only need them to move slowly around the face in one direction for about 10 minutes. I will attach the motor to the small wheel in the back that sets the clock. The wheel moves about 45 minutes per rotation and I am looking to get about 12 hours in the 10 minutes that it will be on. So… faster than real time but not so fast that it is super annoying. I am looking for a motor that turns in one direction very slowly and has a way to attach to a wheel that is about 1 cm wide. And also, the battery pack that will run that motor.

  2. yes, we have originally thought of the wiper motor but hoped to have an easier motor to deal with that can be easily attached to a battery.

sandi

4

  1. You should look at your mechanism and guess the Motor rotation (RPM) required to get the movement needed. You also need to know what kind of torque is required. Once that’s set choosing the motor and battery will be easier.

  2. I don’t know what easier it could be.