Hey everyone! Love the forum, I've been a lurker for a bit too long to be honest!
Anyways, my name is Stuart- I'm a technology student at the University of Glasgow. And like I'm sure a lot of you guys have done, I've recently started getting electronics lectures, tutorials etc. So I have a VERY basic knowledge but I'm eager to learn (hence joining).
I was actually wondering if anyone here could give me a hand with a project I'm working on just now, it should be REALLY simple for you guys looking at some of the depth that some things have gone into!
I'm currently designing a clock in my design class, and we have to make a working prototype of our model. The design that I have is basically a laser like >>**broken link removed**<< one which is on a unit on the ceiling which slowly turns, the time is then indicated by where the laser dot is pointing to on the wall.
The problem I have had is that clock mechanisms are very fragile, and dont have enough torque to turn the weight of the motor round. So I decided that a DC motor would be far better to do this. The problem I have however is that they turn severeal hundred revolutions per minute! Not the 0.08 revolutions per hour that I need it to do in order to tell the time! Now I know that if you half the voltage going into a stepper motor, it halfs the RPM. So could I just have a circuit containing only a power supply, a big enough resistor, and a motor and set the speed from that?
Because it is only a prototype, it does not need to extremely accurately be able to tell the time, however I cant have it spinning a laser round at 200rpm! I just need to slow it down enough to give our lecturer a picture in his head of how exactly the product would work.
Someone suggested a stepper motor to me, but are they not very expensive and do they not need to be computer programmed?
Thanks for reading guys, any help will be really appreciated!