Controlling a DC Motor

[diablo1]

How would I go about turning a DC motor 360 degrees with the click of a microswitch each time?

 

[Noggin]

You'd need some type of encoder wheel, like those found in an old ball type mouse. Shine an IR beam through the wheel, apply power to motor, count number of times the micro sees a flash.

 

[duffy]

I think it's easier than that, one switch on the motor and an edge-triggered flip-flop.

 

[be80be]

You have to be able to stop the motor if It is a slow gear motor you could use a cam on the shaft and dpdt switch. If the motor is fast you would have to use You'd some type of encoder wheel like Noggin said with a h-bridge that can brake the motor.

 

[diablo1]

please elaborate i dont know what this means

 

[be80be]

Some thing like this would work. The switch is powered to set the motor the first 360 when tripped
it will stop and wait for reset for the next 360.

 

[Ubergeek63]

You have to be able to stop the motor if It is a slow gear motor you could use a cam on the shaft and dpdt switch. If the motor is fast you would have to use You'd some type of encoder wheel like Noggin said with a h-bridge that can brake the motor.

if the motor is fast he would need a good controller since while it would stop it would not be clean, most likely having a damped oscillation every time it stopped.

If he is very unlucky he would end up with a completely unstable system. The amount of losses in a typical motor system makes this situation virtually impossible.

Dan

 

[diablo1]

airsoft guns use a unique technology. their gearboxes are turned by a DC motor that when you pull back the trigger you close the circuit but some mechanism only allows the circuit to be closed for a certain amount of time to have reach the desired revolutions on the DC motor.

 

[Nigel Goodwin]

I seriously doubt it works that way, it more likely just uses a limit switch - timing just doesn't work, it's far too inaccurate.

 

[be80be]

Like I said it's hard to control a fast motor. That's why there are steppers. A slow geared motor you could use a cam and a switch to to stop it. Like Nigel said

timing just doesn't work, it's far too inaccurate.

What I showed you will work the motor is turning about 100 rpm or less it's not the best way but it is easy to do and the motor can keep going fwd after the stop.

 

[duffy]

The pure timing thing doesn't work, tried it many times.

 

[be80be]

Look at this [embed]http://www.youtube.com/v/W4QkR3igNkE&hl=en&fs=1[/embed]

 

[Nigel Goodwin]

Nobody likes a show off

 

[diablo1]

i dont see it

 

[duffy]

Dude, it's a CAM! He's showing you a cam switch!

 

[diablo1]

yea thats what i want it to do but much faster and with a click of a microswitch button, thanks for the vid

 

[be80be]

Nobody likes a show off

I wasn't being a show off I was just showing how it works sorry if any one thinks that way.

 

[be80be]

You can go faster about 3 times then what that gear motor is turning.

 

[duffy]

Nobody really thinks you're being a showoff, and some of us realize you are obviously trying to help illustrate the operation of a fundamental and important gizmo.

 

[be80be]

See I got layed off and thay close down where I worked so i ended up with a basement full
of junk to play with and lot of time to do it. I was just trying to help.
I think he wants to load his gun with a push of a button