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Timer to switch on and off electric motor help

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goggs1987

New Member
Hi there

Just been browsing this site for some help (v useful site!) but I am struggling to come up with ideas for what I am after due to my lack of knowledge :)!

Basically, I am a keen photographer and I have made a dolly / rail system for my camera to slide along to take time-lapsed photography. I have just been moving it in increments by hand.

I am keen to see if anybody would know how to create a timer which would be linked to a switch, and that switch would momentarily turn on the motor and then turn it off .... therefore moving the camera in increments. Could this be possible? in an ideal world i would love if the timer could be adjustable but maybe that'd be asking too much :)! would save spending a fortune on professional camera gear!

If anyone could help / has info / could recommend parts, that would be amazing!
 

goggs1987

New Member
Do the increments have to be the same lenght?

yes preferably ... but I would assume that would go hand in hand with the rate of the timer / how long the switch is "ON" for? ............ what i am looking for is just a quick blip On and Off, so say i want to take a picture every 2 secs, the timer would tell the motor to blip and and off every 2 secs. But to be honest with you I am mainly looking for it to have big intervals, for night time photography ...... longer gaps of up to 30 secs .......... every 30 secs the timer switches the motor on then off.

re-looking at your questions though, now that im thinking, are you relating the question to how long the switch needs to be ON for? thanks for reply :)
 

Reloadron

Well-Known Member
Most Helpful Member
Basically, I am a keen photographer and I have made a dolly / rail system for my camera to slide along to take time-lapsed photography. I have just been moving it in increments by hand.

It sounds to me like it would work if you can incorporate a Precision Plain-Bearing Slide with Lead Screw that was motor driven. In a given time the motor would turn a given number of revolutions and move the table (carriage) a given distance. Maybe with an acme thread lead screw? The next option would be to drive the lead screw with a stepper motor a given number of pulses, thus a given rotation for a given distance based on the thread pitch.

There are systems like this but they are not exactly cheap. However. likely you could fabricate something.

Ron
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
If your willing to use a AC synchonous motor and even a pulley system, the errors may be tolerable. I did a similar thing, with a piece of film that had to be moved over a window and had a take-up real. Someone else derived the equation based on the need to change the # of revs as the reel increased in diameter.

It can also be done with a DC motor if dynamic braking is employed. That can be done with a simple relay. In the off mode, the relay shorts the motor. You can use two relays an have a Direction and a not enable signal.

You can also have the motor run continuously. I did this with a 555 timer, transformer and AC synchronous motor (essentially made a variable frequency drive) for telescope elapsed photography for someone too, Now you just need a way to trigger the camera in intervals and possibly stop the camera while the picture is being taken, but you may not need to.
 

4pyros

Well-Known Member
Most Helpful Member
I would use sensors at each locashoin to get it to stop at the same spot every time. Andy
 

Boncuk

New Member
Hi,

I guess precision in camera movement is not required down to 1mm with each motor start.

The mechanical drive would then use a threaded iron rod (M3 through M12 available at home markets and use a slider carrying the camera on a nut traveling along the thread.

To avoid jamming of the drive you might remove the thread and use pressure springs to press the nut towards the thread. (See attachment)

The timer should consist of two parts: Trigger circuit (adjustable from 1 to 30 seconds) and motor control circuit (adjustable)

Boncuk
 

Attachments

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4pyros

Well-Known Member
Most Helpful Member
Basically, I am a keen photographer and I have made a dolly / rail system for my camera to slide along to take time-lapsed photography. I have just been moving it in increments by hand.
With a rail system I dont think the OP should use a lead screw.
Put a motor on the dolly and use sensors or flags on the rail to stop it at the right spot.
Andy
 

Boncuk

New Member
With a rail system I dont think the OP should use a lead screw.
Put a motor on the dolly and use sensors or flags on the rail to stop it at the right spot.
Andy

I don't know the lenght of the rail system.

Using a stepper motor and apply a defined number of step pulses each time the camera has to be moved eliminates the need of countless sensors along the rail.

Having the sensors mounted at fixed positions is probably not what the OP wants. Using a lead screw makes the drive universal.

Boncuk
 

4pyros

Well-Known Member
Most Helpful Member
Having the sensors mounted at fixed positions is probably not what the OP wants.
I would use flages on the rail and one sensor on the dolly.
Using a lead screw makes the drive universal.
Yes but it limits travel and is prone to alinement problums.
Andy
 
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