How to rotate a motor on a timer

Hi everyone,

Im a university student at the moment and my year has been thrown into the deep end by expecting us to come up with a feasible design and build it from scratch.

One of my designs involves the use of a motor which i havent really got much experience on. I was wondering if anyone with a beter knowledge be kind anough to pls explain to me how i could get a small motor to rotate once every hour or 2, depending on the time i choose? Can i even Use a timer to operate a motor?

Something long the lines of opening a door flap/pet door once every 4 hours or opening a can lid every 2 hours.

What type of motors can i use?

Any help or advice or a point in the right direction would be much appreciated.


Cheers

[User comment deleted]

you can look into building a counter that resets at 2 hrs and triggers a switch for doing whatever you need to do. a secondary timer can be set to the length of the time you need to hold the door open when the first timer tiggers.

The first two answers here are good starters
.
May I first ask what you are studying ? If it is electronic engineering, then you would be expected to invent a primarily electronic solution.

A couple of possibilities:
1) 555 Timer IC in astable mode circuit provides a pulse at a certain rate.
(There are now some 555s specially for long intervals.)
Divider circuit (if required) to reduce the rate.
This output is amplified to provide pulses to a stepper motor controller chip, which drives a stepper motor.
Stepper motors come in a variety of `steps per revolution', but the output can also be geared down mechanically.

One timer circuit can control the overall timing of events, triggering another timer circuit providing power to the motor for a certain period, or being switched off when a sensor indicates a movement is completed

Alternatively (more simply) the timing circuit can then control (e.g. via a transistor) power to an ordinary DC motor until a limit switch cuts it off when a task is done.

2) The microcontroller solution (a much steeper learning curve, but worthwhile) could use timing loops in the program, and also gives multiple possibilities for input sensors and output devices controlled from the one programmed IC.

The Picaxe microcontroller is the easiest to learn and use as it is programed in BASIC. It comes in ICs from 8 to 40 pins depending on how many inputs and outputs you want. It is also possible to include a real time clock chip if you want precise timing.

Primary sources for Picaxe chips and info:

In the UK:
Information: rev-ed.co.uk
Supplier: techsupplies.co.uk (= shop for rev-ed)
Technical Support Forum: www.picaxeforum.co.uk

In the US:
http://www.phanderson.com/picaxe/ Supplies both the chips and helpful information.

Uses and embeded micro and stepper motor or use an ordinary motor with revolution sensing or use embedded micro with servo motor control implementing timer interrupts You can count timer interrupts and decriment and hour being of course 60 minutes or you add one minute every x amount of instructions when you timer overflows

Quite easy to do or use a realtime clock ic and use hardware interrupts Or use an atomic clock coupled to motor drive circuitry

see link below
http://www.joejaworski.com/wwvb/