Programming motor to run for 10 sec?

[venturiandog]

Hello, this may not even be a robot question.  But thought I would turn to your guys for direction and help.  I am trying have a photoelectric sensor be my on switch, and have it run an electric motor for about 10 sec., then shut off.  Could anybody help with direction on how to make this happen.  Do I need a micro controller?  Not sure where to start to look.  Thanks for any help!

Tony

[Billy]

You could use a microcontroller but you don't need to.
You can buy a relay that has that timing function built it.
As you may have imagined, they are called timing relays.

[venturiandog]

Billy, thank you very much for replying and helping me!  I am designing a mechanical device but did not have any clue how to do the electronics to run my motor.  Thank you again!

[mklrobo]

  Hello!
I agree with Billy, that it would easier and more efficent to
buy a timer that takes an input from a sensor.
Otherwise, if you build your own, it may be described like this;
The sensor feeds into an Op Amp that acts like a comparator,
looking for the voltage level to change when the sensor is
activated. the logic level comparator activates a transistor,
which, in turn, activates a 555 timer, acting like a one-shot
flip-flop.(timer) The timer activates a control transistor that
grounds the control side of the relay; the Normally open
contacts of the relay are used to power your motor, for the
time generated by the 555 timer.
I would probably use a pre-made timer with your sensor.
Good luck!!