Circuit design required

[Pranav Jha]

Main Question or Discussion Point

hi everyone! for my science project, i want to create a circuit which automatically opens the lid of a dustbin when a person passes by the dustbin. Is there a particular type of circuit that i can use to accomplish this?

 

[likephysics]

What do you mean by particular type of circuit?
The general idea would be something like -

proximity sensor --->Microcontroller--->servo motor driver-->servo motors.

Proximity sensor, like an ultrasonic sensor or infrared sensor etc would sense the person and send a signal to a Micro.
Micro would then drive a servo motor thru a servo drive circuit. The servo motor would open the lid.
You could eliminate the Microcontroller and wire the sensor directly to the servo drive circuit.

 

[Pranav Jha]

haven't worked with servo motors yet. Could you give me the name of sites that would be a good place to start off one's experience with servo motors?

 

[Carl Pugh]

Servo motors are generally more difficult to work with than DC motors. If you are trying to keep this as simple as possible, use a DC motor and limit switches.
For people sensing, Fresnel Lenses are frequently used.
Doing a Google search, this site came up. Not familiar with them, so cannot guarantee that they are OK.
http://www.epanorama.net/sff/Alarms...otion_Detectors/Infrared People Detectors.pdf

 

[schip666!]

Even simpler than a motor, use a solenoid from your old washing-machine to open the lid.

Also look for Passive InfraRed (PIR), like your porch light thing-a-ma-bob, and close range IR sensors to trigger the thing. Once again I recommend sparkfun.com ...