guys i need your help.
i would like to improve my security system whereby when you tap down the door handle you activate the accelerometer connected to it then a beeping sound would be heard inside the house. this would monitor the presence of a person by the door.my problem is i have never used such gadget, the accelerometer is analog connected to the Pic 16f877. anyone who can help me is welcome of how can i go about this project.

 

Quite easy to use.

the accelerometers data sheet should have a few circuits to show off functionality.

Have you chosen an accelerometer yet?

 

retched

Thanks for your quick response.i havent choose the accelerometer, maybe you can help me out on which is the best one for the PIC16f877.

lihle

 

Well, you need the best one for the job, not the uC.

Any whoose, have you considered a capacitive touch detector? That way they only need to touch the doorknob, not move it.

Give this a read:
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=167

 

retched

thanks man.but my problem might be that the whole system uses the PIC16f877 so i wonder if the output of the capacitive detector can be an input to the PIC. if yes then will try to look at the link you gave me.

lihle

 

or possibly use a tilt switch, very robust, and would not be affected by stray capacitance as the capacitive touch sensor, and would require less wiring than an accelerometer (Only 2 wires are required for a tilt sensor/switch)...

Read this to learn more about tilt sensors >>> http://www.ladyada.net/learn/sensors/tilt.html

B. Morse

 

I will agree with the tilt sensor.

That would be simple.

Vcc to the switch, and the switch to an input. Its that easy. when you have a HIGH on the input pin, you know it has been moved.

 

retched

thanks man i hane read more about is so simple i will try to get it immediately.

lihle