PID to start up a pc

Hi, i am doing my national certificate in engineering and really need some help in my project. I've decided to design and build a a passive inrared sensor possibly using segmented mirrors to power on a pc. This will only be required to turn on the pc and not to turn it off. I think I will power the detector via a the usb port. I have a few questions that i would be very grateful if anyone could help me with...

1. Does anyone have a similar circuit diagram or a site that would have?

2. Does anyone have a site that sells the necessary components?

3. If i were use segmented mirrors, can i still use a translucent window to prevent accidental activation from things like insects?

I wasn't aware that the USB could be used to power on a PC.

There is a Microchip PIC USB kit that is small and easy to use. I've used it to make some USB peripheral devices.

Many keyboards have a power button or wake from sleep button. You'll need to use a USB based microcontroller or pull the controller out of a keyboard and put the wake key across the PIR relay.

Depending on the motherboard you may also find the ability to wake on lan, and wake on phone ring.

Ciaran85 said:

1. Does anyone have a similar circuit diagram or a site that would have?

Click to expand...

this: **broken link removed** might help you.
The sensor itself (ir receiver, window ...) might be cheaper to purchase in any electronic eq. shop, the control of the sensor you can easily build yourself.

the "turn on the pc" part can be done easy by using the power switch connector on the mb. you just need to connect two pin's for a few milliseconds, you can do that using a transistor or small relay... the other way is to go USB and to "play the keyboard" using some uC but note that not many MB's support "power on by usb device"

Ciaran85 said:

2. Does anyone have a site that sells the necessary components?

Click to expand...

Depending on your location, there are numerous sites that sell components online

Ciaran85 said:

3. If i were use segmented mirrors, can i still use a translucent window to prevent accidental activation from things like insects?

Click to expand...

translucent window will disperse the "image" hence small sources will not trigger the sensor if you set up the gain properly


In general, google is your friend .. http://www.google.com/search?q=pir+sensor+schematic

Thanks for the advice, much appreciated