Basically, I want there to be two units. One with the Transmitter and Photo-Interrupter. The Photo-Int will be mounted next to a door. The door will have a small peg that will break the sensor while closed, and will uninterrupted the sensor when open. When the sensor is uninterrupted, I want it to trigger the RF Transmitter to send a signal.
The RF Receiver would be in a remote unit. When it receives the ping/signal, it would trigger a speaker on the unit to buzz for 2-5 seconds then stop. Maybe even flash an LED.
Id rather not use a micro-controller for this, so I am just wondering what my options are.
CrossRoads:
What happens if/when the receiver tunes in some other 315 Hz source?
It is standard when sending serial data wirelessly to send a packet of "clearing" data beforehand - it is commonplace to send data before your packet such as repeated 'U's - the reason for U's is because of it's binary bit pattern - 01010101. I send this 4 times before I send any data.
My receiver then checks to see if these U characters have been received, and if so it then accepts the incoming data, otherwise it ignores it.
Ok, something has to create that pattern, and recognize it on the other end to be ready to act on the real signal.
Something like a Mini-uino could do that for you.
$2 for a board (I have 50 boards arriving from iteadstudio any day now, 37 are spoken for),
resistor, couple of caps, crystal, ~50-60 cents total?
$3.83 for uC, http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ATMEGA328-AU-ND
3 AA battery pack and some programming for virtualwire to send a message, you're on your way ...
