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[on:]

Is it possible to use the following components without a microcontroller?

RF Transmitter
RF Receiver
Photo-Interrupter

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.

[Reply #1 on:]

That should work. You could use a simple 555 timer chip at the receiver end to insure a minimum length buzzer duration.

Lefty

[Reply #2 on:]

What happens if/when the receiver tunes in some other 315 Hz source?

[Reply #3 on:]

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.

[Reply #4 on:]

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 ...

Or thruhole parts board to do the same
http://store.nkcelectronics.com/arduino-runtime-board-rev-b.html

Need AVR ISP, or Arduino set up like one, to install a bootloader, then can download programs via serial interface.