Transmitter/Receiver Help

[arigid]

Hi, I have been working on a project, where a change in state of a limit switch is used, to send a signal from a transmitter to a receiver.
The receiver is to be used to just activate a buzzer.
Can this be done without using a micro!?
What kind of signal does the receiver give at the data pin.?
Thanks for any help in advance.

[billhowl]

You may try one of this remote relay switch


Mini 12V 1 Channel Way RF Remote Control Switch Relay Output for light  US$9.99

[jwatte]

Hi, I have been working on a project, where a change in state of a limit switch is used, to send a signal from a transmitter to a receiver.
The receiver is to be used to just activate a buzzer.
Can this be done without using a micro!?

Yes! Just run a wire from a battery to a "normally open" limit switch, then from the limit switch to a buzzer, and then back to the battery.

If you need wireless, then some "remote relay" function like you suggest could be used.

[Soeren]

Hi,

I have been working on a project, where a change in state of a limit switch is used, to send a signal from a transmitter to a receiver.
The receiver is to be used to just activate a buzzer.

Get a cheap wireless doorbell and activate the button via a capacitor (of say 1..10µF) and you're done. You won't be able to make it any cheaper yourself.

Check the range of the doorbell (and subtract 20..30% to be sure).
If this is for something critical, you should get a proper system.

[arigid]

Thank you for the reply guys,
@billhowl, that is actually pretty good, and i am definitely buying it.

It was actually a college project and obviously has to be more of something that you make from the parts available,
I bought the Sparkfun Transmitter/receiver pair(434MHz).
Could it be possible to hook up the transmitter, such that it takes in a digital input(limit switch), without using a micro.
And send a signal to the receiver which gives a digital output!?

[Soeren]

Hi,

I bought the Sparkfun Transmitter/receiver pair(434MHz).
Could it be possible to hook up the transmitter, such that it takes in a digital input(limit switch), without using a micro.
And send a signal to the receiver which gives a digital output!?

Yes, either use a monoflop to pulse the transmitter input high for a given time, or the same, but modulate the input with eg. 1..2kHz for that  period - A 4093 (and a few passives) is all it takes.
On the receiver side look for a signal that mimicks the transmitted signal.
If you need to discriminate in crowded air, a little more circuitry could be used to generate a more stable frequency of the modulation (x-tal or ceramic resonator) and a PLL tone decoder (like LM567) at the receiver end can be used to confirm the signal.

Want it fancier? Transmit one or a few DTMF tones instead, but that's more circuitry in both ends.