Using the L/MB "latched/momentary" option of the Holtek's HT-12A to select momentary operation of the HT-12D will allow the receiver output pins to be momentarily pulsed low, and then return to logic 1 (5V) once the transmission ends, and you release the HT-12A data input pin from ground. All I want to do is have the transistors switch the emitter to the collector providing ground to the relay coils only when a button is depressed on the transmitter. I do not want the relay coils energized all the time but rather only when a button is pressed.

Here is a link to my project: http://www.electronics-lab.com/projects/misc/007/index.html

 

So this design latches the relay when the button is pressed? Press once for on, again for off?

 

Hello,

The same question came up some weeks ago:
http://forum.allaboutcircuits.com/showthread.php?t=37574

Bertus

 

It would be possible to send a pulse when the button is pressed, and another pulse when the button is released. The downside is if it misses the second pulse you are out of sequence with no way back.

You could also make some logic to make sure only one out of two are on at a time.