Okay, I finished my wireless pager system and everything was working great...at first. Now weird stuff it happening. If I turn on the receiver (which consists of the receiver, an HT12D, a 555 timer, and a dc motor) it should do nothing until it receives a signal from the transmitter. Which it does, for a while. However if I let it sit on a table for an hour or so, when I come back it is usually vibrating. How? No transmitter in on to transmit anything. I didn't think it was likely that it would pick up the turn on signal out of noise, but I guess it is possible. Is that what is happening, or did I do something wrong? One thing that I did not do is set any of the Address pins. I didn't set them on the receiver or the transmitter. Could this be part of the problem?
Another problem: If I have the transmitter on and the receiver on and a laser shining into the photo transistor, everything works fine. I can take the laser and shine it into and out of the phototransistor and the receiver will be turned off and on respectively. However, if I leave them both on for about an hour, and come back and try it, it will turn the receiver on when I move the laser away, but not off when I shine the laser back into the phototransistor. This seems very odd to me. The dc vibrating motor cannot be causing any interference in this case, because it is on a 555 timer and turns on and off.
Any ideas? I have enclosed the schematic to both my transmitter and receiver. I realize that the phototransistor is in bacwards on my current transmitter, but I haven't fixed it yet because it still works the way I have it. Or is that the cause?
Thanks!
Another problem: If I have the transmitter on and the receiver on and a laser shining into the photo transistor, everything works fine. I can take the laser and shine it into and out of the phototransistor and the receiver will be turned off and on respectively. However, if I leave them both on for about an hour, and come back and try it, it will turn the receiver on when I move the laser away, but not off when I shine the laser back into the phototransistor. This seems very odd to me. The dc vibrating motor cannot be causing any interference in this case, because it is on a 555 timer and turns on and off.
Any ideas? I have enclosed the schematic to both my transmitter and receiver. I realize that the phototransistor is in bacwards on my current transmitter, but I haven't fixed it yet because it still works the way I have it. Or is that the cause?
Thanks!