I have got this circuit working with some of your help and now have a small issue on repeatability.
12v is supplied and the timer module of a mains on off timer is powered with 1.5v. when the timer is set to ON, this then powers up the 555 timer circuit and a receiver board on JP2. pin 4 on JP2 is connected to pin 2 of the 555 timer and starts it. All of this works well.
HOWEVER!!!
when I power on the initial 12v to the 555 sometimes triggers and sets off the sounder circuit. once powered on when I cycle the mains timer module from off, auto and on, when It gets to on, the 555 timer triggers then also. It should only trigger when J2 pin 4 gives it a negative signal.
If I disconnect the timer board...all works well powering on and off so when no load on the 555 timers it all is fine.
Any thoughts.
![Capture.PNG Capture.PNG](https://forum.allaboutcircuits.com/data/attachments/162/162237-f776a4b914d5a95ed61059f5bb72652b.jpg)
12v is supplied and the timer module of a mains on off timer is powered with 1.5v. when the timer is set to ON, this then powers up the 555 timer circuit and a receiver board on JP2. pin 4 on JP2 is connected to pin 2 of the 555 timer and starts it. All of this works well.
HOWEVER!!!
when I power on the initial 12v to the 555 sometimes triggers and sets off the sounder circuit. once powered on when I cycle the mains timer module from off, auto and on, when It gets to on, the 555 timer triggers then also. It should only trigger when J2 pin 4 gives it a negative signal.
If I disconnect the timer board...all works well powering on and off so when no load on the 555 timers it all is fine.
Any thoughts.
![Capture.PNG Capture.PNG](https://forum.allaboutcircuits.com/data/attachments/162/162237-f776a4b914d5a95ed61059f5bb72652b.jpg)