I would like to use a 556 or two 555s in order to simulate the pressing of a pushbutton on a radio. I powerup several scanners via the 12 supply, and when powered, they require an additional keypress after a few seconds to get them to start scanning. My thought is to powerup my circuit with the same power supply as the radios, (or even feed it from the radio) then use the first 555 to delay about 5 seconds, then it would initiate the second 555 to simulate a .25 second keystroke by wiring the output of the second 555 to the wires on the scan button.
My question - How do I trigger the first 555? I would like it to "self-trigger" by powering up the whole circuit. I could just ground the trigger terminal, but that would cause indefinite triggering, and from what I read, the trigger time has to be less than the delay time.
Other uses - This circuit could be adapted to get any equipment to powerup in a mode other than the manufacture designed.
Any help or circuits would be appreciated. Thanks, Oldchap
My question - How do I trigger the first 555? I would like it to "self-trigger" by powering up the whole circuit. I could just ground the trigger terminal, but that would cause indefinite triggering, and from what I read, the trigger time has to be less than the delay time.
Other uses - This circuit could be adapted to get any equipment to powerup in a mode other than the manufacture designed.
Any help or circuits would be appreciated. Thanks, Oldchap