Hi! My name is Rex and a newbie electronic enthusiast.
I'm trying to create a presettable 0-99.9 seconds countdown timer that will drive a solenoid when the coundown reaches zero.
Operation:
1. Set the BCD thumbwheel switch according to the desired starting countdown time. (00.1 - 99.9 seconds)
2. Upon pressing of the trigger switch,
the counter IC will be load the value of the above mentioned settings,
disable the input trigger switch,
and starts counting down.
3. Upon reaching zero,
a transistor will drive a solenod;
the load value is reset based on the setting in procedure 1;
and the tigger input is enable again.
4. Should the trigger switch is still pressed,
proceed to procedur 2-3.
Else if not, counter will wait until reigger switch is pressed again.
Main Componenet:
1x 555 timer IC
3x 74193 countdown counter IC (or equivalent)
3x BCD thumwheel switch
1x spst push button switch
I have attach a reference circuit.
Thank you very much in advance for all the help that will be contributed in this project.
Have a nice Day
-Rex-
I'm trying to create a presettable 0-99.9 seconds countdown timer that will drive a solenoid when the coundown reaches zero.
Operation:
1. Set the BCD thumbwheel switch according to the desired starting countdown time. (00.1 - 99.9 seconds)
2. Upon pressing of the trigger switch,
the counter IC will be load the value of the above mentioned settings,
disable the input trigger switch,
and starts counting down.
3. Upon reaching zero,
a transistor will drive a solenod;
the load value is reset based on the setting in procedure 1;
and the tigger input is enable again.
4. Should the trigger switch is still pressed,
proceed to procedur 2-3.
Else if not, counter will wait until reigger switch is pressed again.
Main Componenet:
1x 555 timer IC
3x 74193 countdown counter IC (or equivalent)
3x BCD thumwheel switch
1x spst push button switch
I have attach a reference circuit.
Thank you very much in advance for all the help that will be contributed in this project.
Have a nice Day
-Rex-
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