- Wed Mar 04, 2015 8:50 am
#180214
My question is:
Is this circuit safe for the Arduino?
Background:
This is my first real Arduino and 555 timer project. I don't want to blow up my Arduino. The 555 will be in bi-stable mode. The idea is to use an LDR to turn on the output of the 555, which turns on a transistor which powers up the Arduino. When the Arduino gets its job done it will set a pin low to turn off the output of the 555, shutting down the Arduino. I want to power the system with a trusty 9v battery, so I am concerned about the voltage at the pin on the Arduino that will turn off the 555 output.
The relevant part of the circuit is here:
555-Pin4
|
9v--10k-+-10K--GND
|
Arduino Pin12
Between the 2 resistors there should be 4.5v and a max of .9mA, discounting the 555, which is what I am concerned about. Will grounding pin 4 of the 555 through the Arduino draw additional current from the 555 and damage it?
Is this circuit safe for the Arduino?
Background:
This is my first real Arduino and 555 timer project. I don't want to blow up my Arduino. The 555 will be in bi-stable mode. The idea is to use an LDR to turn on the output of the 555, which turns on a transistor which powers up the Arduino. When the Arduino gets its job done it will set a pin low to turn off the output of the 555, shutting down the Arduino. I want to power the system with a trusty 9v battery, so I am concerned about the voltage at the pin on the Arduino that will turn off the 555 output.
The relevant part of the circuit is here:
555-Pin4
|
9v--10k-+-10K--GND
|
Arduino Pin12
Between the 2 resistors there should be 4.5v and a max of .9mA, discounting the 555, which is what I am concerned about. Will grounding pin 4 of the 555 through the Arduino draw additional current from the 555 and damage it?