I want to protect an Arduino from stop running using a 555 timer. I saw some projects that use the Arduino RESET pin to do that but there are cases that my Arduino project still stop working even when I do a reset using the RESET pin.
So I used the circuit below to cut the 5v line of my Arduino. I choose the 5v line instead of the ground because I have only one 5v pin and more than one ground at Arduino.
My problem is how can the Arduino reset the 555 counter? How can I pulse the 555 to prevent it from disable the Arduino? If I connect the D2 Arduino pin to the Threshold/Trigger/Capacitor pin like I saw on some projects, and keep the capacitor charged, it works when the Arduino is running but if it disables it never turn on again because the Arduino don't allow the capacitor to charge again and it stays forever off.
simulate this circuit – Schematic created using CircuitLab