Hey fellow nerds, I'm new to the world of arduino and just started following some videos and guides to make a pinpad lock for my door, but is there a way to attach a button to the inside so we don't get locked in? I'm assuming that you attach a button through the inputs and somehow link it to the relay, but I literally just got all my beginner supplies days ago. I've read the beginnings of Arduino for Dummies and have everything properly set up, except for the button for behind the door. I have very little experience in electronics and just barely more in coding, as this is my first actual project. Thanks in advanced!
The most foolproof way to hook up your button would be to have it between power and the solenoid for the lock. When you push it, it energizes the solenoid and opens the lock without any code on the part of the arduino. An alternative would be to wire the button to the arduino but then you have have to have code to check the button state and energize the solenoid if pressed.
Either way, if you loose power, you're locked in
A third way would be to connect the switch between 5V and the input pin on the relay module. Again, this will still work if the Arduino crashes, but also it means that only a small current flows through the button, not the full current required to energise the solenoid, which is a good thing if the button is very small.