Kto W Domu (KWD)

KWD a small webserver used to work with a Raspberry Pi 0 W to check if the door lock is open.

How it works?

Raspberry Pi 0 W is reads out the input of a limit switch that is placed at the end of a lock socket.

• If the lock is closed (meaning there is noone in the office) the limit switch is pressed and status is set to EMPTY
• If the lock is open (meaning someone is in the office) the limit switch is open and the status is set to OCCUPIED

Setting up the system and the server

• Install Raspbian on the device.
• Install node via Apt (if it is Raspberry PI 0, only node up to 11.X.X supports it's ARMV6l architecture)
• Move the files to raspberry Pi (e.g. through cloning this repo).
• Install all dependencies via NPM (Note: onoff module requires Python2 as main python command, so you may need to change your bash profile as current Raspbian comes with Python3 as default Python).
• Set up tunneling (I've used Dataplicity but there could be other alternatives, just make sure they work with ARMV6l and older node versions).
• Create office_status.txt file in the server catalogue.
• Run the server. You should now be able to access the server via your tunneling wormhole from anywhere.
• From the limit switch connect the NC to GPIO 22, NO to GPIO 27, power up the switch (you can use any GPIO, but those are default)
• Interrupts from witch should now write to your office_status.txt file which will be read by the server and will return the status of the office - Congrats!

What to improve (27/04/2022)

• Add better error handling
• Add reading input from both pins
• Setup a nice domain url
• Add running the server to CRON so that it runs on booting the OS