Overview:
With the rise of virtual meetings and classes, it can be difficult to communicate with housemates on when a closed door means someone is busy, wants some peace and quiet, or is open to surprise visits.
Doorkeeper was created for users to leave messages for potential visitors on their door. When someone approaches the user’s door, a motion sensor will be triggered, displaying a pre-selected message of “Do not enter,” “Enter quietly,” or “Free to enter.”
Process:
Electronics
I first used a breadboard and jumper wires to test out the different components on a Nano board. This included an LCD module to display the message, a passive infrared (PIR) sensor to sense when someone approaches the Doorkeeper, and a slide potentiometer to select one of the three preset messages to display.
After ensuring that each component worked, I then tested the Doorkeeper with all the components combined and finally soldered them onto a protoboard.
Software
For the final design, the Doorkeeper was programmed through Arduino IDE as follows.
The Nano board continuously checks the slide potentiometer values and changes the message on the LCD display, depending on the position of the slider.
After doing so, the PIR sensor reading will also be checked. If the reading is HIGH, meaning motion is detected, the LCD display’s backlight will be turned on using the setBacklight() function. If the reading is LOW, meaning motion is not detected, then the LCD’s backlight will be turned off.
Hardware
With the Doorkeeper was assembled and tested, I then designed a case and slider cap in SolidWorks and printed them in PLA on a Creality Ender 5.
Finally, I attached the portable power bank that powers the Doorkeeper.
Final Product: