Devlog 002: IT HAS EYES (and other developments)

What’s New:

• Ultrasonic sensor to control the LCD display
• Detailed schematics drawn

The Eyes

I added an HC-SR04 ultrasonic sensor and programmed the Arduino to only wake the LCD when an object is within about 50 cm.
The idea is that the status screen should only come on when someone is actually AT my door, saving power without changing how the project feels to use.
The fun thing about ultrasonic sensors is that they work by sending out sound waves and waiting for them to return. The sound waves are too high frequency for us to hear…but your phone mic picks them up just fine. The result sounds like a tiny helicopter possessed by demons (check the vid).

The boring stuff (schematics)

You’ll notice I’m logging over 5 hours. Take a guess at how many of them were spent drawing these stupid fancy doodles. Go on. I’ll wait.

It was 4 HOURS. I spent 4 HOURS drawing and redrawing circuits. If these circuits don’t work I think I will die.

Anyway…these schematics aren’t for the prototype you’ve already seen. They’re for the next upgrade.
In Devlog 001 I mentioned wanting to control the display remotely from my desk. Well, it’s finally time to make that happen.

In the schematic, I replaced the Arduino Nano in the LCD circuit with an Arduino UNO, which gave me enough spare GPIO pins to wire on CC1101 radio transceiver. I also moved the pushbuttons onto a separate circuit (also attached). This circuit is the transmitter and will sit on my desk.

Next Steps

• Order more parts (voltage regulators, capacitors, etc)
• Finally build the circuit

Hopefully the next update will feature the first successful radio transmission. If not, it’ll feature a lovely video of me punching a wall.

Wish me luck.

Chao

Devlog 001 – The Prototype

(another) dumb idea

Last night, I was visited by the demon of spontaneous irresponsibility. I hopped out of bed at almost 2AM and decided I really wanted to build a doorbell. Don’t ask me why. I don’t know either. I also wanted it to have a screen and display stupid messages.

Issue is, my MP3 player is sitting on my desk, still covered in solder from my last spectacular idea. So my doorbell idea turned into a door mounted light up display.

The idea became to have one pushbutton for when I’m unavailable and one for when I am. When the pushbutton is pressed, it displays a random message on the LCD display for either available or unavailable.

Example Messages included:
“gtfo <3”
“unavailable”
“prolly sleeping”

so I got to work.

the build (prototype)

The actual building part of my example prototype was easy. I used a spare arduino nano, a 16x2 LCD display (from a kit I got 2 years ago, that I never used- sorry grandma), a 5V power supply module, and a couple tiny pushbuttons.

I quickly threw it all together on a breadboard. The wiring was chaos, but it was 2 in the morning so I’m not even sure I noticed.
The only hitch I faced was that I didn’t have the necessary potentiometer for one of the LCD display pins. I ended up using a 2 resistor voltage divider (ty google ily <3).

As soon as the wiring was done, it was time for

coding

i hate it. oh gosh i hate it so much. actually the bane of my existence. It took me an hour to write a simple program. hit me up if you’re willing to live in my closet and write code for me <3.

next steps

For some reason I actually really like the idea of a door mounted DND sign/status updates.

What I’ll probably do next is:

• Add more messages
• Solder it to get it all off of the prototype board
• Design a case for it all
• Add a sensor so the display only turns on when someone is at the door
• Maybe add a remote control system (probably radio) by which I can control the messages from my desk

thanks for reading