NotificationEgg

This repository contains all files needed to build a notification egg.

Video of the egg in action (egg-tion?)

Link to original reddit post

BOM

Picture	Role	Component	Comment
	Microcontroller	ESP32	ESP8266 is sufficient for displays with smaller resolution/color space due to their RAM requirements. I used a WeMos D1 Mini ESP32 for its compact form.
	Display	GC9A01	I love the look of this round 240x240 screen, but it requires a lot of RAM to drive. In an earlier version, I used a SSD1306 0.96" OLED (STL included)
	LED Strip	SK6812 (144LED/m)	More LEDs make for a smoother effect. If you want to go with a non-addressable LED strip, maybe my horrible ESPHome effect can serve as a starting point for you

Miscellaneous/optional components

• MicroUSB Breakout Module: Helps so I don't have to position the ESP near the hole for the wire, also provides some sort of strain relief. Hotglued to the bottom of the inside.
• 80mm x 2mm Aluminium Tube: Cut to 18mm length and added a slot for the wires of the LED strip. Serves as unnecessary heatsink for the LEDs, but the adhesive sticks better to it than to the printed ring...
• 2 M5 threaded heat inserts: Can be inserted into the top to attach the halves together with some ~30mm+ M5 bolts. In hindsight not necessary, my friction fit of the aluminium tube is strong enough so it doesn't come apart easily.
• Perfboard & Connectors: For connecting ESP and the rest. I don't like to solder stuff directly to my MCUs, mostly for misplaced reusability. I used JST XH connectors. I hate crimping...
• Transistor & Resistor: I used a BC337-40 NPN transistor connected via a 1k resistor to the ESP as an electrical switch between the MCU's and the display's GND so the MCU can completely turn off the display. However, I didn't expand on this feature (yet?)

Wiring

Wiring is mostly self-explanatory. All pins of the components are connected to the ESP according to the ESPHome YAML configuration. Change at your own will. Since I was using a MicroUSB breakout board, I connected the 5V of the LED strip directly to it instead of through the ESP board.

Software

The device is controlled via MQTT. It subscribes to a topic esphome/notification-light/{id_code}/notify/{COLOR} for each COLOR in red,green,blue,cyan,yellow and magenta (where {id_code} is set at the top of the config). When a timestamp (in: seconds since 01.01.1970) is published to that topic, the device interprets this timestamp as an "expiration date" for the notification of that color. If a timestamp arrives which has an earlier expiration date than a previous notification of this color, it is ignored. When a timestamp of 0 is received, the notification gets cancelled immediately, no matter its original expiration date.

Update: The config has been adapted to also subscribe to esphome/notification-light/*/notify/{COLOR} to allow easy controlling of multiple devices at once. (Yes, it is weird that # is an MQTT wildcard but * is not. Also, it would be really handy to have the topic exposed in the ESPHome lambdas.)

Firmware

The firmware for the ESP is built and uploaded by ESPHome using esphome run notification_light.yaml. If you don't know about ESPHome, make sure to check it out, it is a simple and awesome way to create firmware for ESP based devices that provides many handy features, like automatic MQTT exposure for your components as well as seamless integration with Home Assistant via their native API or MQTT discovery.

Currently, there are 2 versions: notification_light.yaml, which only controls an LED strip and notification_light_with_display.yaml, which adds support for the GC9A01 display. In any case, make sure to change the GPIO pins in the substitutions section on top of the file, as well as platform and board in the esphome section, depending on your setup.

The topmost substitution is called id_code, which I use to identify different devices. I commented it out, mostly so I don't accidentaly compile a firmware with a duplicate ID. I prefer to set the ID through command line substitutions by running esphome -s id_code 5c9e run notification_light. (My IDs are 4 digit hex numbers, but it can really be anything, as long as it doesn't contain MQTT characters that mess things up, like /, +, # and possibly more).

Config sections

A brief overview over sections of the config that might require some context to understand.

• external_components: ESPHome didn't have support for the round GC9A01 display I used, so I ported the Adafruit Arduino library and submitted it as my first PR to any open source project. ESPHome can just include it via the reference to this PR, which is pretty cool.
• text_sensor: The device exposes a text sensor which contains a JSON of the form color_name: expiration_timestamp. Update: I commented this sensor out because it sometimes caused crashes. I mostly used it for debugging in early development anyways.
• interval: At regular intervals (specified by the refresh_interval substitution), this checks and deletes any expired notifications, updates the text_sensor JSON and scrolls to the next relevant page on the screen, if there is one.
• script: This is where some magic happens
  • clean_overdue_notifications: Checks for each notification class if it should be still active. If not, changes the saved timestamp to 0. (Update: Moved to fragments/script_clean_overdue.config.yaml)
  • scroll_next_page: Changes the displayed page on the screen to the next relevant one. If no notification is active, go to page_default, which shows the current time. Else, cycle between the active notification pages and update the display component.
• mqtt.on_message: Creates the subscription for each color. The included file requires the name of the color (for the topic) and the index of that color in the global arrays.
• button: For each color, a button is created. This button just publishes to the corresponding topic. The timestamp which is published depends on the debug_duration parameter, since its value is added to the current timestamp. I used the buttons for debugging during development, but if you don't want to clutter up your Home Assistant you can just delete the whole section.
• image: Defines the images which are shown on the display. I chose to convert them to TRANSPARENT_BINARY so I could later display them in the corresponding color.
• display.pages: The default page displays the current time, after that the pages for each notification are created. The import requires the index of the color, as well as the id of the image to display.
• switch: I added a transistor between the display's and the ESP's GND, which is controlled by a GPIO pin and can be used to turn off the display. I don't currently use this feature, but by exposing it as a switch I can now create a "night mode" just through Home Assistant.
• light: Controls the LED strip. (Update: Moved to fragments/light.config.yaml)
• light.effects.addressable_lambda: This is the custom effect for the traveling dots. For every active notification, it's dot is "appended". I tried to add many comments, mostly for my own sanity during development, as it took a while to wrap my head around the way one has to write custom effects in this manner. In each step, every pixel is shifted once to the "right", and the rest of the code has the noble task of figuring out what color the first pixel should have. The speed of the effect is controlled by the substition light_effect_interval, but there are several other parameters in the code itself that change things like the width of each colored spot.

Adapting the configuration

If you want to add or change colors, feel free. I attempted to build a custom component in ESPHome that would just be configured as follows:

notification_light:
  blink_every: 10s
  colors:
    - red
    - green
    ...

but decided to postpone that, as it was a little more complicated than I hoped.

Instead, I utilized the brand-new includes with vars (thanks to @jesserockz for pointing me there). The fragments folder contains snippets for the debug buttons, the display pages and the MQTT subscription triggers. You can duplicate and adapt the entries in the button, display.pages and mqtt.on_message sections.

I attempted to move everything else that has to be modified to the substitutions section at the top of the file.

• num_colors is the number of colors. I actually didn't use this in my lambdas, but it is required to initialize the global arrays
• color_values contains an array of the RGBW colors in order of the notifications
• color_names contains their names (only used for exposing the currently active notifications via a text_sensor component)
• empty_array is used to initialize the global arrays for the timestamps at which notifications where received and when they expire. This has to contain as many 0s as the other 2 arrays.

STL Files

As the printed parts are only decorative, perimeters, infill and layer height can be varied to one's own liking.

I printed the top and bottom halves with the "cut" side facing down on the print bed. I added supports in the center, but I'm not sure if that was necessary, however my Voron V0.1 prints fast enough and with bad enough overhangs that I didn't put to much thought into it.

Top

I uploaded a version for a GC9A01 1.28" 240x240 round display (with holes like in this picture) and a SSD1306 0.96" OLED. Both are mounted either with small self-tapping plastic screws or just copious amounts of hotglue.

M5 threaded inserts can be added to clamp the halves together.

Diffusor

I printed this part in spiral vase mode (to prevent a seam) from white PLA. You might want to experiment with your extrusion width settings to get a good fit. The bottom of the part can be hard to fit into the slot, in which case I would just scale the height a little higher and cut the first "layer" off.

I experienced that printing this part in its original size was sometimes tricky to get to fit into the groove without distorting the circle, which I solved by printing it again after scaling it down to ~99.5% in X and Y directions. Fortunately it only takes a few minutes to print and consumes almost no filament, so there is room for experimentation

LED ring

You can substitute this part for a 80mm aluminium tube with up to 2mm wall strength, cut to 18mm length. I thought this would serve as a heatsink for the LEDs, but they are off most of the time so the only benefit of the aluminium is that the adhesive of the LED strip sticks a little better.