Putting an Exclamation Point on Your Smart Home
This exclamation point-shaped device offloads digital pings to wall art, using an ESP32 and an analog bell to kill notification fatigue.
What are we to do about notifications from our electronic devices? They would be hard to live without — no one would remember to show up for meetings, call friends on their birthdays, or check the oven before the roast turns into charcoal. However, they are also tough to live with. When we are focusing on other tasks, they regularly pop up and interrupt our flow. It would seem that we can’t live with them, and can't live without them.
Conrad Farnsworth has joined the growing trend of 'offloading' notifications — stripping them from his primary devices and moving them onto dedicated hardware. The idea behind this movement is that you can still get the notifications you need, but without being assaulted by them in a way that disrupts productivity. Farnsworth’s solution isn’t necessarily innovative in the way it works, but it does the job with style that most DIY devices lack.
His creation, called the “! Notifier,” looks more like a piece of wall art than a gadget. Mounted in a 3D-printed housing in the shape of an exclamation mark, the device combines bright blue LED panels with a physical bell. When triggered, it flashes icons and rings out across the house, distinguishing events such as mail delivery or a car entering the driveway.
The notifier ties into sensors and home automation software to receive notifications. Powered by an ESP32 microcontroller, the system connects to Wi-Fi and communicates through MQTT, a lightweight messaging protocol commonly used in smart homes. It can receive automated triggers from Home Assistant, ring a solenoid-driven bell in different patterns, and display custom text across three 8×16 LED matrix panels.
Farnsworth modeled the enclosure in SolidWorks, printing multiple interlocking parts and embedding heat-set threaded inserts to hold everything together. Even the LED circuit boards were carefully sanded so they could sit flush behind custom light masks that form the icons. The bell itself is mechanically struck by a small 12-volt solenoid, producing an unmistakably analog notification sound — something no push notification can replicate.
The source code and design files have all been made publicly available for those who would like to make their own ! Notifier. You can grab them from the project write-up.