In 2020, I took on the challenge of enhancing the beloved WMF AMBIENT pot with functional features that were missing. Introducing the Smart Herb, a groundbreaking electronic board that upgrades this beautiful garden in miniature.

The original WMF AMBIENT, recently discontinued, integrated a warm white ambient light with three levels of intensity that you could regulate by touching the metallic surface.

The Smart Herbs project introduces a groundbreaking board designed to augment the functionality of the popular WMF pot. With the Smart Herbs board, users can effortlessly monitor the water level, interact through touch, and visualize the water level using a captivating RGB LED ring.

The vibrant addressable RGB LED ring surrounding the pot dynamically adjusts its color to represent the water level, providing a visual depiction of the herb's hydration status.

At the heart of the Smart Herbs board lies an ESP32 microcontroller, providing seamless integration with Wi-Fi and Bluetooth capabilities. This connectivity unlocks endless possibilities, such as remote monitoring of the parameters read by the board (such as air pressure or ambient temperature) and integration with smart home systems.

The board's standout feature is the water level detection mechanism, utilizing a conductive area that accurately measures the amount of water in the pot. This invaluable information ensures having always water in the tank so the plants don't over-stress trying to feed on a dry tank.

Given the nature of this design, long-term durability may be compromised due to the electrolysis of water, which can cause corrosion on the exposed pads. Recognizing this limitation, as it was my initial attempt to achieve precise water volume detection, I mitigated the corrosive impact by measuring conductivity for a duration of less than a second per hour.

However, preserving one of the original pot's standout features was paramount to me: the touch-responsive metallic Cromargan® surface that enables direct user interaction. The ESP32 module effortlessly detects touch inputs, offering the potential to trigger specific actions, such as adjusting lighting conditions (as seen in the original design) or displaying information through the vibrant RGB LED ring encircling the pot. This touch-responsive capability enhances user engagement and expands the possibilities for customization and control.

Users can easily gauge the hydration status of their herbs with a quick glance, thanks to the Smart Herb board's intuitive LED display. The LEDs create a stunning visual spectacle when the water level is at its maximum, gradually decreasing in number as the water level drops, providing a clear and immediate indication of the herb's hydration level.

A highly practical feature of the Smart Herb board is its ability to provide a visual alert when the water tank is completely empty. It achieves this by gently fading a red light on and off, effectively capturing your attention and reminding you to refill the tank.

Thanks to the ESP32's Wi-Fi and Bluetooth capabilities, the Smart Herbs board seamlessly integrates with the Home Assistant setup. Users can conveniently monitor their herb cultivation remotely, ensuring optimal care even when away from home.

The design and installation process wasn't that easy though. Due to the reduced space for the former electronics, I had to design the Smart Herbs board in a way that the PCBs the project consist of, fit properly, sometimes forming even a kind of small puzzle to be soldered with care.

As can be appreciated in the above pictures, the perpendicular union between the boards has a total of 12 exposed pads that are soldered at 90º and that not only serve as a mechanical union, but also transmit the I2C information from the BMP180 sensor (air pressure and temperature), the touch readings from the pad in contact with the metallic pot surface, and even the two pads that (once screwed to the inside PCB) provides...

Read more »