Include water tank display from Garantia

ESPhomy · October 27, 2024, 9:21am

Hallo Forum-Gemeinde,
ich habe eine Garantia-Füllstandsanzeige in meinem Haus verbaut. Die gibt den Füllstand der Zisterne in % an. link

Den angezeigten Zahlenwert möchte ich in Home Assistant bspw. über ESPHome einbinden. Hat das schon mal jemand von euch gemacht? Es gibt ja schon tutorials, wie man über eine ESP32 -Cam solche Siebensegmentanzeigen digitalisiert, mir wäre es ehrlich gesagt am liebsten den Wert ohne viel Schnickschnack abzugreifen.

vielen Dank schon mal,

petro · October 27, 2024, 10:13am

Please post in English.

ESPhomy · November 3, 2024, 4:57pm

Hey, sorry, i didn’t see, your last massage. Here it is in english:

i have a water tank in my garden with a sensor and display from garantia .

Does anyone has experience with this device and to include the %-value of the display into home assistant? In a little research i read about some project where displays like that could be read by a ESP32 - CAM. But i would rather keep it simple if possible. Maybe the the displayed value correlates with some electric voltage, that could be used?

Thanks in advance for any ideas.
kind regards,
Matthias

ESPhomy · November 4, 2024, 4:14pm

Here is an image of the PCB. Two wires are for the 24 V power supply and two go to the sensor in the water tank.
My assumption is, that the water level in the tank. is direct proportional to the current in that wire. Could i destroy something, when i measure the current in that wire?

Processing: garantia.jpg…

AdrianEddy · November 19, 2024, 6:57pm

Hi Matt, I just did something similar, check it out:

github.com

AdrianEddy/esphome-garantia-water-level/blob/43a4007f1b920a31aaa0c64349c22e1fcc77c4fa/HOW.md

## Background

I have a rainwater tank from Garantia buried in my backyard. It has a controller module like this

![garantia](media/garantia.jpg)

and that module shows the water level percentage on a 3-digit 7-segment display.
That module is in my garage and the only way to check the water level is to actually go there and read it from the display. All my lawn sprinklers are automated in Home Assistant, but it often happens that there is a longer period without rain and the level is approaching 0%. Ideally I want to have the water level value in Home Assistant and include it in the automation to decide how much water do I want to use and also see the statistics over time.

## Problems
- Current hardware has to stay as is, ie. I can't replace the sensor to a smart one. The water tank and all wires/connections were buried a long time ago and I can't run a new cable from my garage to the water tank (they are currently running under the driveway).
- I don't want to use any battery/wireless based hardware as that's a maintenance burden and additional point of failure


## Possible solutions
- Set up a small camera (eg. ESP32-cam) pointing to the module's LCD and display the image in the dashboard. Doable but the value can't be used in automations. I could add an additional OCR, but that's way too fragile
- Plug myself between the sensor and the module. That is not ideal because it can introduce inconsistencies between values read by the module and my new hardware, because of the sensor calibration (which is stored in the module). Also, that sensor is not easy to interface with since it uses 12V modulated signal
- Plug myself to the LCD display connections. It's the simplest solution (since it's either 5V meaning segment is on and 0 if it's off). Easy, but not great because I have to wire 24 pins of the LCD to the ESP32, which will take quite a bit of space. Maybe we can do better?

## Let's open the module

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