Gravitymon
Gravitymon is an open source brewing software that allows you to build your own electronic hydrometer. With it you can keep an eye on your fermentation progress without wasting a lot of beer on samples. Just integrate it with your favourite brewing software. And its free!!
Works on hardware based on the iSpindel or the Floaty hydrometer.
Flash a device through the web flasher
Service integration
A number of popular brewing software are supported and validated, Most of these will work with limited setup.
Examples include; Brewfather, BrewSpy, Brewers Friend, Fermentrack, Ubidots, Thingsspeak and Home Assistant.

Modern User Interface
The user interface is build on modern standards such as HTML5 and REST API's. Its easy accessible over WIFI when the device when placed in configuration mode. There are lots of configuration options available.

Advanced gravity formula creator
You don't need any excel sheets or other tools to create the calibration formula for the device. Just enter your measurements and let the device calculate and validate the formula. You can view the alternative formulas and choose the one that you like best. The result is displayed as a graph that allows you to visually check if it looks good enough.

Customize data sent
There is a built editor to allow you to customize the data format that is sent to external services. This makes it possible to support any external service without the need for software changes. HTTP, HTTPS, MQTT, InfluxDB is built into the software.
Features
Hardware options
Support multiple boards and gyros!
Gravity velocity ESP32
Show the number of estimated gravity points per 24h 2.2+
Low pass filter ESP32
Run the gravity data through a low-pass filter for more stable readings 2.2+
Advanced formula editor
Create your gravity formula on the device, see a graphical representation of the result and select the option that works for you
Easy configuration
You can easily access the web based configuration by placing the device on a flat surface or plugging in the charger
Multiple endpoints
The device has the possibility to send data to 5 different endpoints at the same time
Gyro temperature
The gyro actually has a built in temperature sensor which can be used instead of the DS18B20
Stability detection
Movement will be detected when reading the gyro and data will not be sent until data is stable again
Temperature correction
Automatically adjust gravity values based on the beer temperature
Temperature Sensor
High precision temperature measurement using an DS18B20 sensor
Web Protocols
Support web standards for sending data; HTTP (Post/Get), MQTT and Influx DB v2
Open Source
Fully open source, free to use and modify in aligment with the MIT licence
RESP API
Standard REST API for scripted interaction with the device
Updates
Software can be updated over the air (OTA)
Internationalization
Temperatures can be shown in either Celsius or Fahrenheit and gravity in SG or Plato
Configuration
Lots of configuration options to tune the operations of the device
Backup & Restore
Save your configuration and restore if needed
Low battery detection
Enter battery savings mode (increase sleep interval) when low battery is detected
Wifi Direct
Wifi Direct in combination with Gravitymon Gateway
WiFi Scan
Scan and connect to the strongest WiFi Access Point (AP)
Bluetooth ESP32
Multiple bluetooth transmission options, Tilt, Gravmon, RAPT
Migration from iSpindel
Simple upgrade from an calibrated iSpindel setup, formula and gyro calibration settings migrated
Format Editor
Easy customization of data sent via editor
Hardware test
Built in hardware testing features
Hardware design
Here you can find the hardware (pcb) design used to build a device. This is the first variant based on the Waveshare ESP32 c3 Zero. More details can be found in the documentation including how to order and the full bill of material.
Supported board options
*) There are several manufacturers that produce super mini boards and there is no standard for the pinout of these boards.
Discontinued board options
Gyro options