Table of Contents

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.

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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.

Screenshot

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.

Formula Graph

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.

Format editor

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.

Resources

Firmware
UI
Documentation
Homebrew Talk
Web Flasher

Supported board options

 


Board:
esp8266 mini
esp32c3 mini
esp32s2 mini
esp32s3 mini
esp32c3 zero
esp32c3 supermini

Manufacturer:
lolin
lolin
lolin
lolin
waveshare
tenstar *)

Latest version:
v2.2.1
v2.2.1
v2.2.1
v2.2.1
v2.3.0-beta3

Status:
Supported
Supported
Supported
Supported
Supported
Work in progress

Hardware:
iSpindel
iSpindel
iSpindel
iSpindel
Gravitymon
Gravitymon

Bluetooth:

DS18B20:

Low pass filter:

Gravity velocity

*) There are several manufacturers that produce super mini boards and there is no standard for the pinout of these boards.

Discontinued board options

 


Board:
esp32d1 mini
esp32 lite

Manufacturer:
lolin

Latest version:
v2.2.1
v2.2.1

Status:
Discontinued
Discontinued

Hardware:
iSpindel
Floaty

Bluetooth:

DS18B20:

Low pass filter:

Gravity velocity

Gyro options

 


MPU6050
MPU6500
ICM42670-p

From version:
v1.0
v1.0
v2.2

Calibration:
Required
Required
Factory

Communication:
I2C
I2C
I2C