GFConnect

GF Connect Bluetooth Controller Proof of concept

Background

The Grainfather Connect controller uses Bluetooth Low Energy (BLE) technology for operation. Specifically, BLE GATT functionality is embedded on the controller to principally allow the Official Grainfather mobile application to control the boiler operation.

Tech Highlights:

• BLE Service Broadcast name: Grain

• Main BLE GATT Service UUID: 0000cdd0-0000-1000-8000-00805f9b34fb

• Write Characteristic UUID: 0003cdd2-0000-1000-8000-00805f9b0131

• Notification (client read) UUID: 0003CDD1-0000-1000-8000-00805F9B0131

• All commands are single line write requests and each request needs to contain 19 characters - padded out with spaces

This proof of concept Python script allows for third party operation of the controller, bypassing the requirement to use the official Grainfather application. This therefore opens up the Connect controller to other brewing applications and custom automation.

Command list so far:

• Timer set: Sx where x = mins to set - example: S1 for 1 minute timer, S5 for five minute timer.

• Cancel: C0

• Pause or resume: G

• Cancel timer: C

• Temp up: U

• Temp down: D

• Heat on/off toggle: H

• Pump on/off toggle: P

• Temperature set point: $X, where X = temp value. Note the trailing comma - example: to set target temp to 70C, $70,

• Delayed heating: Bx,y, where x = minutes, y = seconds. use C0 to cancel this function. Example: B2,0,

• Set button press: T

• Quit session: Q1

• Skip to step: Nx,0,0,0,0,1, - where x step number, e.g., mash1=1, mash2=2, mash out=3, sparge=4, boil=5, hopstand=6

Outline Brew Schedule mode (Work in progress):

• Line 1 - Rboiltime,Number_of_Mash_steps, Mash_water_(L),Sparge_water_(L),

• Line 2 - water_attitions_included,sparge_indicator,sparge_heater_reminder,0,0,

• Line 3 - brew_session_name - capical letters, 19 chars max

• Line 4 - hop_stand_mins,number_of_boil_additions,boil_power_control,0 (TBC)

• Line 5 - boil_addition1_time_mins,

• Line 6 - boil_additionx_time_mins, (where needed - each hop addition adds a line and increments the number_of_boil_additions number)

• Line w - mast_temp,mash_time, (will be the last line if only 1 mash step)

• Line x - mash_out_temp,mash_out_time (if mash out needed)

********************* Work-in-progress code - Use at your own risk! *********************

Prerequisites

Raspberry Pi (v2 with bluetooth dongle, V3) or Linux host

Libs/packages: Bluez, bluepy, Python

Installation/Set Up

TBD

Work To be done

• WIFI control bridge

• More commands?

• Full Recipe mode

• Python refactor - maybe with threading so this is 'callable/triggerable'

• RPI image

• Node.js script

• Node-red workflow

• Brewfather/Beersmith etc. Brewing application integration

Authors

• Simon Taylor - Initial Concept/POC script - BladeRunner68

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE.md file for details