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Overview

This GitHub repository contains the design and specifications for a new touch screen controller, designed to operate an 240V electric Brew in a Bag (BIAB) system. I specifically designed this controller for use with a customized Spike Solo Brew System, but this this controller can be used with any compatible 240v Electric Brew Kettle. Additional documentation can be found at Solo Controller Github Pages site.

Note: This project is not in any way affiliated with Spike Homebrewing.**

Design Concept

The Solo controller is divided into two separate enclosures. The Display enclosure has a touch screen display that controllers the brew system functions. The Display enclosure is envisioned as a light weight box that can be mounted on a swivel arm. This makes it possible for the brewer to move the touch screen display into a convenient location. The sensor breakout box is mount on (or near) the brew rig. This puts most of the cables closer to the brew equipment, keeping the number of cables hanging off the Display enclosure to a minimum.

Key Design Features

Why design a new controller?*** After all, there are a number of BIAB controllers already out there, ready to to purchased and used right out of the box. None of these controllers had all of the features that I wanted for my brew system. So, I decided to build my own. Some of the key design features that differentiate this controller from others include:

Two Temperature Probes: The controller has built in support for two RTD temperature probes. One probe measures Kettle temperature. The other temperature probe can be installed on the output of your wort chiller.
Kettle Volume Measurement: The controller is designed to work with a tri-clamp mounted pressure sensor installed onto the kettle. The controller uses the pressure values measured by this sensor to estimate the amount of wort in the kettle.
Stuck Mash Alarm: This design takes advantage of a unique feature of the Spike Solo system. Should a stuck mash occur, the wort volume level in the main kettle will fall, as more and more wort is pumped into the stainless steal Spike sparge basket. When the wort level in the main kettle falls below a user defined value, an alarm sounds.
Proportional Temperature Control in the Kettle: Most controllers use a standard SSR relay to control the heating element within the kettle. These relays alternate between fully turning on (or off) the heating element. This design uses a proportional SSR relay to control the kettle heating element. Proportional relays allow the controller to apply just enough power to maintain kettle temperature. In my particular case, I was interested in experimenting with longer temperature controlled hop stands. The proportional relay makes it possible to control kettle temperature while minimizing the risk of hops isomerization.
Physical Element Disable Switch: Most touch screen controllers rely solely upon signals from it's microcontroller to enable or disable the heating element. I prefer a physical switch, that will electrically disable the element when needed. This guarantees that a microcontroller or software glitch won't prevent you from disabling the element.
Loud Ass Alarm: Most controllers have fairly weak alarms. This design uses a 12v DC alarm from Auber Instruments to generate 85 decibels. There is no chance of missing this bad boy!

Additional Information

Additional information on the Solo Controller Design can be found here:

Hardware Architecture: Top-level view of the hardware design
- Electronics Design: Design of the control electronics
- Controller Interface Board: Custom Control Board used by the control electronics
- Hardware Parts List: Parts list to build the Solo Controller
Software Architecture: Diagrams describing the structure and functionality of the Solo Controller software

Building a Solo Controller requires an understanding of:

High voltage electrical circuits
Construction of Printed Circuit Boards (PCBs)
Understanding of Mega 2560 microcontroller
Knowledge of C/C++

If this doesn't scare you away then hop on over to the Getting Started guide for more information

Use of this Design

All of the design specifications provided within this repository are freely available for others to use. Please keep in mind, though, that I make no warranties regarding the quality of the electrical design nor the quality of the software provided here. I'm always willing a answer questions, but for the most part, you're on your own should you attempt to build one yourself