Here's a bit of a deep dive.
The things you're trying to control aren't super difficult, but require some background. Software and Hardware (control and interface) are the items you'll need to decide on.
The control hardware is probably the easiest part, you need something that has WiFi, has digital I/Os, and can connect through an interface to a control system. A Node-MCU would suit many needs. It has the capability of having multiple temperature sensors (I use DS18B20), digital inputs/outputs, and a single analog input. This small board has the ability of using interfaces such as MQTT, serial (USB, or using level converters 3.3v vs 5v), I2C, etc. I'd recommend MQTT for just about anything you want "mobile", such as WiFi devices. MQTT requires a "broker", which is a program that can be on PC, Raspberry Pi, Linux machine...
If the equipment you want to control would be easily wired, an Arduino with built-in WiFi (or WiFi daughter board) utilizing BruControl as a control system could be very easy as well. Arduino Mega boards have many more digital I/Os and Analogs at your disposal, if you wanted a system that can do it "all". Definitely look into BruControl, I've read up on it extensively, and it seems like a very robust software, and has great support (
@BrunDog). Definitely many options on the table.
The nuances of different software systems sometimes aren't clear though. BruControl, along with other PLC type interfaces use a PC, and I'd recommend doing the same. When it comes to equipment, safety, and controls; proven hardware is definitely recommended. Don't get me wrong, I've had great success using a Raspberry Pi controlling my system, it also has its shortfalls. To cut a long story short, if the system uses a database (if you're datalogging temperatures, valve states, pH, gravity, DO, etc.), get a PC or an actual HDD attached to the Raspberry Pi for the database backup. SD cards simply aren't meant for that duty.
Here is my system as a use case. My system runs on Node-Red, which is free and can be installed on PC, Raspberry Pi, Linux... It is a very "portable" software interface, in that it can communicate through Serial (USB, RS232), MQTT, I2C, Web Interface, etc. My Node-Red interfaces with an Arduino Mega through MQTT (the Raspberry Pi that has Node-Red installed is also the MQTT Broker). The Arduino handles all of the dirty work (inputs and outputs). It is constantly reading temperatures and sending back readings via MQTT. It is also subscribed to MQTT topics to check for updates of different system states (Hot Liquor Tun and Mash Tun setpoint temperatures), valve states, pump states, etc. Node-Red is the one sending these system states via the incorporated web-interface. I have it set up that I can import a Beersmith file via the web interface and it fetches the data it needs to calculate mash times, mash and sparge temps, HLT and MT fill volumes, etc. All of the variables of the system get pushed into an Influx Database for storage, and I use Grafana to visualize the data. Some day I'll get around to making a post about my automation setup...
As extensive as it seems, it also comes with little support. Node-Red, Influx, and Grafana are open source, but you can find a bunch of information on the nuances online. I believe there is another member on the HBT that recently posted his Node-Red flow that has temperature, PID and a bunch of other controls.
For your case, you'll first want to figure out how the hardware works. Questions need to be asked:
What type of heat? (Electric, Gas, Steam?)
What type of vessels? (Stainless, Igloo?)
What type of pumps? Voltage, Amperage
What type of valves? Motorized Ball (state or proportional), Diaphragm (pneumatic or electric), solenoid?
The interface hardware for different voltages and amperage to a microcontroller need a bit of research for the hardware to be interfaced correctly (relays or transistors). Micro-controllers use a low voltage to outputs signals, so you'll likely need an interface board to transition from a 0-5v (or 0-3.3v) signal to make higher voltages change state. Background in electronics is definitely helpful. BruControl definitely makes its case with interface boards and valves available for purchase.
Narrow down what kind of brewing you'll want to do (all grain, RIMS, HERMS, burners, elements..), then choose how easiest to implement controls into that hardware. If you don't have background, or don't want to learn soldering, maybe BruControl is a suitable option. If you'd like to learn to solder and write code, then maybe open source is appealing.
I hope I didn't scare you away from automating, it can really help take some stress off of the brew day, conversely it can add stress in researching and setup to get going. From there on, its all about perfecting.
If you have any questions, don't hesitate to ask.
Cheers.
