Keen readers will have spotted that the writer of these pages has recently rediscovered home beer brewing. The core of this project is a modified refrigerator that holds the fermentation vessel. This is where the sugar turns into alcohol and the wort into beer, and the key to its flavorful success is temperature control. The modified fridge is controlled by an Arduino Uno running firmware that reads sensors connected to the fermentation vessel and the refrigerator, and it uses this information to either turn on a small heater or the native cooling function of the refrigerator itself. The result is incredibly precise temperature control of your brewing environment, and consequently, excellent beer. You can read more about this very build in the first issue of Linux Voice.

This Arduino-controlled brewing setup is remote controlled and monitored from a USB-connected Raspberry Pi running a LAMP stack called BrewPi. BrewPi is still in business, and the project now produces excellent commercial hardware and software, but its old code stack is now considered legacy and hasn't been updated for years. This means it has become difficult to install, maintain, and modify. Which is where Fermentrack comes in. Fermentrack is a modern reimagining of that old legacy BrewPi software stack, except it's open to all kinds of different hardware and built atop a modern Django-based web front end. If you've got an old Arduino-based BrewPi, it will just work. But Fermentrack works with a much wider variety of hardware too, including replacing the Arduino with the brilliantly cheap (and wireless) ESP8266. You can also easily add gravity/alcohol measurers, such as the DIY iSpindel and the Bluetooth Tilt, neither of which worked with the original BrewPi without hacking its PHP. And you can even monitor more than one fermentation refrigerator from the single Fermentrack controller.

All of this modernity becomes apparent when you install Fermentrack. It needs nothing more than a freshly installed Raspberry Pi image and even the diminutive Lite version will suffice, as too will any other Linux installation. Everything else is then handled by an installation script that sets up the passwordless user, the various dependencies, and the Django front end. With that done, you simply connect to the Nginx-provided web page, and it walks you through the final configuration. If you've got a standard Arduino or ESP8266 controlled setup, this requires little more than connection info, after which your various sensors and switches become integrated into the front end. In use, Fermentrack offers exactly the same amount of control over your brew as BrewPi. You can switch between having a constant beer temperature, a constant fridge temperature (which is useful for cooling the product, or if you don't have a beer temperature sensor), and a beer profile, which lets you create a spreadsheet of what temperature you require and when. Beer profiles massively help when you need to start fermentation at a lower temperature and raise it throughout the process to keep ester tastes to a minimum. A real-time chart maps changes in sensors and settings over time, and while it lacks the annotations of BrewPi's old UI, it does include gravity readings and feels much more modern and responsive. The end result is a simple, low-cost setup that can transform a spare or broken fridge into something capable of almost commercial quality results. Hic.

Project Website

Track beer temperature, room temperature, and gravity during fermentation, and control its temperature with precision.
Fermentrack will detect a BrewPi sensor and controller configuration and add them automatically.

Tower defense


The first thing you notice about Mindustry is just how polished the game is for an open source title. This is likely because it's commercially available from Steam and various mobile app stores, as well as F-Droid on Android. This is definitely a good thing, because both the income and the accountability of paying customers have helped develop a game with fantastic playability, graphics, multiplayer, and developer support. It's a huge credit to the developers that they've been able to do this while releasing the code as GPL. While you can download or build the game in the usual way, we'd highly recommend picking up the game from one of its commercial channels. The game itself is a brilliant and hugely playable 2D, top-down, tower defense game. The unique selling point is an emphasis and a unique take on resource collection, and it starts with your humble agile craft encroaching on a new randomly generated landscape.

Each landscape is littered with different minerals, and your player zips around zapping these back into your base. What's unique about this is that you can quickly start automating the process by building circuits of conveyor belts to collect and collate for you, allowing you to harvest resources automatically and become more ambitious in the buildings and defenses you deploy. But you need to build quickly too, because your base will soon be attacked by waves of adversaries, all of whom will attempt to breach your titanium walls and gun placements to take over your base and resources. There's even a campaign mode where worlds and their resources are hand-crafted, and a multiplayer mode where you can defeat strangers on the Internet. It's smooth, performant, easy to learn, and accomplished, with fantastic sound and (retro-themed) graphics. But most importantly, it's brilliant fun.

Project Website

If you would rather relax while playing Mindustry, there's a Sandbox mode that provides unlimited resources.

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