Budget Beer Level Monitor
This ESP32-based monitoring system weighs five kegs to calculate liquid level, keeps parts costs low.
According to RickLloyd24’s beer monitor project write-up, you can track the amount of beer left in a keg via flow measurement or by the weight of the keg. Flow measurement systems tend to be cheaper at around $500 for six taps, while weight setup are more expensive at around $1,000 for five taps.
Flow measurement systems are arguably inferior, as they need to be cleaned regularly. One could also see the level being thrown off if a pour was missed for whatever reason.
RickLloyd24’s system measures beer levels on five taps for around $100, using the superior keg weight methodology. It can calculate the amount of liquid in ounces, and as in terms of 12-ounce glasses.
The system runs on an ESP32 breakout board, which takes input from five strain gauges via HX711 load cell amplifiers, giving the current keg weight and thus beer volume. This information is output on a VGA monitor, controlled directly by the ESP32’s pins and a breakout module.
User input is via a PS/2 keyboard, which also interfaces with the ESP32’s pins, and a resistor setup is used to compensate for the keyboard’s 5V operation (versus the ESP32’s 3.3V requirement). Using a VGA monitor cuts down on the price of the project, as they are readily available inexpensively or free on the used market. However, the PS/2 keyboard can be a bit harder to find.
The system can take input from one or more temperature sensors as well, allowing it to cycle power to a beer keg-modified freezer, AKA "keezer," via a relay. This keeps beer cold, but not frozen.
It uses a second ESP32 breakout for Wi-Fi transmission, enabling email and text message notifications. Port forwarding is even implemented for worldwide beer monitoring! Further code and hardware information is available on GitHub.