What is a logic level converter and when would I utilize one with a brewery controller powered by StrangeBrew Elsinore?
Logic level converters convert a digital signal at one voltage, to another. For example, a signal with states 0V and 3.3V can be be converted to a signal with states 0V and 5V with a 3.3V-5V logic level converter.
In a brewery controller powered by StrangeBrew Elsinore, these converters are necessary when utilizing GPIO to control devices that require a voltage signals different from what a beaglebone black or raspberry pi is able to provide. Common instance of this is with (coil based) relays that require 5V control voltages. These relays may in turn be used to control slower switching processes such as pumps and fermentation chambers (note some of these relays that require 5V control voltages can actually be controlled reliably with 3.3V, see this video for details)
Solid state relays, the relays you would use to control heating elements, usually have lower control voltage requirements and can be connected directly to GPIO.