Yet Another Filament Joiner

The heart of this filament joiner is an aluminum heater block with a traditional extruder heater element and thermistor mounted. It works similar to an extruder and as such it is connected to the 3D printer. In that way you can use the printer interface to regulate temperature. On my printer I mounted a quadruple switch between the two thermistor cables and the two heater cables to select between the joiner and the extruder. An additional LED, parallel to the heater, indicates whether or not it