This my homebrew duplex hotspot running on Pi-Star software. The main components are the Raspberry Pi Zero, MMDVM HS Duplex Hat, 2.4″ Nextion Touch Screen display and a 12V to 5V step down voltage converter. Everything is enclosed in a small plastic box found on eBay.

The hotspot can be powered by either a regular 5V micro USB power adapter or any 12V power source. The three pole toggle switches on the front panel are the voltage and fan speed selectors. Everything works really well together but it’s somewhat bulky and can’t really be used for mobile/portable operations. For that I prefer the much smaller simplex hotspot.