Let’s start with the name, MMDVM (Multi-Mode Digital Voice Modem) with HAT(Hardware Attached on Top)
The HAT has been designed by Flo DF2ET and Mathis DB9MAT and is compatible with the Raspberry PI or PI W Zero. The board will support MMDVM so that’s DSTAR, DMR, P25 and Fusion using the excellent software by Jonathan G4KLX.
The Raspberry Pi zero W (WiFi)
The board that brings together the UHF module, the STM32F103 CPU that is plugged directly onto the smallest Raspberry Pi, the Pi Zero W. The hotspot can be configured on the dashboard to operate on any or all digital modes and to operate on the UHF frequency of your choice.
I have mine setup on to provide a digital access point on 435 MHz, but your allocated frequency will vary by local usage and regulations. It has around 10mW of power, so ample to provide access all around the house using a handy.
A close look at the MMDVM_HS Pi Hat
The screen can be anything of your choice, I opted for a small OLED screen but in hindsight, it should have been a little bigger as one’s eyes get older!
Blue OLED Screen
The project and parts are detailed on Github
Who is behind PI-Star
Here you can see both the DMR and DSTAR radio screen.