This project implemented new AREDN functionality on a shelf of Raspberry Pi modules, to provide analog/DMR linking, a replacement for the original PiWxRx, and a third for backup supply monitoring and future uses. A wireless access point was added using a Ubiquiti Air Router node, and newly developed HATS were used for powering the pi modules, and other new boards for power injection and distribution.
The three Pis, from back to front, are used for the following purposes:
- PiWxRx Replacement the original module was a standalone device, it has now been integrated into the shelf and utilizes the pi power HAT for its own power as well as providing power for an external USB hub that houses the SDR dongle.
- Remote Access a project still in definition, the middle pi is equipped with an apache 2 web server, and DHCP server. The intention is to provide access to remote devices which connect to a VLAN, which launches a web page. This page then provides a login for the remote station, which can then join the mesh network. Candidates for remote access are the D-Star mode on 1296 MHz, which provides 128KB/s. A netgear GS105E provides external connections to the pi VLAN.
- Digital Repeater Linking the third hosts the USRP linking software for analog repeater linking, and also an AMBE codec for transcoding analog to DMR formats for linking to digital hot spots.
Two additional home brewed boards were used in the shelf as well. The first is a simple power distribution board providing a 1-to-4 fanout of Anderson power poles, the second is a POE injector to provide +24V to the Ubiquiti node, via a 12/24 boost converter. This ensures that the entire shelf can run from a 12v supply.
The individual pi architectures are described in their own subsections from this page.