I’m happy to announce the release of Maia SDR, an open-source FPGA-based SDR project focusing on the ADALM Pluto. The first release provides a firmware image for the Pluto with the following functionality:
Web-based interface that can be accessed from a smartphone, PC or other device.
Real-time waterfall display supporting up to 61.44 Msps (limit given by the AD936x RFIC of the Pluto).
IQ recording in SigMF format, at up to 61.44 Msps and with a 400 MiB maximum data size (limit given by the Pluto RAM size). Recordings can be downloaded to a smartphone or other device.
I have a couple of ideas in mind that involve connecting an ADALM-Pluto SDR to a phone or tablet. Usually, the Pluto is connected to a PC through USB, and the Pluto acts as an Ethernet device, so that network communications between the PC and Pluto are possible. I want to have the same thing running with my Android phone, which is an unrooted Xiaomi Mi 11 Lite (model M2101K9AG, if anyone is curious).
As usual when trying to do something slightly advanced with Android, this hasn’t worked on the first go, so I’ve spent some time debugging the problem. Long story short, in the end, the only thing I need to make this work is to run
on the Pluto once and reboot (these settings are saved as uBoot environment variables to persistent storage), then enable Ethernet tethering on the phone every time that I connect the Pluto. I can go to the web browser in the phone and check that I can access the Pluto web server at 192.168.89.1.
Hopefully the rest of this post will give useful information about how everything works behind the scenes, as your mileage may vary with other Android devices (or if you try with an iOS device, of which I know next to nothing).
I haven’t seen many people doing this, so the documentation is scarce. PABR did a set up with LeanTRX, the Pluto and an Android phone, but they were running the Pluto in host mode and the Android phone in device mode, and I’m doing the opposite. Note that when you connect a Pluto and phone together, the roles they take will depend on the USB cable. My phone has USB-C, so I’m using a USB-C plug to type-A receptacle cable (USB-C OTG cable) together with the usual USB type-A plug to USB micro-B plug cable (the cable provided with the Pluto). There is also this thread in the ADI forums, but it doesn’t really say anything about Ethernet over USB.