The LimeSDR Mini board from Lime Microsystems has been paired with a Raspberry Pi 3 Model B+ host to develop a compact, low cost self-contained weatherproof base station for the Electromagnetic Field (EMF) Camp. EMF Camp is a bi-annual 3 day festival for makers, artists, scientists and engineers. It has grown over the years to be something of a highlight in the calendars of many with an inquisitive mind or an interest in making things. Featuring talks on a diverse range of topics spanning science, technology, craft and much more, the UK event has a packed programme and with over 2,000 people taking part.
Connectivity is taken very seriously and while the festival is hosted in a rural area of outstanding natural beauty, a significant amount of time and effort is invested in making sure that there is reliable high speed internet access, with networking to tents and even a temporary NOC set up.
The solution Lime provided is based around the LimeSDR Mini board paired with a Raspberry Pi 3 Model B+ host, which will run Linux together with a fully open source GSM base station (BTS) stack courtesy of the Osmocom Cellular Network Infrastructure software.
Power is provided via a 24V mains adapter and a DC-DC converter integrated into the weatherproof enclosure providing 5V to the Raspberry Pi. Since these will be mostly mounted outdoors and rain is a common feature of the British weather, IP67 rated DC power, Ethernet and SMA connectors were used to prevent against water ingress.
The enclosure is secured to a laser cut MDF backplate to enable it to be easily mounted on a mast or wall. Following assembly, each BTS was put through testing to ensure correct operation.
