This board is based on TI's launchpad, plus or minus a couple of details. 

  • The board is much smaller and uses a small-pitch connector to break out most available IOs.
  • Power/GND on the connector is symmetrical, so the board can be mounted in either direction
  • I use Johansson baluns instead of discrete components for the frontend
  • There's room for external flash, but haven't had a use for it just yet

The biggest changes are on the software side where, instead of fixed types of messages (as in the TI code), messages are made custom, and can be of varying lengths. Another key difference is that each device can change its reporting interval, as opposed to having a fixed one for all. This makes writing firmware for each of the boards much easier, with no modifications required on the Collector side. I have tested line of sight range up to 600 m (2000 ft) with PER of 0, but ran out of space. Another useful feature of these is the ability to update the firmware over the air.

I've used these boards for 

  • a "phosphor" clock
  • ...

At a high level, this project has been:

Antenna Match
Antenna matched for Bluetooth (BW ~110 MHz)
  • Using a SDR (Adalm-Pluto) to dermine frequency offset
Custom board spectrum
Reading frequency offset from 915 MHz
  • Writing firmware (SimpleLink framework + TIRTOS
  • Modifying TI Collector software for custom messaging (basic diff here)
  • Writing React frontend to manage wireless devices
  • Setting up Grafana stack for logging
  • ...and playing with AutoDesk Fusion 360 for 3D prints