A Pager and Spectrum Analyzer in Your Pocket: Upcycling the SMART Response XE
With some minor modifications and a CC1101 transceiver module, 'ea' shows how an old classroom tool can live a new life as a radio toolkit.
Pseudonymous developer 'ea' has published software and a build guide to turn a SMART Response XE educational handheld into a sub-gigahertz handheld radio toolkit — including examples of running it as a DAPNET pager or spectrum analyzer.
Originally designed as an add-on for SMART Technologies' digital classroom toolkits, the SMART Response XE is a compact handheld device with monochrome screen and keyboard. Teachers would pose questions through SMART's software, and students could answer on the device. Having been superseded by more modern technology, the Response XE units are available cheaply on the second-hand market — and have been repurposed by hackers into everything from handheld games consoles to sniffers for a variety of sub-gigahertz wireless communications.
"I, however, wanted to play with different digital radio modes. You see, this blue case is pretty big, and can easily fit additional stuff inside," ea writes. "[The] CC1101 is a sub-1GHz transceiver IC that can be configured to transmit and receive a number of digital radio protocols. One of these things is about [$]3.50 on eBay, with an antenna!"
After some minor modification to the casing — including drilling a hole for an SMA connector — ea was able to reprogram the microcontroller at the heart of the Response XE and connect a CC1101 module to the SPI bus. All that was left was software, written as an Arduino sketch and with two example projects: A proof-of-concept implementation of a DAPNET-protocol pager, and a spectrum analyzer with live display on the Response XE's screen.
The instructions for converting your own SMART Response XE, as well as the full source code, can be found on ea's GitHub repository.