And a fun project it is:
Stealth Cell Tower is a Hewlett Packard Laserjet 1320 printer modified to contain and power components required implement a GSM 900 Base Station.
These components comprise:
BladeRF x40 Raspberry Pi 3 2x short GSM omnidirectional antennae with magnetic base 2x SMA cable Cigarette-lighter-to-USB-charger circuit (converting 12-24v to 5v) 1x USB Micro cable (cut and soldered to output of USB charger) 1x USB A cable (cut and soldered to printer mainboard)
Masquerading as a regular cellular service provider, Stealth Cell Tower surreptitiously catches phones and sends them SMSs written to appear they are from someone that knows the recipient. It does this without needing to know any phone numbers.
With each response to these messages, a transcript is printed revealing the captured message sent, alongside the victim?s unique IMSI number and other identifying information. Every now and again the printer also randomly calls phones in the environment and on answering, Stevie Wonder?s 1984 classic hit I Just Called To Say I Love You is heard.