Norbert Heinz Demonstrates "Secure Communication" Concepts with Arduino, Raspberry Pi Pico Terminals
Designed to illustrate his "less is more secure" anti-complexity concepts, Heinz's terminals communicate via infrared.
Self-described "tinkerer" Norbert Heinz has shown off a family of prototypes for text-messaging terminals based on infrared transmission — using an Arduino Uno, a Raspberry Pi Pico, and a custom board built around the Microchip ATmega328P.
"My first 'prototypes' of Secure Communication Terminals are based on a Raspberry Pi Pico and an Arduino Uno," Heinz explains of the project, which is being developed as part of an educational series on physical computing. "Less is more secure!"
Heinz has come up with three implementations of his concept, which communicate messages via line-of-sight infrared using a simple LED and infrared receiver. The first is based on the popular Arduino Uno microcontroller development board, to which an 8x8 LED matrix is added as a scrolling display via a custom-built shield.
Messages are entered into the system via Morse code, using a button connected to the shield. Text so entered is then transmitted to the second unit, built around the Raspberry Pi Pico. This time, messages are displayed on a 320x240 LCD — big enough to display historical messages as well as the latest message received — and text entry is handled by a numeric keypad.
A third terminal builds on the Arduino Uno variant, placing a Microchip ATmega328P microcontroller with Arduino-compatible bootloader onto a custom circuit board alongside another LED matrix and an on-board button for text entry.
"Well, I must admit that this design won't become a million seller either," Heinz writes. "However I will continue trying to improve the look of the terminal."
The three terminals serve as a demonstration platform for Heinz's key point: "Simple," he notes, "is simply more tamper-proof! My guiding principles for secure communication terminals are: Do little when it comes to software, but do it well; Use low-performance hardware, because it will relentlessly reveal if you violate point one; The hardware components should be exchangeable, GPIOs [General-Purpose Input/Outputs] are the only interfaces — internal or to the world outside; Programmable using freely open source software."
Source code and wiring diagrams for the terminals are available on Heinz's website.