Enthusiast Fabricates 'Putapre' Tape Reader from Scratch

SkyRiver has released a design for a compact perforated tape reader, capable of processing data at 50 bytes per second using a PIC18 microcontroller.

In an era where solid-state storage measures transfer speeds in gigabytes per second, a retro-computing enthusiast known as SkyRiver has engineered a device that operates at a deliberate 50 bytes per second. Dubbed the Putapre, this scratch-built perforated tape reader offers a modern fabrication of the dominant storage medium of the 1960s and 70s.

Mechanical and Optical Design

The project, detailed by Tom’s Hardware, is built around a compact, custom chassis. Unlike vintage industrial units which often relied on mechanical pins or bulky lamps, SkyRiver’s design utilises a modern optical array. The reader employs infrared LEDs paired with phototransistors to detect the presence or absence of punches in the paper tape.

The device is designed to be highly portable, contrasting sharply with the refrigerator-sized peripherals of the mainframe era. It reads standard 8-channel tape, a format that was once the industry standard for loading software and storing data.

Electronic Architecture

The device is controlled by a Microchip PIC18 microcontroller. This 8-bit processor manages the timing and interprets the signals from the optical sensors.

SkyRiver developed the unit to interface with modern systems via USB, allowing it to function as a bridge between legacy media and contemporary hardware. This capability allows archivists to digitise surviving paper tapes, preserving the software and data stored on the fragile medium.

Performance and Context

The Putapre operates at approximately 50 bytes per second. While modest by modern standards, this speed is consistent with the physical limitations of pulling paper tape through an optical reader without tearing it.

SkyRiver has shared details of the build on social media, noting that the project was inspired by a desire to interact physically with computing history. The creator is also exploring the development of a companion punch device, which would allow users to fabricate new tapes from modern digital files.