- New pair of custom band units with minimal optical design with modern components
- Adjusting the LEDs and calibrating the sensors requires a lot of patience in the initial phase of testing.
- Reducing crosstalk has become a key factor in continuously stabilizing signal accuracy.
A retro computer enthusiast has built a new paper tape drive called Putapre, based on a minimal set of modern components.
The unit has only sky the riverwhich required a simple optical system capable of handling perforated tape without the complexity of conventional contact mechanisms.
The design uses an 8-bit PIC18 microcontroller connected via USB and connected to a phototransistor connected to an infrared LED to detect each pinhole in the strip with controlled light passing through the paper.
How the optical system is refined for precision
Skyriver explains that it took a long time to find the right balance between lighting and sensor: the power of the LED had to be adjusted several times to avoid false triggers, while the sensitivity of the phototransistor had to be adjusted to detect precise transitions.
The manufacturer also focused on reducing crosstalk between channels, which required several hardware optimizations.
The choice of ribbon material was important because different papers reacted differently to the passage of light and after several trials the system reached a point where the ribbon could pass cleanly and with consistent measurements.
To stabilize the strip, Skyriver created a 3D-printed guide that keeps the material aligned with the LED and sensor.
The control ensures that the tape does not move during movement and ensures that the optical path remains stable during flow.
With this mechanical support and some practice in manipulating the structure, the player has become predictable enough to prove this.
Skyriver notes that these improvements were essential for reliable hardware performance.
The software responsible for interpreting the signals currently only performs essential actions, but Skyriver wants to improve this next.
Early estimates suggest that the drive spins around fifty bytes per second, meaning users shouldn’t expect high read speeds.
Although this percentage is still higher than older contact systems, it is still modest by modern standards.
Perforated tapes played an important role in the early days of computing before being replaced by magnetic media, and continue to generate great interest among hobbyists.
Skyriver proposes to create a compact cutting device that can produce ribbons without vector files or laser cutters.
However, the results of this project are quite slow and its focus is very limited, suggesting that it will have limited practical value.
However, this reflects an interest in recreating historical technology for experimentation rather than efficiency.