OPSX-SX70

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OPSX-SX70 is an open-source replacement core board for the Polaroid SX-70 instant camera, built around the Raspberry Pi RP2040. It provides a hackable, repair-friendly electronics platform while preserving the essential camera-control behavior of the original board.

Highlights

• RP2040-based camera control board.
• Factory-ready Gerber files.
• Interactive HTML bill of materials.
• Schematic PDF for circuit inspection.
• MicroPython firmware for rapid iteration.
• Rust firmware workspace reserved for future high-performance control code.

Repository Layout

Path	Contents
bom/	Interactive HTML bill of materials for component lookup and placement.
code/micropython/	Current firmware implementation for the RP2040 board.
code/rust/	Placeholder for future Rust firmware.
gerber/	PCB production files and SMT position CSV.
schematic/	One-page schematic PDF.
docs/	Fabrication, firmware, calibration, and safety notes.

Hardware

OPSX targets a thin two-layer PCB suitable for the physical constraints of the SX-70 body.

Recommended fabrication settings:

• Layers: 2 copper layers
• PCB thickness: 0.8 mm or less
• Assembly: review the interactive BOM before ordering or hand assembly
• Files: use the Gerber package under gerber/

Read docs/fabrication.md before manufacturing.

Firmware

The current firmware is written in MicroPython and lives in code/micropython/.

Core modules:

• main.py: camera-control loop, shutter/motor logic, exposure modes, distance display, and sensor integration.
• ssd1306.py: OLED display driver.
• vl53l1x.py: time-of-flight distance sensor driver.

Read docs/firmware.md before flashing the board.

Calibration and Safety

OPSX controls camera electromechanical parts including a shutter solenoid and motor. Incorrect calibration can damage the camera or board.

Before first use:

1. Read docs/safety.md.
2. Inspect soldering and continuity.
3. Calibrate SOLENOID_THRESHOLD in main.py.
4. Test motor and sensor behavior outside the camera body where possible.
5. Reassemble only after confirming stable control behavior.

Useful References

• Interactive BOM: bom/OPSX_bom.html
• Schematic: schematic/OPSX_schematic.pdf
• Gerbers: gerber/
• KiCad source request: issue #2
• Latest release: https://github.com/sunyitong/OPSX-SX70/releases/latest
• SX-70 repair reference: https://instantphotography.files.wordpress.com/2010/12/polaroid-sx-70-camera-repair-book.pdf

Roadmap

• Document complete assembly photographs.
• Package Gerber/BOM/schematic as GitHub Releases.
• Add firmware upload scripts.
• Add Rust firmware implementation.
• Add calibration logs for different SX-70 bodies.

Author

Created by Yitong Sun, a researcher and developer working across computational design, sensing systems, XR, and open hardware.

• Website: https://www.yitongsun.com
• Email: hi@yitongsun.com

License

This project is released under the GNU General Public License v3.0. Any distribution or modification based on this project should clearly attribute the source.