A macro stacking rail

Firmware

The firmware is written with zephyr. The code is in ./app.

The environment can be bootstrapped via nix run .#init and west is either available via nix run .#west -- ... or in nix develop.

It runs on STM32H7B3I-DK (in Zephyr: stm32h7b3i_dk). Bluetooth is added with the dev board X-NUCLEO-IDB05AI.

State and State Machine

• The rail knows its absolute position and the current target position.
• It knows how many images to take per stack.
• It knows the absolute positions of Start and End of the stack.

It internally has a state machine:

Version of Zephyr

The version of zephyr is pinned via the ./flake.nix and the script ./scripts/init-and-chores.sh updates the app/west.yml from that.

UI

It has a GUI with LVGL.

PWA

connected via https://maxhbr.github.io/zephyr-rail/, which hosts the static HTML part of the PWA.

Hardware

Some of the shelf Mechanical Parts used in this project:

• Rail: HiWin KK5002P
• Stepper Motor: iCL Series NEMA 17 Integrated Closed Loop Stepper Motor
• Arca Swiss Clamp round, diameter 60mm: link to mjkzz
• Camera Plate 200mm: e.g. LEOFOTO Quick Release Plate PL-200

3D Printed

Some adapters and parts are 3D printent. See ./3d-print.scad.

Electronics

Electronics

• Control of the Stepper Motor
• Control of the Camera via Bluetooth
• Frontend via Bluetooth PWA
• 24v -> 5v conversation to power the MCU
• Ideas:
  • IMU to wait for the rail to settle
  • piezo beeper
  • limit switches and positioning

A high level sketch:

Software

For stacking and other things the project https://github.com/maxhbr/myphoto is used.