This repository contains the source code to run the controller program for the SeedHammer engraving machine. It runs on the same hardware as the SeedSigner: Raspberry Pi Zero or Zero W, a WaveShare 1.3 inch 240x240 LCD hat and a Pi Zero compatible camera with a OV5647 sensor.

Write seedhammer-vX.Y.X.img to an SD-card and insert that into the SD-card slot on the Raspberry Pi.

The dd command writes the image to the block device /dev/sdX:

$ dd if=result/seedhammer-vX.Y.Z.img of=/dev/sdX bs=1M

Use a similar command as for Linux or a GUI tool such as balenaEtcher.

To build a complete seedhammer.img image, Nix with flakes enabled is required. The default Nix package in flake.nix builds the image:

$ nix build github:seedhammer/seedhammer
$ ls result/seedhammer.img

The seedhammer.img image contains the Pi Zero firmware, the Linux kernel and drivers, and the controller program that drives the Pi hardware and engraver.

To build a versioned image, use the mkrelease script and specify a tag:

$ nix run github:seedhammer/seedhammer#mkrelease vx.y.z

the resulting image will embed the version. The command also accepts git branches or commits.

The build process is designed to be deterministic; that is, images produced with the above steps should match the released images bit-for-bit. If not, please open an issue.

Use a tool such as shasum or sha256sum to verify that the release binary matches.

There is a crude facility to replace and restart the controller binary on a running device. First, build and prepare a debug build of the image

$ nix build .#image-debug

from a local clone of this repository. Then write result/seedhammer-debug.img to an SD-card. Connect the device to your machine with a USB cable to the USB port closest to the mini-HDMI port of the device; that is, the port usually used to communicate with the engraver.

Then, to upload and run a new version of the controller binary, run

$ export USBDEV=/dev/cu.usbmodem101 # Or (usually) /dev/ttyUSB0 on Linux.
$ nix run .#reload $USBDEV

In debug mode, logging output from the controller is routed through the USB serial device. Use

$ cat $USBDEV

to show the log on your terminal. The nix .#reload command automatically does this after reloading.

There are few commands available to remote control, or script, the device in debug mode.

$ echo "input up" > $USBDEV

sends one or more button events to the device. Available buttons are: up, down, left, right, center, b1, b2, b3.

$ echo "runes ACCIDENT" > $USBDEV

sends text to the device, where every space and the newline sends an implicit input b2. Useful for scripting the input of seeds.

$ echo "screenshot" > $USBDEV

instructs the controller to dump a screenshot to the SD card.

Testing the engraving process without actually spending a plate can be done in dry-run mode. It's activated by long-pressing the middle button on the engraving screen. When dry-run is enabled, a small notice is shown in the lower right corner of the screen.

The files is this repository are in the public domain as described in the LICENSE file, except files in directories with their own LICENSE files.