SeedHammer controller program

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.

Installation

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

Linux

This command decompresses and writes the image to the block device /dev/sdX:

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

macOS

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

Building from source

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
$ ls result/seedhammer.img

Note that on macOS you will need to set up a Linux builder and start it with nix run .#darwin-builder.

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.

Development

Replacing the controller binary

To replace just the controller program, re-build it with Go and replace the initial RAM filesystem. For example, if boot is mounted on /Volumes/boot:

$ CGO_ENABLED=0 GOARCH=arm GOARM=6 GOOS=linux go build ./cmd/controller
$ echo "controller" | cpio -H newc -o --quiet | gzip > /Volumes/boot/initramfs.cpio.gz

Update through USB

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

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.

Remote control

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, ending with an implicit input b3. Useful for scripting the input of seeds.

Dry-run engraving

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.

License

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

whereswaldon/seedhammer