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View a video tour of the word clock at YouTube.
Read all about the project on the wiki.
Bill of MaterialsSee the README file in each directory for more information.
| Directory | Description |
|---|---|
| carbide3d | Carbide Create designs for various clock components. |
| code | The code that needs to be copied to the Pi. |
| docs | The manual and other printed material. |
| face | Adobe Illustrator face designs for the clocks I've built. |
| pcbs | KiCad printed circuit board designs. |
| File | Description |
|---|---|
| aws-s3-policy-example.json | An example AWS IAM policy file for granting the word clock S3 permissions. |
| manual.docx | The user manual. |
| pi-pinouts.md | What passes for a schematic. |
The clock program, wc, runs as a systemd service. It must run as root to be able to
access the I2C hardware. The program uses the Python asyncio framework
for orchestrating real-time processes. You can also run the program from the command line,
with options to display verbose debugging messages.
Each clock's magnetometer must be calibrated. The result of the calibration is stored
as a JSON file, /var/wordclock/compass.json. The word clock program reads the file
on startup. To perform a calibration, start the calibrate program and then slowly
rotate the magnetometer through all possible orientations.
The clock can be configured to phone home periodically, to upload systemd logs for the clock service, and to download and install new software. The clock phones home simply by reading and writing an AWS S3 bucket.
The clock uploads a log file daily, and saves it as logs/<username>/log-<timestamp>.txt,
where <username> is the IAM user name you'll create, as described below.
The clock checks for updates hourly. See the documentation in wordclock/get_update.py
for more information.
Here's what you'll need to do to make the phone-home feature work:
aws-s3-policy-example.json is an example IAM policy.[default] section of file /root/.aws/credentials.The Python package includes several test programs:
| Program | Description |
|---|---|
| tneo | Send test patterns to the neopixels. |
| tsense | Test and report values for the sensors: magnetometer, accelerometer, and light sensor. |
| calibrate | Calibrate the magnetometer. |
Notes to myself:
Add my own ssh public key to /home/pi/.ssh/authorized_keys.
Allow ssh agent forwarding when root by creating a sudoers file. This will allow me to use ssh to access github.
visudo -f /etc/sudoers.d/ssh_agent_forwarding
In VI add this line and save the file:
Defaults env_keep += "SSH_AUTH_SOCK"
Add this line to /root/.ssh.config so that I can ssh to other servers when root:
User <my-username>
Add wordclock- AWS credentials to /root/.aws/credentials:
[default]
aws_access_key_id = <key>
aws_secret_access_key = <secret>
Using raspi-config, enable i2c.
Get the contents of this repo onto the Pi.
cd /home/pi
git clone git@github.com:marksidell/wordclock.git
Create a custom config-<xx>.py file for your particular clock. The config files are stored
in the config directory.
Do one-time setup. This assumes you've modified the authorized_keys file to permit login with your own key pair.
cd <repo>/code
sudo make config_sshd
sudo make setup
Install everything:
cd <repo>/code
sudo make all [CONFIG=<config-file-base-name>] [S3_BUCKET=<s3-bucket-name>]
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