pi_watch

A project to make a pi small enough to wear on your wrist as a watch. It can check buses near my apartment, show the weather, and turn off with button presses. You can see a youtube video showing off the project here.

I bought a watch case for the pi here and an e-ink display from papirus here. The e-ink display has 5 buttons on it which is quite handy!

Setup Steps

To set this up, you'll need to set the pi up. I wrote a guide on that you can find here. You'll then need to solder some headers to the pi zero and put the e-ink display on top of it.

Then, you'll need to download a font to your home directory on the pi, or make peace with the default font. I like https://fonts2u.com/nasalizationrg-regular.font.

From here you can clone this repo, then edit the scripts/auto_watch.py file to put the path to your font in the font_path variable.

If your username is jack, and you want to run the watch script without sudo permission, you'll need to add jack to some user groups:

sudo adduser jack gpio
sudo adduser jack dialout
sudo adduser jack i2c

You'll need to enable i2c and spi communication in raspi-config interface options

sudo raspi-config

You'll also need to follow the instructions on PaPiRus's github to install their API. Find it here: https://github.com/PiSupply/PaPiRus

You'll need to install the libraries I used to make the transit checker and weather checker, to whatever user you run want to run the command as. I run as sudo, so I install for sudo.

sudo pip3 install -r requirements.txt

From here you can edit your sudo crontab (if you're running command as sudo) and add a command on reboot to startup the script. If you don't want to call the 511 bay area api to check buses, then you can put in your511apikey instead of a real api key.

sudo crontab -e

add this to the bottom. Be sure to create the watch-cron_log.log file and put the path to it. This will get stderr redirected to it to help debug if stuff goes wrong.

@reboot python3 /home/mikey/Documents/pi_watch/scripts/auto_watch.py your511apikey 2>> /home/jack/logs/watch_cron_log.log &

Adding your Phone's wifi hotspot as secondary network

Thanks to this stack overflow post here, the below shows the file to edit:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

And you can add your two networks wiht something like the below. Note that a higher number is a higher priority. Also note I had to comment out any of my changes (to do static ip stuff) to /etc/dhcpcd.conf to get my pi to connect to my mobile hotspot.

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=US

network={
        ssid="network1"
        psk="password1"
        id_str="home"
        key_mgmt=WPA-PSK
        priority=2 # higher priority than 1
}

network={
        ssid="network2"
        id_str="mobile"
        psk="password2!"
        key_mgmt=WPA-PSK
        priority=1 # lower priority than 2
}

Notes on the Scripts

I used 511 SF Bay’s Portal for Open Transit Data to get the buses in my hometown of San Francisco. You can find info on that API and how to create a token here. In the get_transit.py code I document some useful links to resources for finding stop ids and navigating the datastructure.

Troubleshooting

If sometimes you start your pi and the auto watch script doesn't come on, redirect the output in the crontab to a log file. This will capture any errors on startup. If you see something like the below, it's likely device service isn't running when the papirus initializes, and you could fix it by adding a sleep to the top of the script. 20 seconds is probably long enough, as per: PiSupply/PaPiRus#14

CRITICAL:root:[Errno 2] No such file or directory: '/dev/epd/version'
Traceback (most recent call last):
  File "/home/mikey/Documents/pi_watch/scripts/auto_watch.py", line 102, in <module>
    text = PapirusTextPos(rotation=0)
  File "/usr/local/lib/python3.5/dist-packages/papirus/textpos.py", line 25, in __init__
    self.papirus = Papirus(rotation=rotation)
  File "/usr/local/lib/python3.5/dist-packages/papirus/epd.py", line 83, in __init__
    with open(os.path.join(self._epd_path, 'version')) as f:
FileNotFoundError: [Errno 2] No such file or directory: '/dev/epd/version'