Ruuvitag Reader for Raspberry Pi Zero W

This is the repository for preparing a Raspberry Pi Zero W for reading Ruuvitag messages.

Prerequisites

• Ruuvitag
• Raspberry Pi Zero W
• Micro SD -cardreader

Quickstart

Writing a pre-made image

On OSX run the following command to find out which disk the SD card is diskutil list. Check which disk is the SD card (e.g. /dev/disk2). NOTICE: If you write on a wrong disk, you will lose data.

Then unmount that disk diskutil unmountDisk /dev/diskX, where diskX is the disk you picked from the previous command.

Download the ready-made Raspberry Pi Zero -image wget https://www.dropbox.com/s/egl2t7r0143natx/ruuvitag-raspberrypi-zero-20200126.img.gz.

Finally write it one the SD card gunzip -c ruuvitag-raspberrypi-zero-20200126.img.gz | sudo dd bs=1m of=/dev/rdiskX. Prepend disk with r.

For /dev/disk2 this would be:

wget https://www.dropbox.com/s/egl2t7r0143natx/ruuvitag-raspberrypi-zero-20200126.img.gz
diskutil unmountDisk /dev/disk2
gunzip -c ruuvitag-raspberrypi-zero-20200126.img.gz | sudo dd bs=1m of=/dev/rdisk2

Now you are ready to unmount the SD card, insert it into your Raspberry Pi and Boot.

Reading Ruuvitag

SSH into the Pi with ssh -i keys/pi.pem pi@<ip address>, where ip address is the address of your Raspberry Pi.

Create a directory and cd into it, e.g. mkdir ruuvi && cd ruuvi.

Link the globally installed node-ruuvitag with npm link node-ruuvitag.

Open node console (with node) and copy-paste the following code:

const ruuvi = require('node-ruuvitag');

ruuvi.on('found', (tag) => {
  console.log(`Found RuuviTag with id: ${tag.id}`);

  tag.on('updated', (data) => {
    console.log(`${tag.id}: ${JSON.stringify(data)}`);
  });
});

Once you press enter you will see the logging from nearby ruuvitags.

NOTICE: You can also copy the content of src/index.js into the directory you created and run it with node index.js.

Creating the image

Prerequisites

• Docker
• Ansible

Writing Raspbian on the SD card

Download Raspbian Lite (Buster at the time of writing).

On OSX run the following command to find out which disk the SD card is diskutil list. Check which disk is the SD card (e.g. /dev/disk2). NOTICE: If you write on a wrong disk, you will lose data.

Then unmount that disk, where diskX is the disk you picked from the previous command.

diskutil unmountDisk /dev/diskX

Format the disk using diskX as the same disk as in the previous command.

sudo newfs_msdos -F 32 /dev/diskX

Finally write the raspbian image on the disk with the command below. Notice that the disk is prepended with a letter r. Using the raw disk for writing makes writing the data much faster.

sudo dd bs=1m if=2019-09-26-raspbian-buster-lite.img of=/dev/rdiskX

Enabling Wifi and SSH

To enable SSH on the Raspberry on boot time, add an empty file called ssh into the /boot partition of the SD card. You will find such file in the boot-directory of this repository, but you can also create it with e.g. touch /boot/ssh.

To enable Wifi, modify the boot/wpa_supplicant.conf with your locale and Wifi information, and add it to the /boot partition of the SD card. NOTICE: Raspberry Pi Zero does not support 5GHz wifi.

To disable ipv6, add ipv6.disable=1 to the end of the first line of the cmdline.txt-file in the /boot partition of the SD card. You will find a pre-made cmdline.txt for the current Buster (2019-09-26 at the time of writing) in the boot-directory.

Generating an SSH key for accessing the Raspberry Pi

To generate an SSH secret key, run openssl genrsa 4096 > pi.pem. Then change the access control so that its not accessible to others chmod 600 pi.pem.

Next generate a public key from the secret key ssh-keygen -y -f pi.pem > key.pem.pub.

Now you are ready to unmount the SD card, insert it into your Raspberry Pi and Boot.

NOTICE: Remember to change the default password on the first login.

Provisioning

Once the Raspberry Pi has booted and you know its ip-address (either attach a screen, do an ip scan or see your router admin), it is time to provision the Raspberry Pi Zero. This guide will refer to this address as <ip address>.

Add your SSH key to authorized keys

First add the key you generated previously as a trusted key by running ssh-copy-id -i pi.pem pi@<ip address> and using the default password. Remember to change your password. You can also remove password login from SSH altogether by setting PasswordAuthentication no in the configuration file /etc/ssh/sshd_config and either rebooting your Pi, or the SSH service (using sudo service ssh restart).

You can also login to your Pi with ssh and add the contents of pi.pem.pub to ~/.ssh/authorized_keys, but ssh-copy-id will do that for you easier.

Provision your Raspberry Pi

Copy the hosts.example -file to e.g. hosts.local and replace <ip address> with the ip address of your Pi.

Now you are ready to run:

ansible-playbook provisioning/playbook.yml -i provisioning/hosts.local

Storing and shrinking the image for cloning

Once the ansible provisioning is ready you can detach the SD card and attach it to your computer.

Create an image of the SD card. Remember to replace the X with the disk number found from diskutil list, and use whatever filename.

sudo dd bs=1m if=/dev/rdiskX of=ruuvitag-raspberrypi-zero.dmg

To shrink the image, and make it autoexpandable, clone the PiShrink-repository, build the dockerimage (by running docker build -t pishrink . in the repository folder) and then run the following command (replace the filenames to whatever you want):

docker run --privileged -v $(pwd):/root pishrink -z ruuvitag-raspberrypi-zero.dmg ruuvitag-raspberrypi-zero-shrunk-and-compressed.img

Now you can write the shrunk image to a new SD card as shown above in the quickstart:

gunzip -c ruuvitag-raspberrypi-zero-shrunk-and-compressed.img.gz | sudo dd bs=1m of=/dev/rdiskX`.