coot
CO2 IoT monitor.
coot
CO2 IoT monitor.
Cross-compiling with raspi-toolchain
On the target device (Raspberry Pi 1, arm6)
This guide assumes you are using an ARMv6 processor, which is found on:
- Raspberry Pi 1
- Raspberry Pi Zero W
To confirm this is compatible with your device, check the model name of the CPU:
$ cat /proc/cpuinfo
processor : 0
model name : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS : 697.95
Features : half thumb fastmult vfp edsp java tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xb76
CPU revision : 7
Hardware : BCM2835
Revision : 9000c1
Serial : 000000004698d2d8
Model : Raspberry Pi Zero W Rev 1.1
Install required system libs:
# note: you don't have to install libc on Raspberry Pi Zero W
# it should already be installed by the system as libc6
sudo apt-get install libhidapi-libusb0 libhidapi-dev libc
On the compiling machine
Sync target libs
Pull system libs from the target machine for linking:
export PI_HOSTNAME=dewberry
export ROOTFS=/home/tom/$PI_HOSTNAME/rootfs
mkdir -p $ROOTFS
rsync -vR --progress -rl --delete-after --safe-links pi@$PI_HOSTNAME:/{lib,usr,opt/vc/lib} $ROOTFS
# Add a symlink here to match an expected filepath from libhidapi
(cd /home/tom/dewberry/rootfs/usr/lib/arm-linux-gnueabihf; ln -s libhidapi-libusb.so.0 libhidapi-libusb.so)
Configure cross-compile toolchain
Install the raspi-toolchain compiler.
cd /tmp
wget https://github.com/Pro/raspi-toolchain/releases/latest/download/raspi-toolchain.tar.gz
sudo tar xfz raspi-toolchain.tar.gz --strip-components=1 -C /opt
rm /tmp/raspi-toolchain.tar.gz
Setup cargo to use an external linker:
# ~/.cargo/config.toml
[target.arm-unknown-linux-gnueabihf]
linker = "/opt/cross-pi-gcc/bin/arm-linux-gnueabihf-gcc"
Compile!
Compile the crate, pointing the linker to the correct locations for system libs.
export TOOLBIN=/opt/cross-pi-gcc/bin
export STAGING=/opt/cross-pi-gcc/arm-linux-gnueabihf
export HOST=arm-linux-gnueabihf
export CC=$TOOLBIN/arm-linux-gnueabihf-gcc
export CXX=$TOOLBIN/arm-linux-gnueabihf-g++
PKG_CONFIG_ALLOW_CROSS=1 cargo rustc --release --target arm-unknown-linux-gnueabihf -- \
-C linker=$CC/arm-linux-gnueabihf-gcc -L $STAGING/lib \
-C link-arg=-Wl,-rpath-link,$STAGING/lib -L $ROOTFS/lib \
-C link-arg=-Wl,-rpath-link,$ROOTFS/lib -L $ROOTFS/usr/lib/$HOST \
-C link-arg=-Wl,-rpath-link,$ROOTFS/usr/lib/$HOST -L $ROOTFS/lib/$HOST \
-C link-arg=-Wl,-rpath-link,$ROOTFS/lib/$HOST
See example cmake file for complete list of linking locations: https://github.com/Pro/raspi-toolchain/blob/master/Toolchain-rpi.cmake
Deploy
Copy the output to the target machine.
scp target/arm-unknown-linux-gnueabihf/debug/coot pi@dewberry:~
Installation
udev Rules
See guide on how to setup udev rules here. Essentially:
echo 'ACTION=="add|change", SUBSYSTEMS=="usb", ATTRS{idVendor}=="04d9", ATTRS{idProduct}=="a052", MODE:="0666"' | sudo tee -a /etc/udev/rules.d/60-co2mon.rules
sudo udevadm control --reload
sudo udevadm trigger
Run
Ensure you have a configuration file coot.yml in the working directory. See example for a sample.
Run like ./coot >> coot.jsonl 2>> coot.log. Data will be output to coot.jsonl as well as uploaded to InfluxDB.
Log rotation
You should set up log rotation like:
# /etc/logrotate.d/coot
/home/pi/coot.jsonl {
daily
missingok
rotate 3650
compress
copytruncate
}
/home/pi/coot.log {
weekly
missingok
rotate 4
compress
copytruncate
}
Running as a service
If you want to run coot detached as a service, that will reboot when the pi does, you can copy the coot.service file in the repo:
sudo cp coot.service /etc/systemd/system/
sudo systemctl enable coot
sudo systemctl start coot
You can then monitor it's progress with:
sudo systemctl status coot
Other resources
TODO: pull these together to be more than just a tabdump