greenhouse-hyrdoponics

An experiment in automation.

Background Information on Device Configuration

Device: Raspberry Pi Zero 2 W

OS: Raspberry Pi OS Lite (32-bit), released 2022-04-04. A port of Debian Bullseye with no desktop environment.

Note: The following assume a headless instance of the Raspberry Pi OS and so the following notes only refer to driving changes through the command line or config.txt file.

1-Wire (W1) Protocol

By default the Raspberry Pi OS disables the 1-Wire interface. To use sensors such as the DS1820 we need to re-enable it.

To enable the interface modify the config.txt:

sudo nano /boot/config.txt

Add the following after the last line in the file:

dtoverlay=w1-gpio

The default BCM4 is 4.

To activate the protocol on one or more custom pins use:

dtoverlay=w1-gpio,gpiopin=4
dtoverlay=w1-gpio,gpiopin=24

Then reboot the Pi for the changes to take effect, sudo reboot.

Run the following commands to pick up the attached 1-Wire temperature sensors:

sudo modprobe w1-gpio
sudo modprobe q1-therm

Run the following to list the found devices:

ls /sys/bus/w1/devices/

Reducing Power Consumption

Initially developed on the RPi 3b+ it was quite power hungry and the following were useful to reduce device power usage by a new milliamps. The setup is now running on a Pi Zero 2 which has a lower overall power consumption.

Disable on board Bluetooth

List Bluetooth devices by running:

hciconfig

If you have any onboard or connected chips you will see output similar to the following:

hci0:   Type: Primary  Bus: UART
        BD Address: B8:27:EB:72:17:A5  ACL MTU: 1021:8  SCO MTU: 64:1
        UP RUNNING 
        RX bytes:1562 acl:0 sco:0 events:96 errors:0
        TX bytes:2574 acl:0 sco:0 commands:96 errors:0

Note: In this example the device is UP.

You can see the list of available hciconfig options by running hciconfig -h, for our purposes we are focusing on the up and down arguments.

To disble the Bluetooth device run the following, using the desired up/down state and device id, e.g.

sudo hciconfig hci0 down

Disable on board LEDs

The following settings when added to the config.txt will disable the Power, Activity and Network activity LEDs. Reboot after applying these to have them take effect.

# Turn off Power LED
dtparam=pwr_led_trigger=none
dtparam=pwr_led_activelow=off
# Turn off Activity LED
dtparam=act_led_trigger=none
dtparam=act_led_activelow=off
# Turn off Ethernet ACT LED
dtparam=eth_led0=14
# Turn off Ethernet LNK LED
dtparam=eth_led1=14

Note: These work for the RPi 3, but the Pi 4 'eth' ids are different.

Acknowledgements

1-Wire configuration: https://www.raspberrypi-spy.co.uk/2018/02/enable-1-wire-interface-raspberry-pi/
Onboard LED configuration: https://smarthomescene.com/guides/how-to-disable-leds-on-raspberry-pi-3b-4b/
INA219 Setup: https://pypi.org/project/pi-ina219/
Power Consumption Benchmarks: http://www.pidramble.com/wiki/benchmarks/power-consumption