Setting up the 1-wire interface for the RPi
- Page ID
- 40068
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Setting up the 1-wire interface using the DS18B20 Temperature Sensor.
First enable the 1-wire interface on the RPi.
The following link demonstrates three methods for enabling 1-Wire Interface on the Raspberry Pi.
https://www.raspberrypi-spy.co.uk/2018/02/enable-1-wire-interface-raspberry-pi/
Methods, 1 and 2 use ‘sudo raspi-config’ or the GUI to enable 1-Wire.
Using ‘sudo raspi-config’ or the GUI will setup the default Pin 7 (GPIO4) port.
Method 3 shows how to enable 1-Wire Interface by editing the /boot/config.txt.
Understanding the manual editing of the /boot/config.txt file is essential for connecting two 1-Wire devices.
In the following example two gpiopins are initialized for 1-Wire interface, gpiopin=4 and gpiopin=5.
pi@aquaponics$ tail -6 /boot/config.txt [all] #dtoverlay=vc4-fkms-v3d dtoverlay=w1-gpio,gpiopin=4 dtoverlay=w1-gpio,gpiopin=5
If only one 1-Wire Interface is needed the following methods can be used;
Activate the 1-wire interface as shown here;
Enabling the 1-wire interface can also be accomplished remotely using ssh on the terminal.
sudo raspi-config
Activate the 1-wire interface as shown here;
After enabling the 1-Wire Interface by any method a reboot is required.
Attached the DS18B20 to the breadboard as shown in the following link;
https://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing?view=all
A 4.7K resistor is required, see wiring in the link above.
Attached 1-Wire devices can be listed with the following command;
ls /sys/bus/w1/devices/
For this example two DS18B20 sensors are shown.
pi@aquaponics$ ls /sys/bus/w1/devices/ 28-3c01b5569d9e 28-3c01b556bce8 w1_bus_master1 w1_bus_master2
The IDs for the two are 28-3c01b5569d9e and 28-3c01b556bce8.
These IDs are required for collecting data from the sensors.
The python script used in this example was found here;
https://www.raspberrypi-spy.co.uk/2013/03/raspberry-pi-1-wire-digital-thermometer-sensor/
The wget command can be used to download the python script.
wget https://bitbucket.org/MattHawkinsUK/rpispy-misc/raw/master/python/ds18b20.py
Note: in the python script ds18b20.py replace the device ID 28-00000482b243 with the ID for the device you are using.
The following link demonstrates how to setup one gpio port for several 1-wire devices.
https://raspberryautomation.com/connect-multiple-ds18b20-temperature-sensors-to-a-raspberry-pi/
The following fritzing diagram was found in the above link.
Note: when one of the two DS18B20 sensors failed the solution was to shut-down the RPi and reseat the pins into the breadboard. Both sensors were again showing up in the system.