![]() Using “cd” we can change to the temperature sensor directory, list the contents and then view the “w1_slave” file : ![]() Your ID will be different so be sure to use that in the example code below. Get Sensor IDĮach sensor has a unique ID and in my case it is 28-00000482b243. This will list the directories associated with your 1-wire devices. Use the commands below to go to the directory that contains the detected 1-wire devices : The device is setup to report its temperature via GPIO4.įor the changes to take effect you will need to reboot using : sudo reboot Check for Connected Devices You can save the file using CTRL-X, Y then RETURN. In order to enable the 1-Wire interface you just need to make a small change to the config.txt file using : sudo nano /boot/config.txtĪdd the following line to the bottom : dtoverlay=w1-gpio,gpiopin=4 This needs to be enabled so either follow the instructions below or refer to the Enable 1-Wire Interface on the Raspberry Pi post. The DS18B20 sensor uses the 1-Wire protocol. OPENSPRINKLER WIRING UPGRADESudo apt-get upgrade Enable 1-Wire Interface OPENSPRINKLER WIRING UPDATEI tend to use the latest Raspbian image from the download page and then update it from time to time using the following two commands : sudo apt-get update It’s always best to tackle new projects with an updated SD card. Once you have connected everything together you can power up your Raspberry Pi. Sensor Pin 2 connected to P1-07 (GPIO4)Ī 4.7Kohm resistor was placed between Sensor pin 2 and 3.ĭouble check that you don’t confuse Pin 1 and Pin 3 on the device otherwise the power will be applied the wrong way round!.Sensor Pin 1 connected to P1-06 (Ground).I used a small piece of breadboard and some jumper cables to connect it to the GPIO header on my Raspberry Pi. In my testing I didn’t have one of these so I used 2 x 2.2Kohm resistors in series. The only external component required is a single 4.7Kohm resistor. ![]() Pin 2 is the data pin and Pin 3 is the power pin. ![]() It has three pins and comes in a TO-92 package which means it looks similar to other devices you may have used such as transistors. The diagram on the right shows the DS18B20 device. It is so simple to use and the perfect starting point for creating a Raspberry Pi based temperature data logger. Within a few minutes I was measuring the temperature with it. The device only cost a few pounds and it seemed too good to be true … This promised an accurate way of measuring temperature with a few wires and almost no external components. While searching for a simple way to measure temperature using my Raspberry Pi I came across the DS18B20 1-wire digital temperature sensor. ![]()
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