Code Project’s George Swan has a very simple and straightforward tutorial for setting up “a two-way interface between a remote browser-enabled device and a Raspberry Pi.” The remote device could be your cellphone, for example, and the sensor for this example is a DS18B20 digital temperature sensor, and multiple on/off switches are demonstrated. It doesn’t get much easier or straightforward than this:

The project uses a Raspberry Pi 3 running the latest version of Raspbian with internet enabled WiFi. You can use earlier versions of the Pi, however, the port pin numbers may not correspond to the ones mentioned here. The Pi needs to have a few interfacing connections enabled. This used to be a long and tedious business but it has now been greatly simplified. The easiest way to connect the Pi’s HDMI cable to a monitor, attach an internet connected Ethernet cable, a usb keyboard and mouse and boot to Raspbian. From the raspberry icon on the top left of the screen, select preferences/raspberry Pi configuration/interfaces and enable SSH, 1-Wire and Remote GPIO, then close the pop up window. To enable WiFi, click on the up/ down arrows icon on the top right of the screen and follow the prompts . Remove the Ethernet connection, then, click on the command window icon and enter the command ‘hostname –I’. Make a note of the IP address that’s displayed, you’ll need it to connect to the Pi. Then reboot the Pi. (enter ‘reboot’).

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And be sure to check out our assortment of DS18B20 sensors, from a basic TO-92 package suitable for breadboard prototyping and through-hole PCBs to fully-encased waterproof and high-temp waterproof housings: