D3noob.org Website Review

MULTIPLE TEMPERATURE MEASUREMENTS WITH THE DS18B20 ON THE RASPBERRY PI. This project will measure the temperature at multiple points using DS18B20 sensors. We will use the waterproof version of the sensors The DS18B20 is a ‘1-Wire’ digital temperature sensor manufactured by Maxim Integrated Products Inc. It provides a 9-bit to 12-bit precision, Celsius temperature measurement and incorporates an alarm function with user-programmable upper and lower trigger points. It is called a ‘1-Wire’ device as it can operate over a single wire bus thanks to each sensor having a unique 64-bit serial code that can identify each device. While the DS18B20 comes in a TO-92 package, it is also available in a waterproof, stainless steel package that is pre-wired and therefore slightly easier to use in conditions that require a degree of protection. The measurement project that we will undertake will use the waterproof version. The sensors can come with a couple of different wire colour combinations. They will typically have a black wire that needs to be connected to ground. A red wire that should be connected to a voltage source (in our case a 3.3V pin from the Pi) and a blue or yellow wire project we will use an external voltage supply (from the Pi). The DS18B20 sensors needs to be connected with the black wires to ground, the red wires to the 3V3 pin and the blue or yellow (some sensors have blue and some have yellow) wires to the GPIO4 pin. A resistor between the value of 4.7k Ohms to 10k Ohms needs to be The Raspbian Operating System image that we are using only supports GPIO4 as a 1-Wire pin, so we need to ensure that this is the pin that we use for connecting our temperature sensor. The following diagram is a simplified view of the connection. bread board connected to the GPIO pins. But because the connection is relatively simple we could build a minimal configuration that will resister is concealed under the heat-shrink and indicated with the arrow.