There are several methods for measuring pH. The most common is the use of a glass electrode sensible to it, a reference electrode and a measurement device. Another method is the use of indicators and colorimeters. Indicators are materials specifically designed to change color when they are exposed to different pH levels. The colorimeter is a device that utilizes a container filled with a determined volume of sample to which a reactive is added. Afterwards, the mixture changes color and is ready to be compared in a color wheel or a standard spectrum of color with the purpose of interpolating the resulting value [12]. pH electrodes normally consist of two main parts: the measurement electrode and the reference one. The first normally called glass electrode or active electrode. The second is also called standard electrode [12].
C. ZigBee for Water Quality Monitoring The ZigBee protocol is a wireless technology that was …show more content…
The system consist of 3 parts: data monitoring nodes, base station, and a remote monitoring system. The nodes recollect pH and temperature parameters. The system is also capable of using linearization and temperature compensation, data packaging, recollected data memorizing and routing to base station. These data is transported to a remote monitoring center through a GPRS network. The remote monitoring center analyzes the data and generates alarms for emergencies like water pollution or sudden changes in water parameters. The system shows useful characteristics, like large network capacity, low power consumption and minor environmental