## 3 Communication in IoT
### Commonly Used Sensors for Smart Farming and Heavy Metal Identification
\begin{table}
\begin{tabular}{c c c} \hline \hline
**No. \#** & **Sensor Name** & **Functionalities** \\ \hline
13 & Arduino and RPi-based potentiostat & Supports on-site heavy metal detection with integration of soil moisture and temperature sensors \\
14 & HMstat & Supports on-site heavy metal detection with built-in ADC and DAC; compatible to incorporate soil moisture and temperature sensors \\
15 & BetaTherm 100K6A1B thermistor & Temperature sensor (photosynthesis process) \\
16 & S-LWA-M003 & Leaf wetness sensor \\
17 & \(\Delta\)LA-C (AT Leaf-to-Air-Conifer type) & Precise sensor for leaf temperature \\
18 & BH1750 FVI Digital Light Intensity Sensor & Light intensity sensor \\
19 & MG811 Carbon Dioxide CO\({}_{2}\) Sensor & CO\({}_{2}\) sensor \\
20 & LW100, leaf wetness sensor & Plant moisture, plant wetness, plant temperature \\
21 & LT-2 M, LT-1P (leaf temperature sensor) & Leaf temperature measurement \\
22 & HOBO S-LIA-M003 Photosynthesis & Photosynthesis and soil moisture measurement \\
23 & ST-340 photosynthesis system & Photosynthesis, plant moisture, air temperature, air humidity, plant wetness, CO\({}_{2}\), plant temperature, hydrogen level in plant \\
24 & RTH-11, RTH-48 & Photosynthesis and leaf wetness sensor \\
25 & FI-LP, FI-MP, FI-SP & Fruit growth sensors \\
26 & SA-20P Auxanometer & Plant growth measurement \\
27 & SD-SP, SD-6P & Measurement for micro stem variation \\
28 & Veris 3100 & Accurately map soil variability \\
29 & Extech EC400 & To measure conductivity, total dissolved solids, salinity, and temperature \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._  
Figure 6: (**a**) Pictorial description of BTnode. (**b**) Illustration of BTnode [159]. Epic is a new open mote platform for SensorNet modules. Pictorial view of Epic is shown in Figure 7. SensorNet platforms, like most embedded systems, are tightly coupled to their applications and this can also be incorporated over parallel programming paradigm to enhance processing and reduce execution time [161; 162]. A key aspect of Epic is the support of prototyping and reusability using composable hardware architecture. The research and development of Epic was carried out at Computer Science Division, University of California, Berkeley, in 2008 [161]. Irene Mote was an advanced stage development of Epic with numerous functionalities which makes it suitable to implement user-centric studies. The research and development of Irene Mote was carried out at Computer Science Division, University of California, Berkeley, in 2009 [163; 164; 165]. Figure 8 shows the pictorial representation and illustration of Irene Mote. Figure 8: Pictorial description and illustration of [PERSON] [164; 165]. Figure 7: Pictorial description of Epic [161]. The CM5000 TelosB sensor was developed to measure temperature, relative humidity, and light intensity. The sensor is IEEE 802.15.4 compliant wireless sensor node based on the original open source TelosB/Tmote Sky platform design which was developed by the University of California, Berkeley [164; 166; 167]. Figure 9 shows the pictorial description of CM5000-TelosB sensor. The Preon32 module is tailored for short-range wireless networks and is equipped with a universally usable sensor and actuator platform [169; 170]. Figure 10 pictorially represents the Preon32 sensor. Preon32 is incorporated with Cortex-M3 controller which is compatible with IEEE 802.15.4 radio frequency module. In addition, this module enables developers to develop the wireless module codes using an object-oriented programming language like Java [169]. It also demonstrates the functionalities of external interfaces, i.e., USB, CAN, and SPI, etc. [164; 169]. The Mica2 Mote is shown in Figure 11. These motes are CrossBow Technology's mote technology of the second and third century. In combination with the CC1000/CC2420 RF Module, Mica2 and MicaZ use the Atmega128L controllers [171]. With the interface  
Figure 10: Preon32 sensor [170]. Figure 9: Pictorial description of CM5000-TelosB [164; 168].