7-03 Accelerometer Data Transmission Based On Wireless Sensor Network ACCELEROMETER DATA TRANSMISSION BASED ON WIRELESS SENSOR NETWORK

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1 7-03 Accelerometer Data Transmission Based On Wireless Sensor Network ACCELEROMETER DATA TRANSMISSION BASED ON WIRELESS SENSOR NETWORK Hafsah Nirwana 1), Zahir Zainuddin 2), Ibrahim Abduh 3), Muh.Tola 4), N Harun 5), M.Bakri M 6) 1) Mahasiswa Program Doktor Teknik Sipil, Universitas Hasanuddin 2,4,5) Dosen Jurusan Teknik Elektro Universitas Hasanuddin 3) Dosen Jurusan Teknik Elektro Politeknik Neg. UP 6) Dosen Teknik Sipil Universitas Hasanuddin yayeng555@yahoo.co.id ABSTRACT The design of the system consists of two parts, namely the node sensor and the sink node. The sensor node is placed in the location which monitors slope level and serves as reader of ground surface movement. In this part exists accelerometer sensor (MMA7361L) to monitor the movement of ground surface and provide warning in alarm sound based on monitoring related with the development of ground movement. This early warning system sensitivity can be adjusted according to the needs in the field by inserting slope limitation range of transmitter position. The alarm will sound when ground surface moves that change the system to slope position beyond the threshold limitation. The data of sensor node slope are then sent to the sink node via wireless Zigbee protocol. From sink node, the data is sent to a computer via serial port and displayed graphically so that the monitoring of ground movement can be made at any time. Delphi 7 software is used as an interface to monitor the movement of ground. afterwards the data is sent using the WSN devices. The data is sent continuously and real time. If there is ground movement that allows the landslide will happened then receiver as monitoring center will be sounded as early warning alarm[10]. Communication in sensor network does not require large bandwidth because the information that would be sent only in the form of data recitation at each sensor and distance range of transceiver which is used relatively close[8]. In WSN, the sensor nodes (sources) diffused in order to capture any symptoms or phenomenon that is intended for research. The amount number of diffused nodes can be determined according to the needs and depends on several factors such as area size, the ability of sensing nodes, and so on. Each node has the ability to collect data and route the data return to the Base Station. Sensor nodes can collect large amounts of data from the symptoms that arise from the surrounding environment. 1. Introduction Wireless technology facilitates us to use it as environmental monitoring, include the monitoring of natural disasters such as landslides. The process of monitoring the occurrence of landslides can be done using Wireless Sensor Network technology/ WSN (Wireless Sensor Network/WSN). One of the methods is by reading the shudder on the surface of the soil as well as inside the soil. Soil movement data obtained from accelerometer sensors Figure 1. Wireless Sensor Network Architecture[7] Data is sent via radio transmission forwarded towards the BS (Base Station), which is a connector between sensor node and user. Such information can be accessed through a variety of platforms such as the Internet or satellite connection 233

2 The Proceedings of The 7th ICTS, Bali, May 15th-16th, 2013 (ISSN: ) allowing user to access via remote server in real time. The module used for the application of WSN is XBee S1. XBee is a module designed to meet ZigBee / IEEE standard is used for low-cost and low-power sensor network. These modules require minimal power and provide reliable data transfer between two devices[3]. Xbee RF Module is a radio frequency module operating at a frequency of 2.4 GHz. Offset accelerometer voltage is influenced by sensor orientation and static acceleration of each axis due to the force of gravity. For positive acceleration the output signal will increase in the voltage offset, while for negative acceleration the output signal will decrease under voltage offset[5]. 2. Research Methods Systematic design of this research can be seen in figure 4 below. MMA7361L ATMEL8535 LCD MAX232 Xbee (TX) WIRILESS Komputer (monitorinr) Xbee (RX) Figure 2. RF Transceiver 2.4 GHz Xbee[3] MMA7361L accelerometer sensor consists of three axes of measurement, namely the x-axis, y-axis and z-axis. The accelerometer sensor is used to measure the acceleration of the object in units of gravity(g) [5]. This sensor can measure two accelerations namely 1.5g and 6g. The figure of MMA6371L accelerometer sensor can be seen in Figure 3 below. Figure 3. MMA7361L Accelerometer Sensor[5] MMA7361L accelerometer sensor can be used to measure the acceleration of both positive and negative acceleration. When the sensor is at stagnant condition, the output of the sensor on the x-axis will produce offset voltage half which amount half from input sensor (VOFFSET = VDD ) Figure 4: Block Diagram Design The design is implemented on a communication Wireless Sensor Network consists of node sensor (data sources) and node sink (data processing). Node sensor which is the data in digital form of slides from accelerometer sensor, while sink node will display the landslide data on a computer by using software. MMA7361L accelerometer sensor is a sensor used to measure acceleration, detect and measure shudder, and measure the acceleration due to gravity. Accelerometer sensor measures the acceleration due to movement of objects attached to it an example of soil recitation. Accelerometer sensor can measure by three axes of measurement, namely towards the x-axis, y-axis and z-axis. The output of this sensor analog scale will be processed in the microcontroller. In the microcontroller unit form of IC ATMega8535L, the input from the sensors initially analog scale will be converted into digital scale. Then instruct the result of measurement from the sensor to be

3 Accelerometer Data Transmission Based On Wireless Sensor Network displayed on the LCD size 16x2. Besides that, microcontrollers also instructed to XBee module to send the result of data sensoring continuously with 500 ms delay. Before Microcontroller is connected to XBee it needs MAX232 circuit to equalize voltage level between microcontroller and Xbee. Data in the form of landslides digital scale then processed by XBee. At XBee there is oscillator that serves to generate frequency of 2.4 GHz is used to modulate the signal.moreover,in XBee module there is also a process of framing. Information is input in the frame is composed of parity bits, and addressing. Once the data is ready to be transmitted, the XBee antenna then transmits the signals. Next on the sink node side, the data that has been transmitted from the sensor nodes are expected to be well received by the Xbee module then check the address and modulate the received signal. After that the data received is displayed to computer/laptop using delphi 7. In delphi program range command are input namely upper and lower limits of slope accelerometer sensor for the X axis and Y axis. The scoring range aims to give the value of tolerance threshold shift or movement of land is still considered safe before the movement and shifting ground which potentially erosion. When the actual value of the slope is outside these limitation (it means, a shift has occurred and the movement of the ground outside the tolerance is safe), then the alarm will sound. This shows that there has been a shift in land which is dangerous. 3. Result Tests conducted several stages: MMA7361L accelerometer testing, XBee RF Transceiver 2.4 GHz testing, and system integration testing. Measuring the output voltage of the three-axis accelerometer measurement is performed when the accelerometer is accelerating static (stagnant). The Purpose of this measurement is to ensure that offset value of three-axis accelerometer measurement is half of the value of VDD. V OFFSET = VDD 2 Where VOFFSET none other than the output voltage measurement when the axis accelerometer measurements are at 0g, accelerometer sensor means that the position is right in a vertical straight line. Test results can be used to express the change in the unit of gravitational acceleration (g) where the results using value VOFFSET is equivalent to measure 0g. The Measurement was taken using a digital multimeter recitation by two decimal places, and measured the VDD of accelerometer used is at VDD = 3.32 volt. The result setting or trial of MMA7361L accelerometer devices can be seen in Figure 5 below Figure 5. Graphs of accelerometer sensor output voltage measurement Testing communication device directly integrated with accelerometer device. The process of data recitation of accelerometer shudder condition is sent via the Wireless Sensor Network. The test is performed by taking the distance of 20m, 40m, 60m, 80m, 100m, and the last 130 meters of the node sensor to the sink node. At a distance of 20 to 40 meters, data transmission to the sink node is still very stable and almost no data loss. Up to a distance of 60 m it was 235 x y z

4 The Proceedings of The 7th ICTS, Bali, May 15th-16th, 2013 (ISSN: ) found that data loss is not too large, this causes by the tree barrier of node sensor to the sink node. At a distance of 100 data receive is slow due to increasing of distance measurements. Up to 130 meters at a distance of data received by the sink nodes get smaller and sometimes delayed for a long period of time. shudder condition If in conditioning your accelerometer slope position 25 0 then received data will be display as Figure 8. It can be conditioned that landslides will occur. If the data is received as this, the automatic alarm device will sound to provide information that landslides will occur. The data results display for a variety of accelerometer condition which is received at sink node can be seen in some figures 6 below. Figure 8. Accelerometer data slope angle of 25 0 Figure 6. Accelerometer data in Xout loss condition Xout data condition occurs when there is loss data, a condition in which data loss occurs due to such things as increasing the distance range, the barrier between the node sensor and the sink node and others. While, accelerometer data in shudder condition, then the data will be received as Figure 7 below. From the above test results, namely by taking a safe condition and landslides will occur, the resulting signal has a significant difference. Signal Xout, Yout and Zout of accelerometer in safe condition means stable output signal switching between reference signals followed by the signal amplitude almost nothing changes happened. While the measurement of signals Xout, Yout and Zout on occurance of landslide conditions (unsafe conditions) accelerometer unstable output signal or a signal that is displayed varies, meaning that switching between reference signal followed by the signal amplitude changes very clearly visible. This is caused because the sensor recitations are unstable. 236 Figure 7. Accelerometer data during 4. Conclusion After carrying out this research it can be concluded as follows: 1. MMA73561L accelerometer device can be used for the detection of landslides in unstable landslides areas. 2. Maximum distance of the accelerometer data communication is 100 meter.

5 7-03 Accelerometer Data Transmission Based On Wireless Sensor Network 3. The weakness of this system is the usage of power, especially if applied in the field will bring some problems, because it should be continuously used. 5. Reference 1. Afif. 3 Desember Cara Setting Konfigurasi Xbee. ( 1/12/03/cara-setting-konfigurasi-x-bee, diakses agustus ATMELCorporationDatasheet ATMEGA bit AVR Microcontroller. ( pdf/view/164169/atmel/atmega85 35.htmldiakses januari Digi Internasional Data sheet XBee/XBee-PRO RF Modules. (Online), ( Wireless/Zigbee/XBee/Datasheet.pdf, diakses januari Palindung, Maryono dan Marty Matasik Peningkatan Jarak Jangkauan Jaringan Sensor Menggunakan Topologi tree pada frekuensi 2,3 GHz - 2,4 GHz. Makassar: Universitas Hasanuddin. 8.Riku. 21 September Wireless Sensor Network (WSN), ( ifile.it/wireless Sensor Networks (WSN).Riiku's Blog.htm, diakses Oktober Sampeallang, Herianto dan John T.P Perancangan dan Implementasi Jaringan Sensor (Sensor Network) Pada Frekuensi 2.3GHz 2.4GHz. Makassar : Universitas Hasanuddin. 10. Wahyono, Bagus Sistem Deteksi Gempa Bumi Berbasis Wireless Sensor Network. Surabaya: Institut Tegnologi Sepuluh November. 4.Febriani, Evi Arida Perancangan Elektrokardiograf (EKG) Berbasis PC untuk Sistem Telemedika. ( /TA-Yang-Sebetulnya, diakses mei Freescale. MMA7361L ±1.5g, ±6g Three AxisLow-gMicromachined Accelerometer. ( t- pdf/pdf/246143/freescale/mma7 361L.html, di akses juli Halim, Aplikasi Sensor Akselerometer Untuk Rancangbangun Sistem Peringatan Dini Tanah Longsor. Yogyakarta : Universitas Gadjah Mada, ( /7/Tanah-Longsor-Landslide, diakses Mei

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