This research is aimed to establish the small wireless sensor network under the real environment. The objectives this research is aimed to study the data transmission and evaluate the data transmission performance of RPL protocol in wireless sensor network. Four nodes of wireless sensor network have been installation and transmissions between nodes in single-hop and multi-hop have been simulation for testing and analyzing data from the network following the transmission performance index. The research found that the number of hop and building environment are the principle factor to the performance of RPL protocol this might be the major limit to implement the RPL protocol in wireless sensor network

The objective of this research was to study environment changes in orchards by using wireless sensor network and spatial data interpolation technique. The study was conducted by distributing several client sensors into the two study areas for recoding temperature himudity and light internsity. These data are send to a server using 433 MHz radio signal. The results from the first study area in Thachang District shew that the light intensities were significantly changed during 6:00-6:59 11:00-14:00 and 18:00-19:59. For the humidities they were significantly changed during 7:00-8:59 17:00-19:59 and 22:00-23:00 which were quite different from the changing of light intensity. Lastly the temperatures were mostly changed during 7:00-7:59 10:00-14:59 and 18:00-19:59 which were highly related to the changes of light intensity. For the second study area in Angkhiri District light intensities were significantly changed during 7:00-7:59 11:00-14:00 and 18:00-19:59 while the changing durations for the humidities were 9:00-9:59 12:00-15:00 and 17:00-19:59. Very similarly to the light intensity the temperatures were changed during 8:00-8:59 11:00-14:59 and 15:00-17:59. For the communiation distances the maximum distance for transfering data in an open area was 100 meter and 25 meters with obstables.

งานวิจัยนี้นำเสนอการสร้างตัวตรวจจับไร้สาย (Wireless sensor) แบบอัตราต่ำ (Low rate) ที่มีขนาดเล็กราคาไม่แพง ภายในมีส่วนประมวลผล ส่วนติดต่อสื่อสารและส่วนตรวจจับ (Sensing Device) เพื่อใช้ในระบบการเฝ้าสังเกต และตรวจจับการเกิดน้ำท่วม โดยนำมาใช้กับเครือข่ายตรวจจับไร้สาย (Wireless sensor networks : WSN) ข่อจำกัดของตัวตรวจจับอยู่ที่พลังงาน ระยะทางในการติดต่อสื่อสาร และความสามารถในการประมวลผล แต่จะทำงานร่วมกันเป็นเครือข่ายขนาดใหญ่ เพื่อตรวจจับเหตุการณ์ที่ต้องการในพื้นที่ขนาดใหญ่ ที่มีการเข้าถึงลำบากหรือต้องเสี่ยงภัย มีการรับส่งข้อมูลจากจุดตรวจจับ (Sensor Nods) แต่ละจุดรวบรวมและส่งต่อข้อมูลเพื่อนำไปประมวลผลหรือใช้ในการเตือนภัย ในขั้นต้นของการทดลองจะสร้างโนด และหาเปอร์เซ็นต์ของการรับส่งระหว่างโนดหลัก และโนดย่อย

This research presents the development of a low rate wireless sensor. Wireless sensor networks are cheap and comprised of a small fully autonomous processing communication and sensing devices. The purpose of this study is to develop the system for monitoring and flood warning. They will work with wireless sensor network (WSN) system. WSN has been restricted power supply communication distance and low computing power. But they will work with network in vast area send and receive raw data from each sensor node. It has the ability to cooperatively collect data and retransmit in order to process or alert. The first step of the experiment is creating main node and sub node in flooding area and finds transmission of data between them.

This paper presents a low cost wireless sensor network system which is developed to be an alerting system for relatives or caregivers when the elder is immobile for a long period. The alerting signal is sent via the Internet link and a mobile phone. Remote transducers capture input signal from the mobility subject. If the target subject has immobilized behavior for long period which is analyzed abnormal condition the system will send the alerting messages to a selected mobile phone or Internet link. After detection of motionless elder from the set–point periods the system immediately distributes messages via SMS on the mobile network and a server to warn a relative or a caregiver with the image option to send. The sensor modules have ease-ofinstallation with coverage area nearly 3 square meters 80 % of detection level suitable for a small room and a bathroom