What is this device suitable for?

Telemetry system is suitable for applications requiring automatic data measurement and transmission with data display and access through web sites. Suitable locations are areas with human supervision to prevent the loss or stolen of device and its components. Other requirements include electricity and mobile phone signal. However, if one of the requirements is missing, the system can still be adjusted. Any type of sensors can be connected but the data accuracy and effectiveness depends on the quality and sensitivity of sensors.

The telemetry system showcase

In 2004, the mobile telemetry system was setup and tested at different RID sites such as Petchaburi, Pranburi, Chao Phraya, Chantaburi, and Ping river basins. The requirements are  automatic real-time transmission of rainfall and stream water level data. At that time, those sites did not have any telemetry system. Problems arise during the trial usage period led to significant improvement of the telemeters and resulted in learning experiences.

One of the best success cases is the installation of telemetry system to send hourly rainfall data from Rayong province as a part of efforts to solve severe drought problem. In 2005, 13 mobile telemeters were installed in a total of 3 days or 3 hours per site. Data was transmitted immediately after installation. Therefore, rainfall situation was observed quickly and systematically. Data was archived for later assessment and warning messages were sent as short messaging service (SMS) via mobile phone.

What is mobile telemetry system?

Telemeter is a device that can measure physical, chemical or biological properties, then send the measurements to the set destination based on specified conditions. Examples of measured parameters are temperature, relative humidity, pH, dissolved oxygen level, or even a photo or information arising from the operation itself, such as work status.

 

Telemetry system is designed to be compact, easy-installed in little time, and portable.

 

The telemeter prototype from Japan – Field Server

The development of the telemetry system was based on data collections and long-range data transmission using Japanese “Field Server” developed by the National Agriculture and Food Research Organization (NARO) in Japan. We need to understand Japanese communication infrastructure in order to appreciate why this device is called “Field Server”.

 

Japan is one of the world’s leaders in information and communication technology (ICT). At that time, one of the famous communication services was a Wi-Fi or Wireless LAN which allows wireless internet connections of different devices besides computers, such as mobile phones or other devices. The advantage is Wi-Fi is commonly used as standard protocol all around the world, devices can connect to the internet directly, and direct communication with devices is done via IP-address system. Wi-Fi had been commonly used all over Japan and also South Korea. For Thailand, the Wi-Fi was initially developed by True Move. Therefore, this Japanese device connected to Wi-Fi can perform like a computer connected to internet. Sound, images, and videos can be transmitted. Therefore, it is regarded to as an outdoor “Field Server”. Besides having sensors for measurements and data transmission, VDO cameras can be attached to shoot photos and send VDOs via internet. The users with internet access can view the data and communicate with the Field Server from anywhere in the world.

 

The development of telemetry system in Thailand

In 2003, the “Field Server” was introduced by National Agriculture and Food Research Organization (NARO), Japan, in the Asia Pacific Advanced Network (APAN) conference. The participants from others countries were interested in this equipment because it was small, portable and easy to install, and had a low cost.

 

The National Electronics and Computer Technology Center (NECTEC), Thailand, had adapted this technology concept for appropriate utilization in Thailand. However at that time, Wi-Fi data communications had not yet been available everywhere for the whole country. Typical telemetry system in the market used wireless data communication packages - VHF or UHF which had limited frequency ranges. Therefore, NECTEC had selected the GPRS (General Packet Radio Service) as a communication method because it was uncomplicated and was a standard protocol for wireless data communication thru mobile network. After that, mobile service providers expanded their coverage to cover most areas of the country and did not pose restrictions in the connection. Advanced Info Service (AIS) and Total Access Communication (DTAC) are major mobile network providers and they performed regular maintenances of the service. Nevertheless, some weaknesses of the mobile applications were that the data could not be transferred in off-network areas. Thus, in those areas, applying an alternative wireless data communication and extending of network stations should be performed.

 

Mobile telemetry system is a project that adapted the “Field Server” technology, for appropriate applications in Thailand. NECTEC started to work on researches, to develop and test this telemetry system, and these duties were transferred to the Hydro and Agro Informatics Institute (HAII). Further development in sensors, network, and communication resulted in the telemetry system suitable for usage in Thailand. This telemetry system was installed in test sites to supplement the work performed by SCADA telemetry system and was called “Mobile telemetry system” because of its compact size and portability. This truly is the system developed by Thai people and has been used since then for various applications suitable for the Thai country.

 

 

How does telemetry system work?

Mobile telemetry system has simple workflow and focus on the use of standard interfaces that are easy to understand and be applied. A telemeter is divided into three parts according to how the device works.

 

1. Measurement Sensor: It measures a physical quantity and provides signals in standard format of 0-5 V or 4-20 mA. Presently, manufacturers come up with a variety of sensor probes, depending on the applications. For telemetry system, all types of sensors with the above standard can be installed to our telemeters. Examples include temperature, relative humidity, air pressure, solar radiation, and stream water level probes. The resolution and the accuracy depend on the specification by manufacturers. As a rule of thumb, select the sensor probe that is not too costly and provides sufficient accuracy for use in general. In the application requiring high precision, the sensor probe can be replaced with a high resolution one. In addition, rain sensor using tipping bucket mechanism was also developed for rainfall measurements.

 

1. Controller: It is a device controlling the operation and data transmission. This device is the heart of the operation, with the microcontroller to control all functions of the operation. It was developed and programmed in-house at HAII, so it can be customized and modified when needed. Timing for measurement recording and system operation can be set and data is transmitted in the standard format RS232 to the data transfer device via GPRS system. Data can also be recorded in the controller flash memory, so the user can remove the memory to extract data at a later time. The user set the time interval for parameter measurements and the recordings will occur at every time step, such as 10-minute interval, hourly, or daily, followed by instant data transmission in a text format to the server for processing and automatic display with time stamps. The user can also connect a computer directly to the controller to get the readings, without the need to use special program, and can export data to use in the form of tables or graphs using Excel program.

 

1. Power supply with anti-surge equipment: This system uses 12V and can utilize various electrical power sources such as the use of transformer to convert from 220V home electricity to 12V DC or the use of car battery. Future development plan includes reducing power use such that small solar panel can be applied as the power source. Due to the small size, this device can be contained in a water-proof plastic box and be installed outdoor or can be installed indoor for easy care and maintenance.

 

In actual usage, the telemetry system sends data via GPRS system to the server with proper data socket, and data is filtered before being stored in the database. Data display is available through web sites or a WAP browser for mobile phones. The user can choose to view data based on location or time period, in the format of numbers, graphs, or tables, as well as viewing operation status. Data can also be visualized in a geographic information system via internet.

 

 

Technical information

• PIC 18F4658 microcontroller and real time clock circuit with batteries are major part of the whole system, controlling all processes.

• 8 ports with 10 bit of analog to digital circuit can be extended up to 12 bit at unlimited ports.

• A single port is used for connecting with rainfall sensor circuit.

• A single port is used for connecting with temperature and humidity sensor circuit.

• 8 input-output ports for TTL 5V controller can be extended up to unlimited ports.

• A single RS-232 port with 9 pins type is used for connecting and commanding via text from a computer to the telemetry system.

• A single USB port is connected with a flash memory to collect data.

• A GPRS modem is used for transmitting the collected data via GPRS mobile service which is available in both AIS and DTAC system. By adjusting an antenna, it can transfer longer distance signals.

• 9 – 30 V DC can be used for this telemetry system, appropriately including a single connector of 12 V DC. with 500 mA. available for usage.

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What is this device suitable for?

Telemetry system is suitable for applications requiring automatic data measurement and transmission with data display and access through web sites. Suitable locations are areas with human supervision to prevent the loss or stolen of device and its components. Other requirements include electricity and mobile phone signal. However, if one of the requirements is missing, the system can still be adjusted. Any type of sensors can be connected but the data accuracy and effectiveness depends on the quality and sensitivity of sensors.

 

The telemetry system showcase

In 2004, the mobile telemetry system was setup and tested at different RID sites such as Petchaburi, Pranburi, Chao Phraya, Chantaburi, and Ping river basins. The requirements are automatic real-time transmission of rainfall and stream water level data. At that time, those sites did not have any telemetry system. Problems arise during the trial usage period led to significant improvement of the telemeters and resulted in learning experiences.

 

One of the best success cases is the installation of telemetry system to send hourly rainfall data from Rayong province as a part of efforts to solve severe drought problem. In 2005, 13 mobile telemeters were installed in a total of 3 days or 3 hours per site. Data was transmitted immediately after installation. Therefore, rainfall situation was observed quickly and systematically. Data was archived for later assessment and warning messages were sent as short messaging service (SMS) via mobile phone.

 

 

Continual improvements

Nowadays, the telemetry system has been developed to achieve future goals by applying new technologies for further applications such as for 2-way communication to remotely control devices or equipment at the installation sites. Other areas of improvement are energy conservation by the use of solar cell, increasing efficiency of measurement sensors, enhancing signals and extending number of sensor channels. In order to apply for various proposes in Thailand, the telemetry system has been researched, developed and produced, proudly by Thai people. The goal is to have accurate and reliable real-time data for water resource management.

 

Telemetry system operation chart