{"id":2066,"date":"2011-03-23T11:31:44","date_gmt":"2011-03-23T10:31:44","guid":{"rendered":"http:\/\/www.gsm-modem.de\/M2M\/?p=2066"},"modified":"2011-06-05T09:10:22","modified_gmt":"2011-06-05T07:10:22","slug":"trailer-detection-active-rfid","status":"publish","type":"post","link":"http:\/\/www.gsm-modem.de\/M2M\/m2m-faq\/trailer-detection-active-rfid\/","title":{"rendered":"Why paying for complier, licence fee, property rights, antennas, schematics and code? Today: Trailer detection by active RFID"},"content":{"rendered":"

Reference design trailer detection for OBU One Board Unit by using active RFID<\/h2>\n

Description of the trailer detection by active RFID<\/h3>\n

At the trailer is a 2400 MHz transceiver working as active RFID tag and it transmits its unique ID each few seconds. By selecting the duty cycle the standby time of the battery will be interfered. Good performed well matched antennas will help to save the battery again. The wired link of the tag reader will be connected to the On Board Unit.<\/p>\n

\"active<\/a>

Active RFID by inexpensive 2400 MHz consumer technology<\/p><\/div>\n

The UART with its 9600 bit is symbolic and can be replaced to SPI. UART or SPI will be converted to CAN-bus. The CAN-bus is more robust and will be wired to to the On Board Unit (OBU) in the truck. RS485 instead of CAN-Bus is also an option. The cheapest concept will be to use the 8051 micro controller to control the GPRS module and the GPS module as well. The active RFID reader and the On Board Unit and active RFID reader will be one and the same. Anyhow, how to save further costs by designing an On Board Unit will be explained later at this blog.<\/p>\n

\"Trailer<\/a>

Trailer detection by active RFID<\/p><\/div>\n

This proposal is using commercial field approved consumer electronic by covering a wide temperature range of -40 to +85\u00c2\u00b0 C and with focus on ultra long operating time on battery. The supply voltage range of the semiconductors is from 1,9 to 3,6 Volt. The power consumption is so less that standard coin cell batteries can be used to reach years of operating. By the way, the power consumption of this system on chip is so less, that the self discharge of batteries is even higher. Selecting the consumer components helps with a very low price, too. The necessary further external parts are cheap as well. The antenna is gratis, because it is PCB track only. The used radio link protocol is licence free. There is no money to spend like with ZigBee or Bluetooth. The protocol is secure because it is using an AES128 encryption\/decryption and it is field approved with wireless mice, keyboards, remote controls and USB dongles.<\/p>\n

The evaluation kits for this application are inexpensive. The minimum are two ready to use 2400 MHz radio modules with ready to use radio link protocol and firmware. Within minutes you will get a working sample. Just plug the coin cell batteries to the 2400 MHz radio modules and code one module in mode active RFID and the other in mode \u00e2\u20ac\u0153toggling output pin\u00e2\u20ac\u009d and wire a LED. As long the 2400 MHz radio module coded as active RFID will be in the near of the receiving radio module the LED will flash. The next step will be to code the receiving 2400 MHz radio module as a transparent radio to UART link. The received unique ID of the active RFID beacon will be forwarded to the UART. The UART can be wired by USB or RS232 converter to your PC. If you use some kind of terminal software (e.g. Hyperterm on Windows), then you will see the unique ID of the active RFID tag on the screen. The further step is to replace the PC to Smart Phone, GSM\/GPS terminal or the Arduino based evaluation kit listed here.
\nhttp:\/\/www.gsm-modem.de\/M2M\/m2m-apps\/gsm-gprs-gps-shield-for-arduino-board-duemilanove-atmega328\/<\/a><\/p>\n

By using the Arduino based GSM\/GPS evaluation kit you have the most options and the big Arduino community in the background.<\/p>\n

Trailer detection by active RFID – student evaluation kit<\/h3>\n