Bera, R

Bhattacharya, S

Sen, A K

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Indian i  Pt^s. 75B (3), 245-246 (2001)U P  Ban mtemational journalDevelopment of a collision avoidance system at infrared wavelengthR Bera*, S Bhattacharya and A K SenInstituteofRadiophysicsandHlectronics, University of CalcuUa, 92. A V C Road, KolkoUi-700 009. Indiaand M DanEngineering Institute for Junior Executive, Dalalpukur, Howrah. West Bengal, India E-nMiil r_bera@hotmail.comAbstract To avoid collision of two moving systems, a collision avoidance system was developed using Infrared digital coded communication sysicm rhe Transmitter power of the Infrared source is adjusted so that the communication will be possible at a distance between the moving systems at which colli.sion avoidance is requiredkeywords Collision Avoidance system, digital code generator (ROM), infrared LEI) driver PAC S No. 07.57 Kp1. Introduction1 wo objects approaching towards each other often encounter mutual head-on collision creating disaster. To avoid such collisions an infra red (IR) automatic collision avoidance system has been developed by the millimetre wave group atthe Institute of Radio Physics and Electronics, C. U. [1], Actually, this is a remote controlled transceiver system which stops the object before accident after giving an alarmThe transmitter sends a signal and the transmitted power IS adjusted so that after a certain distance the detector cannot detect the signal level. This distance is adjusted up to the safely region. So initially when the objects are at safe distances, there is no communication. Now if the two objects enter into the danger zone, the receiver detects the signal, ihere is communication and immediately the power is cut off.-■ Experimental setupmain components of the transmitter are a digital code generator (ROM) and an IR LED driver (Figure 1). A ROM IS the fundamental block of the transmitter. Different codes are stored at different address location of thisROM. The ROM is triggered by a crystal oscillator at 455 kHz. By proper hardware connection, a particular address location of the ROM is chosen.CRYSTAL Trigger ^ ROM Code ^ LEDOSCILLATOR w DRIVERModulated IR RadiationI e'lponding AuthorFigure 1. Block diagram of the transmittaSo when the crystal oscillator triggers the ROM, required twelve bit digital code will be obtained at the output of ROM. This digital code is then fed to a current driver. This twelve bit digital coded electrical signal is converted to digital code modulated Infra red radiation by using an LED at the output. Finally, this amplitude modulated IR radiation is transmitted.The fundamental block of the receiver is a microprocessor- based decoder (Figure 2). The receiver mainly consists of an IR sensor; a microprocessor based decoder chip, an EEPROM chip, control circuits and a relay driver circuit. When two objects enter within the danger zone initiating the probability of collision, the modulated IR radiation from the transmitter is received by the receiver.At first, the IR sensor detects the signal. The signal is then amplified and processed by the pulse processor to get the© 2001 I ACS246 R Bera, S Bhattacharya, A K Sen and M DanTTL level. This signal is then fed to the microprocessor based intelligent decoder. When the desired code is received, the output of the intelligent receiver is then used to drive a replay, which finally stops the moving object by disconnectingIKDetectorI’rcAmpPulseProccssurlCircuilInilialiSHtionMicroprocessor Based DecoderI,ogic Module lo Avoid l.atchingFimire 2. Block diagram of the ReceiverRelayDrivertheir power supply. For initial data loading from the EEPRom a logic module for initialisation is added to the main circuit Also to avoid the latching of the decoder, another logic module is attached.To avoid the congested low frequency part, IR frequenev is used in the system, which also provides large bandwidth and narrow beam-width. The coded communication system provides a complete secured communication as the intelligent receiver responds to a particular code only and will not be affected by any other stray signal. Other beneficial features of the system are smaller size, portability and lower cost (2|References[I] Technical know-how document on "Collision avoidance at infrared wavelength" (project sponsored by TISCO) (19 (^j)12] An Infrared Digital Communication Link with Transmitter IJra/n Expander and Receiving Telescope fo r  Computer CommimicaUon S Bhattacharyya, M Dan, R Bera, A Maitra, A K Sen CODFX . ^98 (Science city, Calcutta, January) (1998)

Development of a Collision Avoidance System at Infrared Wavelength

http://arxiv.iacs.res.in:8080/jspui/bitstream/10821/6312/1/Development%20of%20A%20Collision%20Avoidance%20System_R%20Bera.pdf

Development of a Collision Avoidance System at Infrared Wavelength

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