The main aim of this project is to design a Traffic light controller using 8085 microprocessor, interfacing with peripheral device 8085, and program implementing the process.IntroductionThe 8085 Microprocessor is a popular Microprocessor used in Industries for various applications. Such as traffic light control, temperature control, stepper motor control, etc. In this project, the traffic lights are interfaced to Microprocessor system through buffer and ports of programmable peripheral Interface 8255. So the traffic lights can be automatically switched ON/OFF in desired sequence. The Interface board has been designed to work with parallel port of Microprocessor system.The hardware of the system consists of two parts. The first part is Microprocessor based system with 8085. Microprocessor as CPU and the peripheral devices like EPROM, RAM, Keyboard & Display Controller 8279, Programmable as Peripheral Interface 8255, 26 pin parallel port connector, 21 keys Hexa key pad and six number of seven segment LED's.The second part is the traffic light controller interface board, which consist of 36 LED's in which 20 LED's are used for vehicle traffic and they are connected to 20 port lines of 8255 through Buffer. Remaining LED's are used for pedestrian traffic. The traffic light interface board is connected to Main board using 26 core flat cables to 26-pin Port connector. The LED's can be switched ON/OFF in the specified sequence by the Microprocessor. Get Help With Your EssayIf you need assistance with writing your essay, our professional essay writing service is here to help!
The normal function of traffic lights requires sophisticated control and coordination to ensure that traffic moves as smoothly and safely as possible and that pedestrians are protected when they cross the roads. A variety of different control systems are used to accomplish this, ranging from simple clockwork mechanisms to sophisticated computerized control and coordination systems that self-adjust to minimize delay to people using the road.Traffic Controller SystemsA traffic signal is typically controlled by a controller inside a cabinet mounted on a concrete pad. Although some electro-mechanical controllers are still in use (New York City still has 4,800), modern traffic controllers are solid state. The cabinet typically contains a power panel, to distribute electrical power in the cabinet; a detector interface panel, to connect to loop detectors and other detectors; detector amplifiers; the controller itself; a conflict monitor unit; flash transfer relays; a police panel, to allow the police to disable the signal; and other components.Fixed Time ControlThe simplest control system uses a timer (fixed-time): each phase of the signal lasts for a specific duration before the next phase occurs; this pattern repeats itself regardless of traffic. Many older traffic light installations still use these, and timer-based signals are effective in one way grids where it is often possible to coordinate the traffic lights to the posted speed limit. They are however disadvantageous when the signal timing of an intersection would profit from being adapted to the dominant flows changing over the time of the day.Dynamic ControlDynamic, or actuated, signals are programmed to adjust their timing and phasing to meet changing traffic conditions. The system adjusts signal phasing and timing to minimize the delay of people going through the intersection. It is also commonplace to alter the control strategy of a traffic light based on the time of day and day of the week, or for other special circumstances such as a major event causing unusual demand at an intersection.The controller uses input from detectors, which are sensors that inform the controller processor whether vehicles or other road users are present, to adjust signal timing and phasing within the limits set by the controllersprogramming. It can give more time to an intersection approach that is experiencing heavy traffic, or shorten or even skip a phase that has little or no traffic waiting for a green light. Detectors can be grouped into three classes: in-pavement detectors, non-intrusive detectors, and detection for non-motorized road users.Working ProgramDesign of a microprocessor system to control traffic lights. The traffic should be controlled in the following manner.1) Allow traffic from W to E and E to W transition for 20 seconds. 2) Give transition period of 5 seconds (Yellow bulbs ON) 3) Allow traffic from N to 5 and 5 to N for 20 seconds 4) Give transition period of 5 seconds (Yellow bulbs ON) 5) Repeat the process.Source Program:MVI A, 80H: Initialize 8255, port A and port BOUT 83H (CR): in output modeSTART: MVI A, 09HOUT 80H (PA): Send data on PA to glow R1 and R2MVI A, 24HOUT 81H (PB): Send data on PB to glow G3 and G4MVI C, 28H: Load multiplier count (40ıο) for delayCALL DELAY: Call delay subroutineMVI A, 12HOUT (81H) PA: Send data on Port A to glow Y1 and Y2OUT (81H) PB: Send data on port B to glow Y3 and Y4MVI C, 0AH: Load multiplier count (10ıο) for delayCALL: DELAY: Call delay subroutineMVI A, 24HOUT (80H) PA: Send data on port A to glow G1 and G2MVI A, 09HOUT (81H) PB: Send data on port B to glow R3 and R4MVI C, 28H: Load multiplier count (40ıο) for delayCALL DELAY: Call delay subroutineMVI A, 12HOUT PA: Send data on port A to glow Y1 and Y2OUT PB: Send data on port B to glow Y3 and Y4MVI C, 0AH: Load multiplier count (10ıο) for delayCALL DELAY: Call delay subroutineJMP STARTDelay Subroutine:DELAY: LXI D, Count: Load count to give 0.5 sec delayBACK: DCX D: Decrement counterMOV A, DORA E: Check whether count is 0JNZ BACK: If not zero, repeatDCR C: Check if multiplier zero, otherwise repeatJNZ DELAYRET: Return to main programReferenceswww.rbainnovations.com/.../A%208085/H%20Traffic%20light%20controller-n.docwww.freshpatents.com/-dt20090702ptan20090167561.php -programs-for-8085-microprocessor.aspx -Light-Control.aspxU.S.Shah, Microprocessor and its applications, Tech- Max Pulications, Pune. Share this:FacebookFacebook logoTwitterTwitter logoRedditReddit logoLinkedInLinkedIn logoWhatsAppWhatsApp logo Cite This WorkTo export a reference to this article please select a referencing stye below:
Traffic Light Controller Using 8086 Microprocessor Pdf Free
We see here is a battery, a light bulb, a coil of wire around apiece of iron (yellow), and a switch. The coil of wire is aninductor. If we have read How Electromagnets Work, we will alsorecognize that the inductor is an electromagnet. If we were to takethe inductor out of this circuit, then what we have is a normalflashlight. We close the switch and the bulb lights up. With theinductor in the circuit as shown, the behavior is completelydifferent. The light bulb is a resistor (the resistance createsheat to make the filament in the bulb glow). The wire in the coilhas much lower resistance (it's just wire), so what you wouldexpect when you turn on the switch is for the bulb to glow verydimly. Most of the current should follow the low-resistance paththrough the loop. What happens instead is that when you close theswitch, the bulb burns brightly and then gets dimmer. When we openthe switch, the bulb burns very brightly and then quickly goes out.Microprocessor as traffic light control system: A traffic lightcontrol and information transmission device comprising: amicroprocessor located inside the traffic control box and tocontrol all the circuitries; a traffic light controller connectedto and controlled by said microprocessor to send out the stop, goand direction signals; an electronic display board connected to andcontrolled by said microprocessor to display characters, patternsand graphic images; a video camera connected to and controlled bysaid microprocessor to monitor the traffic flow; a compressioncircuitry connected to said microprocessor and said video camera,said compression circuitry compresses the image data captured bysaid video camera and sends the data to said microprocessor; an I/Ointerface connected to said microprocessor to receive, transmitdata and control signals; a traffic flow detector connected to saidI/O interface and gathering the traffic flow information; thetraffic flow information is input to said microprocessor; a DSLconnected to said I/O interface 6 and receiving, transmitting dataand control signals; a broadband network linking said
DSL and a central traffic control computer together, saidcentral traffic control computer sends out and receives the dataand controls signals to said microprocessor through said broadbandnetwork. Traffic light control system using 8086 microprocessor:Traffic light controller interface module is designed to simulatethe function of four way traffic light controller. Combinations ofred, amber and green LEDs are provided to indicate Halt, Wait andGo signals for vehicles. Combination of red and green LEDs areprovided for pedestrian crossing. 36 LEDs are arranged in the formof an intersection. A typical junction is represented on the PCBwith comprehensive legend printing. At the left corner of eachroad, a group of five LEDs (red, amber and 3 green) are arranged inthe form of a T-section to control the traffic of that road. Eachroad is named North (N), South(S), East (E) and West (W). LEDs L1,L10, L19 & L28 (Red) are for the stop signal for the vehicleson the road N, S, W, & E respectively. L2, L11, L20 & L29(Amber) indicates wait state for vehicles on the road N, S, W,& E respectively. L3, L4 & L5 (Green) are for left, straitand right turn for the vehicles on road S. similarly L12-L13-L14,L23-L22-L21 & L32-L31-L30 simulates same function for the roadsE, N, W respectively. A total of 16 LEDs (2 Red & 2 Green ateach road) are provided for pedestrian crossing. L7-L9.L16-L18,L25-L27 & L34-L36 (Green) when on allows pedestrians to crossand L6-L8, L15-L17, L24-L26 & L33-L35 (Red) when on alarms thepedestrians to wait. To minimize the hardware pedestrians indicatorLEDs (both red and green are connected to same port lines (PC4 toPC7) with red inverted. Red LEDs L10 & L28 are connected toport lines PC2 & PC3 while L1 & L19 are connected to linesPC0 & PC1 after inversion. All other LEDs (amber and green) areconnected to port A & B. WORKING:8255 is interfaced with 8086in I/O mapped I/O and all ports are output ports. The basicoperation of the interface is explained with the help of theenclosed program. The enclosed program assumes no entry of vehiclesfrom North to West, from road East to South. At the beginning ofthe program all red LEDs are switch ON, and all other LEDs areswitched OFF. Amber LED is switched ON before switching over toproceed state from Halt state. The sequence of traffic followed inthe program is given below. a) From road north to East From roadeast to north From road south to west From road west to south Fromroad west to north b) From road north to East From road south towest From road south to north From road south to east c) From roadnorth to south From road south to north Pedestrian crossing atroads west & east d) From road east to west From road west toeast Pedestrian crossing at roads north & south
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