16-11-2012, 12:20 PM
PROJECT REPORT ON LANDLINE/CELLPHONE OPERATED LAND ROVER
CELLPHONE OPERATED.doc (Size: 905.5 KB / Downloads: 30)
Introduction
What is a Mobile controlled DTMF ?
DTMF Mobile is a machine that can be
controlled with a mobile . In this project, the motro is controlled by a mobile phone that makes a call to the mobile phone attached to the motor. In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call. This tone is called "Dual Tone Multiple-Frequency" (DTMF) tone. The motor perceives this DTMF tone with the help of the phone stacked on the motor. The received tone is processed by the microcontroller with the help of DTMF decoder. The microcontroller then transmits the signal to the motor driver ICs to operate the motors & our motor starts moving
Why build a DTMF MOTOR?
Conventionally, Wireless-controlled motors use rf circuits,
which have the drawbacks of limited working range, limited frequency range and the limited control. Use of a mobile phone for motoric control can overcome these limitations. It provides the advantage of robust control, working range as large as the coverage area of the service provider, no interference with other controllers and up to twelve controlles.
Although the appearance and the capabilities of motors vary vastly, all motors share the feature of a mechanical, movable structure under some form of control. The Control
of motor involves three distinct phases: perception, processing and action. Generally, the preceptors are sensors mounted on the motor , processing is done by the on-board microcontroller or processor, and the task is perfomed using motors or with some other actuators.
POJECT OVERVIEW:
In this project the motor, is controlled by a mobile phone that makes call to the mobile phone attached to the motor in the course of the call, if any button is pressed control corresponding to the button pressed is heard at the other end of the call. This tone is called dual tone multi frequency tome (DTMF) motor receives this DTMF tone with the help of phone stacked in the motor
The received tone is processed by the atmega16 microcontroller with the help of DTMF decoder MT8870 the decoder decodes the DTMF tone in to its equivalent binary digit and this binary number is send to the microcontroller, the microcontroller is preprogrammed to take a decision for any give input and outputs its decision to motor drivers in order to drive the motors for forward or backward motion or a turn. The mobile that makes a call to the mobile phone stacked in the motor acts as a
remote. So this simple motoric project does not require the construction ofreceiver and transmitter units.
DTMF Decoder
The MT-8870 is a DTMF Receiver that integrates both band split filter and
decoder functions into a single 18-pin DIP or SOIC package. It is manufactured using CMOS process technology. The MT-8870 offers low power consumption (35 mW max) and precise data handling.
ATMEL89C52
Description:
The AT89C52 is a low-power, high-performance CMOS 8-bit microcomputer
with 8K bytes of Flash programmable and erasable read only memory (PEROM).
The deviceis manufactured using Atmel‟s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pinout.
The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C52 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
MEMORY SPACE ALLOCATION:
The 8051 has three very general types of memory. To effectively program the 8051 it is necessary to have a basic understanding of these memory types. The memory types are illustrated in the following graphic. They are: On-Chip Memory, External Code Memory, and External RAM.
Onchip ROM
The 89C51 has a 4K bytes of on-chip ROM. This 4K bytes ROM memory has memory addresses of 0000 to 0FFFh. Program addresses higher than 0FFFh,
which exceed the internal ROM capacity will cause the microcontroller to automatically fetch code bytes from external memory. Code bytes can also be fetched exclusively from an external memory, addresses 0000h to FFh, by connecting the external access pin to ground. The program counter doesn‟t care where the code is:
the circuit designer decides whether the code is found totally in internal ROM, totally in external ROM or in a combination of internal and external ROM.
External RAM
External RAM is RAM memory that resides off-chip. This is often in the form of standard static RAM or flash refers to any memory (Code, RAM, or other) that physically exists on the microcontroller itself. On-chip memory can be of several types, but we'll get into that shortly.
External RAM As an obvious opposite of Internal RAM, the 8051 also supports what is called External RAM. As the name suggests, External RAM is any random access memory which is found off-chip. Since the memory is off-chip it is not as flexible in terms of accessing, and is also slower. For example, to increment an Internal RAM location by 1 requires only 1 instruction and 1 instruction cycle. To increment a 1- byte value stored in External RAM requires 4 instructions and 7 instruction cycles. In this case, external memory is 7 times slower!
Code Memory
Code memory is the memory that holds the actual 8051 program that is to be run. This memory is limited to 64K and comes in many shapes and sizes: Code memory may be found on-chip, either burned into the microcontroller as ROM or EPROM. Code may also be stored completely off-chip in an external ROM or, more commonly, an external EPROM. Flash RAM is also another popular method of storing a program. Various combinations of these memory types may also be used-- that is to say, it is possible to have 4K of code memory on-chip and 64k of code memory off-chip in an EPROM.
Program Counter and Data Pointer
The program counter is a 16- bit register and it points
to the address of the next instruction to be executed. As the CPU fetches op-code from the program ROM, the program counter is incremented to point to the next
instruction. Since the PC is 16 bit wide, it can access program addresses 0000 to FFH, a total of 64K bytes of code. However, not all the members of the 8051 have the entire 64K bytes of on-chip ROM installed.
The DPTR register is made up of two 8-bit registers, DPH and DPL, which are used to furnish memory addresses for internal and external
data access. The DPTR is under the control of program instructions and can be
specified by its name, DPTR. DPTR does not have a single internal address, DPH and
DPL are assigned an address each.
Flag bits and the PSW Register
Like any other microprocessor, the 8051 have a flag
register to indicate arithmetic conditions such as the carry bit. The flag register in the
8051 is called the program status word (PSW) register.
The program status word (PSW) register is an 8-bit register. It is also referred as the flag register. Although the PSW register is 8-bit wide, only 6 bits of it are used by the microcontroller. The two unused bits are user definable flags. Four of the flags are conditional flags, meaning they indicate some conditions that resulted