Summary of CELLPHONE OPERATED LAND ROVER
Reading makes man ready, writing makes man steady, but practice makes man perfect. This project documents a cellphone-operated land rover that uses DTMF tones from a caller to control motion. A phone on the rover receives touch-tone signals, an MT8870 DTMF decoder converts tones to 4-bit codes, and an ATmega16 microcontroller interprets codes to drive an L293D motor driver, which powers two DC geared motors for forward, reverse, and turns. The system uses headset audio input, auto-answering phone mode, and includes reset and control logic for practical robotics implementation and testing.
Parts used in the Cellphone Operated Land Rover:
- Mobile phone (transmitter) used by the operator
- Mobile phone (mounted on rover) for receiving calls and DTMF tones
- Headset/cable to feed audio from rover phone to circuit
- MT8870 DTMF decoder IC
- ATmega16 microcontroller
- L293D motor driver IC
- Two geared DC motors
- Power supply/battery for motors and electronics
- Reset switch S1
- Interconnecting wiring and PCB or protoboard
I know the general rule of world that “reading makes man ready,writing makes man everyday but practice makes man perfect.” Only theoretical knowledge is not enough for an E.C (Electronics and communication engineering)student. A project is one of the subjects in which we have to develop hardware with software, where we not theoretically analyze the system but also design software and implement the same into the IC. The final phase is to test the functionally of project action. From this subject student can get opportunity of real implementation of theoretically concept of “robotics” and “software in atmega 16” in the practical filed. Here programing, system testing and quality checking and control This documentation the report of mobile operated land rover from this documentation we can understand the hardware and software engineering concept can be implemented to a real problem.
PROJECT OVERVIEW
The important components of this robot are a DTMF decoder, microcontroller and motor driver.An MT8870 series DTMF decoder is used here. All types of the MT8870 series use digital counting techniques to detect and decode all the 16 DTMF tone pairs into a 4-bit code output.The built-in dial tone rejection circuit eliminates the need of pre-filtering. when the input signal given at pin 2(IN-) in single-ended input configuration is recognized to be effective, the correct-bit decode signal of the DTMF tone is transferred to (pin11) through (pin14) outputs.The pin11 to pin14 of DTMF decoder are connected to the pins of microcontroller (pa0 to pa3).The ATmega16 is a low power, 8-bit CMOS microcontroller based on the AVR enhanced RISC architecture. it provides the following features: 16kb of in-system programmable flash program memory with read-while-write capabilities, 512 bytes of eeprom, 1kb SRAM, 32(IO) lines.outputs from port pins PD0 through PD3 and PD7 of the microcontroller are fed to the inputsIN1 through IN4 and enable pins (EN1 and EN2) of motor driver L293D IC, respectively to drive two geared dc motors. Switch S1 is used for manual reset. The microcontroller output is not sufficient to drive the dc motors, so Current drivers are required for motor rotation.The L293D is a quad, high-current, half-h driver designed to provide bidirectional drive currents of upto600mA at voltages from 4.5V to 36V. It makes it easier to drive the dc motors. The L293D consists of four drivers. Pins IN1 through IN4 and OUT1 through OUT4 are the input and output pins respectively, of driver 1 through driver 4. Drivers 1 and 2, and driver 3 and 4 are enabled by enable pin 1(EN1) and pin 9 (EN2), respectively. When enable input EN1 (pin1) is high, drivers 1 and 2 are enabled and the outputs corresponding to their inputs are active.
WORKING :
For more detail: CELLPHONE OPERATED LAND ROVER
- How does the robot receive commands from a mobile phone?
The operator calls the phone mounted on the robot and presses keys that generate DTMF tones received by the rover phone via the headset input. - Can the system work without building RF transmitter and receiver circuits?
Yes, the project uses existing mobile phones and DTMF over a call, so no separate transmitter or receiver units are required. - What decodes the DTMF tones into binary codes?
An MT8870 series DTMF decoder detects and decodes the 16 DTMF tone pairs into a 4-bit code output. - What microcontroller is used to process the decoded signals?
The ATmega16 microcontroller processes the 4-bit codes from the DTMF decoder and decides motor actions. - How are the DC motors driven since microcontroller outputs are insufficient?
The L293D motor driver IC provides the required current drive to the two geared DC motors under control of the microcontroller outputs. - How does the rover answer incoming calls?
The rover phone is kept in auto answer mode or the call is manually accepted and switched to hands-free to feed audio to the circuit. - Which microcontroller port pins connect to the DTMF decoder outputs?
The DTMF decoder outputs on pins 11 to 14 are connected to the microcontroller port A pins PA0 to PA3. - Which outputs of the microcontroller control the motor driver inputs?
The microcontroller outputs from PD0 through PD3 and PD7 are fed to IN1 through IN4 and the enable pins EN1 and EN2 of the L293D motor driver.
