The one wich me n my batch r doin is 'Cellphone operated Robot'
Here is the overview
STEP 1 - PROJECT OVERVIEW
In this project the robot, is controlled by a mobile phone that makes call to the mobile phone attached to the robot 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) robot receives this DTMF tone with the help of phone stacked in the robot
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 robot acts as a remote. So this simple robotic project does not require the construction ofreceiver and transmitter units.
DTMF signaling is used for telephone signaling over the line in the voice frequency band to the call switching center. The version of DTMF used for telephone dialing is known as touch tone.
DTMF assigns a specific frequency (consisting of two separate tones) to each key s that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is the direct al-gebric submission, in real time of the amplitudes of two sine(cosine) waves of different frequencies, i.e. ,pressing 5 will send a tone made by adding 1336hz and 770hz to the other end of the mobile. The tones and assignments in a dtmf system.
STEP 2 - Circuit Description
The important components of this robot are 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 decodeall the sixteen DTMF tone pairs in to a four bit code output. The built -in dila tone regection circuit eliminated the need for pre- filtering. When the input signal given at pin2 (IN-) single ended input configuration is recognized to be effective, the correct four bit decode signal of the DTMF tone is transferred to Q1 (pin11) through Q4(pin14) outputs.
The atmega 16 is a low power, 8 bit, cmos microcontroller based on the AVR enhanced RISC architecture. It provides the following feature: 16kb of in system programmable flash memory with read write capabilities, 512bytes of EEPROM, 1KB SRAM, 32 general purpose input/output lines. 32 general purpose working registers. All the 32 registers are directly connected to the arithmetic logic unit, allowing two independent registers to be accessed in one signal instruction executed in one clock cycle. The resulting architecture is more code efficient. Outputs from port pins PD0 through PD3 and PD7 of the microcontroller are fed to inputs IN1 through IN4 and enable pins (EN1 and EN2) of motor driver L293d respectively, to drive geared motors. Switch S1 is used for manual reset.
STEP 3 - Software description (the hex code)
the Avr microcontroller is programmed using WIN AVR
STEP 4 - Working
In order to control the robot, you have to make a call to the cellphone attached to the robot from any phone.
now the phone is picked by the phone on the robot through autoanswer mode(which is in the phn, just enable it).
now when you press 2 the robot will move forward
when you press 4 the robot will move left
when you press 8 the robot will move backwards
when you press 6 the robot will move right
when you press 5 the robot will stop.
STEP 5 - Construction :Arrow:
For constructing this robot, you require these components
" MT8870 DTMF DECODER - 1
" Atmega 16 microcontroller - 1
" L293d motor driver ic - 1
" Cd7004 not gate ic - 1
" 1n4007 diode - 1
" 100k resistances - 2
" 10 k resistances - 5
" 330 k resistances - 1
" 0.47mf capacitors - 1
" 0.1mf capacitors - 1
" 22pf capacitors - 4
" 3.57mhz crystal - 1
" 12mhz crystal - 1
" Push to on switch - 1
" 2 geared motors (6v, 50 rpm) - 2 (4 for four wheel drive)
" Battery 6v - 1
* wheels - 4
* cellphone - 2 (one urs and one can be ur friends)
* handsfree - 1 (for the phone on the rover)
You have to place a cellphone on the rover. The cellphone is connected to the rover through a handsfree. construct the rover in the shape which is given below.
Follow the steps and u r done.