Conventionally, Wireless-controlled robots use rf circuits, which have the drawbacks of limited working range, limited frequency range and the limited control. Use of a mobile phone for robotic 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 robots vary vastly, all robots share the feature of a mechanical, movable structure under some form of control. The Control of robot involves three distinct phases: perception, processing and action. Generally, the preceptors are sensors mounted on the robot , processing is done by the on-board microcontroller or processor, and the task is perfomed using motors or with some other actuators.
i want to make it clear, if you face any problem i am dere for you
, you can write comments or you can mail me at firstname.lastname@example.org
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 shown below
Step 2: Circuit Description
Figures shows the block diagram and cicuit diagram of the microcontroller- based robot. 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.
the notations are :
ic1 - mt8870
ic2 - atmega16
ic3 - l293d
ic4 - cd7004
r1,r2 - 100k resistances
r3 - 330k resistances
r4-r8 - 10k resistances
c1- 0.47 micro farat capacitor
c2,c3,c5,c6 - 22pfarat capacitor
c4 - 0.1micro farat capacitor
xtal1 - 3.57 mhz crytal
xtal2 - 12mhz crystal
s1 - push to on switch
m1,m2 - 6v 50rpm motor
Step 3: Software Description (the Hex Code)
the Avr microcontroller is programmed using WIN AVR
for beginners have a look at this instructable first
this is the way to pogram the avratmega 16
look at the pin diagram of atmega16 and then connect the pins acordingly (if u have any problem then feel free to write me)
i have attached the full code. The header file will be included automatically if u have installed the winavr in default location
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
" 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 frnds)
- handsfree - 1 (for the phn on the rover)
You can get these parts from any electronic store with ease
Step 6: To Connect the Hands Free With the Circuit
there are always two connections which come out of the phone,
these connections are
i'll prefer to use handsfree which have a straight jack (similar to the ones which we use in our ipods, but a thinner one)
the tip of that jack is called the "tip"
and the rest part behind the tip after a black strip is the ring So connect these two connections with the circuit and you will be done
Step 7: THe ENd
Follow tese steps and you are done. but if you face any problem feel free to write comments or mail me at email@example.com