BRIEF DESCRIPTION :
This is a Master-Slave Robot in which the Slave imitates the Master line follower as shown in the video. USART (Universal Synchronous Asynchronous receiver transmitter) protocol is used to communicate between the Master and the Slave with the help of a RF module operating at 434 MHz.
434 MHz RF TRANSMITTER AND RECEIVER:
Basically the RF module has a RF Transmitter and a RF Receiver operating at 434 MHz. RF transmitter transmits serial data to the receiver through an antenna which is connected to the 4th pin of the transmitter. When logic “0” is applied to the transmitter there is no power supply to transmitter (Reason : The carrier is fully suppressed). When logic “1” is applied to the transmitter, the transmitter is turned ON and there is a power supply of 4.5 mA with 3 V voltage supply.
FEATURES OF RF MODULE:
- Receiver frequency 434 MHz
- Receiver typical frequency 105 Dbm
- Receiver supply current 3.5 mA
- Low power consumption
- Receiver operating voltage 5 V
- Transmitter frequency range 433.92 MHz
- Transmitter supply voltage 3 V~6 V
- Transmitter output power 4 V~12 V
STEP BY STEP INSTRUCTIONS AND CONNECTIONS:
Step 1:- Connect Vcc to the outer hub and ground to the inner hub. Connect either sides of the hub as shown below
Step 2:- Place the L293D (Motor Driver) on the bread board and connect its ground pins on either side
Step 3:- Since our battery is 8 V and we need only 5 V for our components, connect a voltage regulator (IC 7805). The input of the IC 7805 is given directly to Vs (pin 8) of motor driver and the output is connected to Vcc (Outer Hub).
Step 5:- Place the micro-controller (ATmega16) on the bread board and connect its Vcc(pin 10) to outer hub and ground (pin 11) to inner hub.
Step 6:- Connect the input of the L293D to the first four pins of Port B (output port) of the ATmega16.
Step 7:- In the Slave robot, connect the RF Receiver’s antenna, Vcc & ground. Then connect the data pin to TXD (pin 15) of ATmega16.
Step 8:- Lastly in the Master, give the RF transmitter’s antenna, Vcc and Gnd connections. The data pin of the transmitter must be connected to RXD (pin 14) of ATmega16.
CHALLENGES/ISSUES FACED DURING THIS PROJECT:
Since we were working with a RF module there was a problem of junk values being transmitted. Hence we had to load the program repeatedly.
Solution: This could be further improved by using a Bluetooth module in which transmission of garbage values doesn’t affect the project.
The second limitation was with respect to the distance; Since our RF works at 434 MHz, only a short distance could be covered.
The next problem we encountered was the baud rate. The robot did not work at a rate of 9600, hence after trail and error, 4800 was set as the baud rate.