Rover 5 tracked robot chassis

Rover 5 is a new breed of tracked robot chassis designed specifically robotic usage and carried PCB circuit. The chassis can be upgraded into two or four motors and encoders making it ideal for mecanum wheels. There are two brushed DC motors with 210mA free run and 2.4A of stall current at 7.2V. The body was created by durable plastic and it can move for 1km/hour. 

As u can see, picture above show the internal body of robot chassis which contain 2 motors in left and right side. Each motor connected with 2 wires (red and black) for supply and also ground. These wire will connected to TIP120 on the circuit and interface with ATmega328.

The instructions provides by an ATmega328  are HIGH or LOW. High means 5 volts and Low is 0 volts. The operations of TIP120 is like a switching mode that control the input for the motors. 

Referring to the table above, a gas sensor will operate when the analog output for the sensor is more than 2.1 volts,meanwhile obstacle sensor will detect the object in front of the robot when analog output is more than 1.6 volts.

Once the gas sensor detecting a liquefied petroleum gas or obstacle sensor detecting a barrier, the motor an buzzer will automatically switch off.

There will be 3 line sensor operating the system especially the motors. When line sensor 1 detecting a black line, both motor of the robot will be on. On the other hands, if line sensor 0 or line sensor 2 will control either motor 1 or motor 2 to move.

Voltage regulator (IC 7805)

IC 7805 is a voltage regulator integrated circuit. It is a member of 78xx series of fixed linear voltage regulator ICs. The voltage source in a circuit may have fluctuations and would not give the fixed voltage output. The voltage regulator IC maintains the output voltage at a constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide. 7805 provides +5 volts regulated power supply. Capacitors of suitable values can be connected at input and output pins depending upon the respective voltage levels.

The regulator functions by using a diode to clamp the output voltage at 5 VDC regardless of the input voltage. Excess voltage is converted to heat and dissipated through the body of the regulator. If a DC supply of greater than 12 volts is used, excessive heat will be generated and the board may be damage. If a DC supply is less than 5 volts is used, insufficient voltage will be present at the regulators output.

For this project, input for all sensor should be equal to 5 volts. As mentioned before, all the sensors produce an analog output  within range 0- 5 volts. Therefore, this IC7805 are used to operate the system.