ELECTRICAL
Circuits Outline
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Power Hub
Microcontroller
Sensor Inputs
Motor Driver
Power Hub
• Purpose:
– Regulate input voltage into the circuit
– Allows for flexible power supplies that can be used for
your robot (input 7V – 36V; output 5V)
– Most ICs and electronic components use 5V
• Comprised of a voltage regulator and filtering
capacitors
• Capacitors act like a buffer before current flows
to the load
• Voltage regulator reduces the range of voltages
down to a set value
Circuit Diagram
Input Voltage Range : 7V – 36V
Input
Output Voltage: 5V
Output
Microcontroller
• A small computer on an IC that contains a
processor core, memory, I/O peripherals
• Purpose
– The brain of the robot!!!
– Programmable – conveniently control behaviour
of the robot
• We will be using the ATMega 328-PU
microcontroller
Atmega 328 Pin Assignments
Microcontroller Configuration
• Requires:
– Vcc and GND connections
– Analog Reference (set to Vcc)
• Value used as the top of the analog input range
– Internal Clock (16Mhz Crystal)
• Used as clock input to microcontroller
• ATMega328-p contains 13 digital and 6 analog
pins to be used as I/O peripherals
Microcontroller Configuration
Sensor Inputs
Analog Signals
– Continuous
– Subject to electrical
noise
Digital Signals
• Not continuous
• Uses specific values to
represent information
Integration of Microcontroller and
Sensors
• ATMega328P-PU Pins 23-28 can be used as
Analog Input readings from your sensors
• Possible Sensors to be used:
– Proximity Sensors
• Detect presence of nearby objects
– Line Sensors
• Distinguish between white surfaces and black surfaces
• Used to detect bounds for SUMO Arena
Motor Driver
• Purpose:
– Governs the performance of an electronic motor
• H-bridge circuits are used to control motors
– Enables a voltage to be applied in either direction
across a load (controls rotational direction)
Motor Driver
• We will be using L293D Motor Driver IC
– Cheap and easy to use
– Works well with the Microcontroller
– No need to build an H-Bridge circuit
L293D Pin Assignments
Motor Driver Configuration
• Requires
– GND and VCC connections
– Enable pin connections from the Microcontroller
– Input pin connections from the Microcontroller
– Output pins connected to motors
– Vs – voltage signal to power the motors
Motor Driver Configuration
Integration of Microcontroller and
Motor Driver
ATMega328-P
• Digital I/O Pin 12
• Digital I/O Pin 13
• Digital I/O Pin 14
• Digital I/O Pin 19
• Digital I/O Pin 18
• Digital I/O Pin 17
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L293D Motor Driver
• Enable1 Pin 1 (MOTOR 1)
• Input 1 Pin 2 (MOTOR 1)
• Input 2 Pin 7 (MOTOR 1)
• Input 4 Pin 15 (MOTOR 2)
• Input 3 Pin 10 (MOTOR 2)
• Enable2 Pin 9 (MOTOR 2)
Functionality
• In order to turn the right motor,
– an enable signal must be given to PIN 9 from the
microcontroller
– Pins 10 and 15 must set to either HIGH and LOW
or LOW and HIGH
– Pin 16 must be connected to a 5V power source
Functionality
• In order to turn the left motor,
– an enable signal must be given to PIN 1 from the
microcontroller
– Pins 2 and 7 must set to either HIGH and LOW or
LOW and HIGH
– Pin 8 must be connected to a 5V power source
End Breadboard Configuration
QUESTIONS?