ELECTRICAL

Circuits Outline

• 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 DiagramInput Voltage Range : 7V – 36V Output Voltage: 5V

InputOutput

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

->

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?