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 Diagram Input Voltage Range : 7V – 36VOutput Voltage: 5V Input 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 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?