Computer Science for

High School

Discovery LabSchool of Computing & Information System

Florida International University

Second Day Schedule» First Day Lecture Review» Introduction to Embedded Systems» Digital I/O» Serial Communication» Lunch» Discovery Lab Tour» Analog I/O» Practice » Q&A

First Day Lecture Review» Raspberry Pi

» Python

Introduction to Embedded Systems

» An embedded system is a computer system with a dedicated function

» Embedded systems control many devices in common use today

» Processing Cores ˃ microcontrollers or digital signal processors (DSP)˃ ATMega, PIC, ARM, etc.

Variety of embedded systems

» Consumer electronics

» Automobiles,

» Transportation systems

» Medical equipment

» Wireless sensor networking

» Home Automation

Arduino & mBed FRDM» Better Performance

» More GPIOs

» Accelerometer and Capacitive Slider Sensor

» One RGB LED

» Open SDA (Open-standard Serial and Debug Adapter)

FRDM Architecture

FRDM Pin-out

mBed FRDM board Development Set up

» Login ID : team00» Password : pw00team

» Plugin FRDM Board to USB port on PC

» https://mbed.org/handbook/Windows-serial-configuration

» http://mbed.org/handbook/mbed-FRDM-KL25Z-Getting-Started

» http://mbed.org/handbook/mbed-FRDM-KL25Z-Examples

» #include "mbed.h"

» DigitalOut myled(LED1);

» int main() {» while(1) {» myled = 1;» wait(0.2);» myled = 0;» wait(0.2);» }» }

Digital Out

* Try to change wait time

» The most common function of a diode is to allow an electric current to pass in one direction, while blocking current in the opposite direction˃ Protect circuits from high voltage surges

- Avalanche diodes˃ Regulate voltage - Zener diodes

˃ Electronically tune radio and TV receivers - Varicap diodes

˃ Generate radio frequency oscillations - Tunnel diodes, Gunn diodes, IMPATT diodes

˃ Convert light into either current or voltage - Photodiode

˃ Produce light - Light Emitting Diodes (LED)

Diode

LED (Light Emitting Diode)

Bread Board Set up

Bus(power line)

Vertically 5 pin

Connected

Vertically 5 pin

Connected

Bread Board Set up» Busser

˃ Pin (-) (e , 1)˃ Pin (+) (f , 6)

Bread Board Set up» Ground & Power line Connection

Dual Motor Driver

Voltage Regulator

LED

Bread Board Set up» Power Connection between Bread Board and FRDM

Power & Ground

Bread Board Set up» Power Connection between Bread Board and FRDM

Power & Ground

Bread Board Set up» Connect 4 LEDs

» White PTC5» Green PTC6» Yellow PTC10» Red PTC16

» Make LEDs blink with below patterns

» Make a led-control program which can control 4 leds with different blinking time˃ Using if else˃ Using switch case

Try to make patterns W R YG

Serial Communcation » #include "mbed.h"» » Serial pc(USBTX, USBRX); // tx, rx» PwmOut led(LED1);» » float brightness = 0.0;» » int main() {» pc.printf("Press 'u' to turn LED1 brightness up, 'd' to turn it down\n");» » while(1) {» char c = pc.getc();» if((c == 'u') && (brightness < 0.5)) {» brightness += 0.01;» led = brightness;» }» if((c == 'd') && (brightness > 0.0)) {» brightness -= 0.01;» led = brightness;» } » » }» }

Connect to your mbed Microcontroller with a Terminal program and uses the 'u' and 'd' keys to make LED1 brighter or dimmer

» What is it?˃ Controlling power to inertial electrical devices˃ Average voltage and current controlled by turning switch

» What for?˃ Modern electronic power switches˃ The main advantage of PWM is that power loss in the switching

devices is very low˃ Relatively low cost

Pulse-width Modulation

» Applications˃ Fans

˃ Pumps

˃ Robotic Servo

˃ Stepper Motor

˃ Telecommunication

Pulse-width Modulation

Pulse Width Modulation#include "mbed.h"

PwmOut led(LED1); int main() { while(1) { for(float p = 0.0f; p < 1.0f; p += 0.1f) { led = p; wait(0.1); } } }

Let’s Make a Ticker#include "mbed.h"

PwmOut led(LED1); int main() { while(1) { for(float p = 0.0f; p < 1.0f; p += 0.1f) { led = p; wait(0.1); } } }

Let’s Make a Ticker#include "mbed.h"

PwmOut led(LED1); int main() { while(1) { for(float p = 0.0f; p < 1.0f; p += 0.1f) { led = p; wait(0.1); } } }

* Try to connect Buzzer and change delay

Analog In#include "mbed.h" AnalogIn ain(p19);DigitalOut led(LED1);

int main() { while (1){ if(ain > 0.3) { led = 1; } else { led = 0; } } }

* Try to connect Buzzer and change delay

Analog Out#include "mbed.h" AnalogOut signal(p18); int main() { while(1) { for(float i=0.0; i<1.0; i+=0.1) { signal = i; wait(0.0001); } }}

* Try to connect Buzzer and change delay

Import Open Library

Motor Driver» Dual-H-bridge motor driver: can drive two DC motors» Motor supply voltage: 2–11 V» Logic supply voltage: 2–7 V» Output current: 1.2 A continuous (1.5 A peak) per motor» One PWM and One DigitalOut per DC motor» Logic High for Enabling This Driver

Motor Driver

Step-Up/Down Voltage Regulator» Input voltage: 2.7 V to 11.8 V» Fixed 5 V output with +5/-3% accuracy» Typical continuous output current: 500 mA to 1 A» The SHDN pin can be driven low (under 0.4 V) to power

down the regulator .

Q & A