Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 1 Iwan Setiawan IoT Experiments: LED Switchingon/off 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 2 Iwan Setiawan Previous Week’s Material ● Setting up Raspberry Pi, plus remote access ● Practices on Raspberry Pi OS, e.g. CLI ● Starting to learn electronics, GPIO, observation * https://raspberrypi.org/documentation/ again √ a simple 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 3 Iwan Setiawan IoT Assignment 1 ● Raspberry Pi 4 Model B specifications – System-on-chip: Broadcom BCM2711 – Instruction set: ARM v8 – CPU, GPU: Quad-core Cortex-A72 64-bit @1.5GHz, VideoCore VI ● Useful websites – pinout.xyz: An interactive reference to the Raspberry Pi GPIO pins – resistorcolorcodecalc.com: Identifying resistor value and tolerance – gpiozero.readthedocs.io: Documentation of an easy-to-use GPIO library 500 MHz included in RasPi OS * https://raspberrypi.org/products/raspberry-pi-4-model-b/specifications/ RPi.GPIO pigpio 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 4 Iwan Setiawan Objectives ● Learn basics of electronic components+tools ● Learn how to connect electronic components to the Raspberry Pi ● Learn how to interact with the electronic compo- nents, specifically LEDs, through Python programs 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 5 Iwan Setiawan Contents ● Electronic circuits prototyping ● Python programming on Raspberry Pi with Mu editor and GPIO Zero library ● Setting up and running experiment set 1 – LED switching and controlling – Traffic lights simulation 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 6 Iwan Setiawan Sensor and Actuator ● Sensor: sensing or measuring the environment ● Actuator: acting or interacting with the environment “read” “write” Analog signal Compute Storage Digital signal Stallings, 2016 Communications 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 7 Iwan Setiawan Sensor and Actuator ● Sensor: sensing or measuring the environment ● Actuator: acting or interacting with the environment “read” “write” Analog signal Compute Storage Digital signal Stallings, 2016 Communications 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 8 Iwan Setiawan Sensor and Actuator ● Sensor: sensing or measuring the environment ● Actuator: acting or interacting with the environment “read” “write” Analog signal Compute Storage Digital signal Stallings, 2016 Communications 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 9 Iwan Setiawan Sensor and Actuator ● Sensor: sensing or measuring the environment ● Actuator: acting or interacting with the environment “read” “write” Analog signal Compute Storage Digital signal Stallings, 2016 Communications 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 10 Iwan Setiawan Electronic Components ● Resistor, electrical resistance ● Capacitor, store electrical energy or “charge” ● Photoresistor, or “light sensor” ● Light-emitting diode (LED), or “indicator” ● Buzzer, or “beeper” current limiting, etc. Piezoelectric Decreasing resistance when exposed to light 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 11 Iwan Setiawan Electronic Tools ● Breadboard for electronic prototyping ● Jumper wires/cables for interconnecting ● Fritzing for designing electronic circuits – Breadboard – Schematic – PCB * https://fritzing.org/ * http://dl.kuliax.net/acnt/iot/fritzing/ +Code 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 12 Iwan Setiawan Electronic Tools + 3V3 GND 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 13 Iwan Setiawan Electronic Tools + 3V3 GND 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 14 Iwan Setiawan Mu and GPIO Zero ● Mu, a simple Python editor ● GPIO Zero, an easy-to-use GPIO library 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 15 Iwan Setiawan General-Purpose Input/Input (GPIO) ● Interfacing between Raspberry Pi and electronic components ● Raspberry Pi 40-pin GPIO header – Command: pinout – Website: pinout.xyz 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 16 Iwan Setiawan Raspberry Pi Foundation, CC By-SA 4.0 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 17 Iwan Setiawan Organizing Your Mess ● Sort your jumper wires/cables – F/F, M/M, M/F – Light or dark colors ● Check if your cables/connections are good. Buzzer? ● Positive and negative sides, e.g. top and down ● Open your references, e.g. pinout, GPIO Zero doc ● Be careful 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 18 Iwan Setiawan Preparation ● Raspberry Pi 4 set +Ethernet cable ● Breadboard ● Jumper wires ● Resistors ● Capacitor ● LEDs ● LDR ● Button 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 19 Iwan Setiawan LED Lighting ● Build the circuit 1. Resistor and LED 2. GND pin to “-” rail 3. 3V3 pin to “+” rail ● Make sure everything is OK before connecting the “+” rail to the component rail 3V3 GND Be careful and pray first + Comes late Indicates that you need to take a picture of your work 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 20 Iwan Setiawan LED Switching on/off ● Use a jumper wire to connect GPIO 4 pin to the positive terminal of the circuit ● Open REPL shell ● Type this line one by one from gpiozero import LED led = LED(4) led.on() led.off() Importing LED module from gpiozero package See gpiozero.LED class* GPIO 4 * https://gpiozero.readthedocs.io/en/stable/api_output.html#led 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 21 Iwan Setiawan LED Flashing ● Create a new file, led_flash.py ● Type this code, save, and run from gpiozero import LED from time import sleep led = LED(4) while True: led.on() sleep(1) led.off() sleep(1) GPIO 4 * https://gpiozero.readthedocs.io/en/stable/api_output.html#led 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 22 Iwan Setiawan LED Switching on/off with Button ● Create a new file, led_sw.py ● Type this code, save, and run from gpiozero import LED, Button from signal import pause led = LED(4) button = Button(21) button.when_pressed = led.on button.when_released = led.off pause() GPIO 4 GPIO 21 * https://gpiozero.readthedocs.io/en/stable/api_input.html#button 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 23 Iwan Setiawan LED Controlling with LDR ● Create a new file, led_ldr.py ● Type this code, save, and run from gpiozero import LED, LightSensor from time import sleep led = LED(4) ldr = LightSensor(12) threshold = 0.3 while True: if ldr.value < threshold: print(“It’s dark, switch on the light!”) print(ldr.value) led.on() sleep(5) led.off() else: led.off() GPIO 4 GPIO 12 - * https://gpiozero.readthedocs.io/en/stable/api_input.html#lightsensor-ldr 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 24 Iwan Setiawan Simple Traffic Light Simulation 1 ● Create a new file, traffic_light1.py ● Type this code, save, and run from gpiozero import LED from time import sleep red = LED(4) amber = LED(12) green = LED(21) while True: red.on() sleep(10) amber.on() sleep(1) green.on() amber.off() red.off() sleep(10) green.off() amber.on() sleep(1) amber.off() 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 25 Iwan Setiawan Simple Traffic Light Simulation 2 ● Create a new file, traffic_light2.py ● Type this code, save, and run from gpiozero import TrafficLights from time import sleep from signal import pause lights = TrafficLights(4, 12, 21) def light_sequence(): while True: yield(1, 0, 0) #red sleep(10) yield(0, 1, 0) #amber sleep(1) yield(0, 0, 1) #green sleep(10) yield(0, 1, 0) #amber again sleep(1) lights.source = light_sequence() pause() * https://gpiozero.readthedocs.io/en/stable/recipes.html#traffic-lights 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 26 Iwan Setiawan IoT Assignment 2 ● Design and build a pair of traffic lights simulation for vehicles and pedestrians – Use the information, e.g. cycle time, etc., that you observed from Assignment 1 ● Cut the cycle time to ½ if necessary ● Descriptions and explanations in the report – Add a button to crossing light by giving delay first before “green”, e.g. 8 seconds – Add a buzzer to signal pedestrians when crossing the road ● Long beeping for the first half of the crossing time ● Short beeping for the last half ● Python code – Use functions for each light switch, button, and buzzer – Use conditional or control flow for button and buzzer – Use exceptions handling for keyboard interupt, i.e. Ctrl+C coordinated * https://docs.python.org/3.9/tutorial/errors.html#handling-exceptions √ Be creative 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 27 Iwan Setiawan Results to be Uploaded ● Experiment results: photos and explanations ● Assignment 2 results – Fritzing export image using Breadboard view – Photos and a demo video showing the results – Source code, screenshots/figures, and explanations Upload your experiment and assignment 2 results to Moodle ● Using one PDF file ● One group, one document ● Upload your demo video somewhere, only attach the URL to the doc. 06/03 9pm code experiment 

Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 28 Iwan Setiawan Resources ● Raspberry Pi Foundation, “Physical computing with Python,” 2020. [Online]. Available: https://projects.raspberrypi.org/en/projects/phys ical-computing