Do you want to build a robot
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The document outlines the process for building a robot using the Johnny-Five framework for Node.js, which supports various hardware including Raspberry Pi and Arduino. It details how to select hardware, set up a Raspberry Pi, implement JavaScript code for controlling sensors and actuators, and provides example programs for manipulating LEDs, buttons, and motors. Additional resources and further reading on related topics are also provided.
![Raspberry Pi GPIO
• Solder some headers on to the Raspberry
Pi Zero W for the GPIO pins
• Peripheral components (e.g. sensors,
actuators) attach via these pins
• 3.3V logic
• In Johnny-Five the pins are named
"P[header]-[pin]” e.g. P1-7](https://image.slidesharecdn.com/doyouwanttobuildarobot-170805073915/85/Do-you-want-to-build-a-robot-9-320.jpg)
![Piezo
const piezo = new five.Piezo("P1-32");
let val = 0;
board.loop(200, function() {
if (val ^= 1) {
// Play note a4 for 1/5 second
piezo.frequency(five.Piezo.Notes["a4"], 200);
}
});](https://image.slidesharecdn.com/doyouwanttobuildarobot-170805073915/85/Do-you-want-to-build-a-robot-26-320.jpg)
Do you want to build a robot
- 4. JS Robotics • http://johnny-five.io/ • https://www.espruino.com/ • https://tessel.io/ • https://docs.particle.io/reference/javascript/ • https://cylonjs.com/ • http://jerryscript.net/ • http://mujs.com/ • http://duktape.org/
- 6. Johnny-Five • Open Source JavaScript Robotics Framework for Node.js https://github.com/rwaldron/johnny-five • Communicates with microcontrollers like Arduino using the Firmata protocol • Runs on-board devices that can run Node.js e.g. Raspberry Pi, BeagleBone Black, via I/O Plugins
- 7. Set up Raspberry Pi Zero W (headless) • Install Raspbian: • https://www.raspberrypi.org/documentation/installation/installing- images/README.md • Create a file named wpa_supplicant.conf on the microSD card: network={ ssid="campjs" psk="morecoffee" } • Add a file named ssh (contents don’t matter) on the root of the microSD card to enable SSH on boot
- 8. Connect to the Raspberry Pi • Rpi uses mDNS so connect to the Pi over SSH: • ssh pi@raspberrypi.local • Default password is raspberry • (Make sure you change this) • Raspbian comes with node.js installed but if you are using something else, install node • Then use npm to install the dependencies: • npm install serialport • npm install johnny-five raspi-io
- 9. Raspberry Pi GPIO • Solder some headers on to the Raspberry Pi Zero W for the GPIO pins • Peripheral components (e.g. sensors, actuators) attach via these pins • 3.3V logic • In Johnny-Five the pins are named "P[header]-[pin]” e.g. P1-7
- 10. Breadboard • Use to prototype circuits without soldering by plugging in components and jumper wires • Numbered rows are connected • Some have power rails along the sides
- 12. Writing Johnny-Five programs 1. Create a JavaScript file (e.g. blink.js) on the Pi 2. Edit it using a text editor 3. Require the johnny-five library and raspi-io libraries into and set up the board object using the IO/Plugin const raspi = require('raspi-io'); const five = require('johnny-five'); const board = new five.Board({ io: new raspi() });
- 13. Ready event • When the board is ready for our code to start interacting with it and the attached sensors and actuators, it will trigger a ready event board.on('ready', () => { // code for sensors, actuators goes here });
- 14. LED • Create an Led instance // attach LED on pin 7 const led = new five.Led('P1-7'); // call strobe function to blink once per second led.strobe(1000); • We can change the parameter to the strobe function to change the speed: This input value is provided in milliseconds
- 15. LED blink program const raspi = require('raspi-io'); const five = require('johnny-five'); const board = new five.Board({ io: new raspi() }); board.on('ready', () => { // LED attached to RPi pin 7 (GPIO4) const led = new five.Led('P1-7'); led.strobe(500); });
- 16. Inputs - Sensors • Environmental conditions (e.g. temperature, humidity) • Magnetic (e.g. hall effect sensor) • Light (e.g. photo resistor) • Sound (e.g. microphone, piezo) • Movement / position (e.g. accelerometer, tilt switch) • User Input (e.g. button)
- 17. Inputs PHOTO RESISTOR Resistance changes depending on the amount of ambient light TILT SWITCH Detect orientation PUSH BUTTON Also known as momentary switch PIEZO ELEMENT Detect vibrations or knocks TEMPERATURE SENSOR Read the ambient temperature
- 18. Outputs • Light & Displays (e.g. LED, LCD screen) • Sound (e.g. Piezo buzzer) • Movement (e.g. Servo, DC Motor, Solenoid) • Relays
- 20. Digital vs Analog • Digital • discrete values (0 or 1) • Examples: tilt sensor, push button • Analog • continuous values • typically values for analog sensors are constrained within a range e.g. 0 – 255, 0 – 1023 • Example: photo resistor • Some components support both digital and analog
- 21. REPL • Read, Eval, Print Loop • A console for real-time interaction with the code • Expose our variables to the REPL to enable interactive control: board.on('ready', () => { // LED attached to RPi pin 7 (GPIO4) const myLed = new five.Led('P1-7'); myLed.strobe(500); board.repl.inject({ led: myLed }); });
- 22. Controlling the LED via the REPL • At the REPL prompt type commands followed by enter • Try: • stop, • on, • off, • toggle, • strobe e.g: >> led.stop()
- 25. PWM • Pulse Width Modulation • Produce analog output via digital pins • Instead of on or off, a square wave is sent to simulate voltages between 0V (off) and 5V (on) • Used to control motors, fade LEDs etc
- 26. Piezo const piezo = new five.Piezo("P1-32"); let val = 0; board.loop(200, function() { if (val ^= 1) { // Play note a4 for 1/5 second piezo.frequency(five.Piezo.Notes["a4"], 200); } });
- 27. Motors const leftMotor = new five.Motor({ pins: {pwm: "P1-35", dir: "P1-13"}, invertPWM: true }); const rightMotor = new five.Motor({ pins: {pwm: "P1-32", dir: "P1-15"}, invertPWM: true }); leftMotor.forward(150); rightMotor.forward(150); See Johnny-Five motor API http://johnny-five.io/api/motor/
- 28. Node-RED
- 29. • Anna’s blog: http://crufti.com • http://johnny-five.io/ • Node-ARDX (examples for Arduino): http://node-ardx.org Read more