Robotycs - YLab Robotics Group Toy Hacking Workshop Part 2 November 11, 2015

Transcription

1 Robotycs - YLab Robotics Group Toy Hacking Workshop Part 2 November 11, 2015

2 Robot Talk Ross Lunan What do we build Robots with? With whatever you can find in your junk-box, get from lots of suppliers Typical Controllers/OS Arduino (C++), Raspberry Pi (Linux/Python), Beaglebone (Linux), Linux, Python, Scratch, Jscript, ROS, etc. Chassis, Sensors, Motors, LEDs, wireless devices, wires Patience and perseverance! While Robotic devices can take many forms, follows is an example of a basic vehicle hardware 2

3 Sample Basic Robot Vehicle Hardware (Follows from J. Lau & P Tan How to Build a robot in 10 Minutes) Hardware: Chassis (anything that will hold the robot) Motor and Wheel Microcontroller Arduino(Uno, Leonardo, Filo ), Raspberry Pi, Motor Driver (H-bridge) L298N Motor Shield Battery holder and battery $36/kit $26/kit $13 (w/nimh batteries $26 $16 $6/pair $6/pair

4 What s an Arduino? Arduino is an open-source physical computing platform based on a simple i/o board and a development environment that implements the standard language called Processing/Wiring. Arduino can be used to develop stand-alone interactive objects (i.e. robot devices) or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP). The open-source IDE can be downloaded for free (for Mac OS X, Windows, and Linux). It can be powered from the computer USB cable (usually during code development & testing) or battery pack (7-12 Vdc)

5 What s an Arduino? Cont d Interfaces ( 3.3 or 5v) can include 20 Digital Input or Output Pins (I/O), 7 Pulse Width Modulation (PWM) Channels (to control LED brightness or Motor Speeds), 12 Analog-to-Digital Converters to measure analog voltages from Sensors. Interface pins on standard models are arranged to enable attaching additional boards on top. These are called Shields and there are 100 s available to many useful functions. Many physical variations, smaller and larger are available to customize the application Communication to other devices to computers can be done by attaching external Bluetooth or WiFi devices.

6 What s a Motor Shield? A Motor and Servo Shield is an Arduino (R3) compatible shield (hardware circuit board and components) designed to make connecting motors, servos and sensors to your Arduino-based development board as fast and easy as possible. A separate power connection for the servo or motor allows customization to the optimum device specifications. The external shield is mandatory as the basic Arduino I/O does not provide sufficient power to directly drive a servo or motor A custom Library code file is available that increases the Arduino basic coding language specific to this hardware. There is a wide choice of Motor and Servo Shields depending on the end device requirements, available a completely built or kits requiring soldering.

7 What is a Chassis Base? As in any vehicle a frame is required to hold all the mechanical components, including wheels, motors, control devices. For a conventional flat surface vehicle, choices are usually 2, 4, 6 motor/wheel assemblies However there are 100 s of possible variations including flying, swimming, animal or insectoid like devices.

8 Arduino Controller Configuration DC Power (8-12 Vdc USB Serial Port for uploading code and Serial Monitor Pin Numbers in the program dir_b = 13 dir_a = 12 pwm_b = 11 BluetoothTx = 9 bluetoothrx = 10 pwm_a = 3 //Set control pins to be outputs pinmode(pwm_a, OUTPUT); pinmode(pwm_b, OUTPUT); pinmode(dir_a, OUTPUT); pinmode(dir_b, OUTPUT);

9 What is Digital I/O? ( The D or A pins on the Arduino can be configured as either inputs or outputs. Input: Arduino (Atmega) pins default to inputs, so they don't need to be explicitly declared as inputs with pinmode() when you're using them as inputs. Pins configured this way are said to be in a highimpedance state. Output: Pins configured as OUTPUT with pinmode() are said to be in a low-impedance state. This means that they can provide a substantial amount of current to other circuits. Atmega pins can source (provide positive current) or sink (provide negative current) up to 40 ma (milliamps) of current to other devices/circuits. This is enough current to brightly light up an LED (don't forget the series resistor), or run many sensors, for example, but not enough current to run most relays, solenoids, or motors. */ blink.ino /* int ledpin = 13; // LED connected to digital pin 13 void setup() { pinmode(ledpin, OUTPUT); // sets the digital pin as output void loop() { digitalwrite(ledpin, HIGH); // sets the LED on delay(1000); // waits for a second digitalwrite(ledpin, LOW); // sets the LED off delay(1000); // waits for a second

10 What is PWM I/O? ( Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off. This on-off pattern can simulate voltages in between full on (5 Volts) and off (0 Volts) by changing the portion of the time the signal spends on versus the time that the signal spends off. The duration of "on time" is called the pulse width. To get varying analog values, you change, or modulate, that pulse width. If you repeat this on-off pattern fast enough with an LED for example, the result is as if the signal is a steady voltage between 0 and 5v controlling the brightness of the LED. In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogwrite() is on a scale of 0-255, such that analogwrite(255) requests a 100% duty cycle (always on), and analogwrite(127) is a 50% duty cycle (on half the time) for example.

11 Motor Shield Configuration 2a 2b A dir_b = 13 dir_a = 12 1a Pwm switch 1b pwm_b = 11 //Set motor stop, 0% duty cycle analogwrite(pwm_a, 0); //Set motor direction cw, 1a=2b=high, 1b=2a=low digitalwrite(dir_a, HIGH); //Set motor direction ccw, 1b=2a=high, 1a=2b=low digitalwrite(dir_b, LOW); pwm_a = 3

12 usb_tether_remote_test_motors.ino - Software /* usb_tether_remote_test_motors.ino * For UNO, NOT DUE or Leonardo * Version of remote_test_motors w/usb tether connected to H/W Serial Rx-In D0/Tx-Out D1 * Hardware Serial Monitor port (Serial command). * Added code to control direction from characters received from * Bluetooth radio connected to SoftwareSerial library serial Arduino Rx-In D10/Tx-Out D11 * Android Client: hobbyprojects.com forward="a", backward="b", turn left=c, * turn right="d", stop="e", 360 deg CW="F", 360 deg CCW="G" * * Disregard the controller implementation * Anduino code from Instructables.com Android-bot-remote-control * * revised move functions to add "turn" CW and CCW, input speed for future * Based on test_motors.ino * Canada Robotics Motor Shield * * *** Open Arduino IDE Serial monitor set to 9600 b/s *** */ #include <SoftwareSerial.h> // Library to enable serial tx/rx on any pin int bluetoothtx = 9; // Arduino Rx-In from Tx-O data Out pin of Bluetooth module int bluetoothrx = 10; // Arduino Tx-Out to Rx-I data In pin of Bluetooth module // Note the Arduino Rx/Tx Pins are crossed over with Bluetooth Tx/Rx pins SoftwareSerial bluetooth( bluetoothtx, bluetoothrx); // connected to Arduino Rx-In, Tx-Out D pin // // set pin # const int pwm_a = 3; const int pwm_b = 11; const int dir_a = 12; const int dir_b = 13; const int speedbot = 255; char incomingbyte = 0; // incoming byte from Serial Terminal or Bluetooth link // set pin modes

13 usb_tether_remote_test_motors.ino Software Page 2 void setup() { //Set control pins to be outputs pinmode( pwm_a, OUTPUT); // Right Motor speed pinmode( pwm_b, OUTPUT); // Left Motor speed pinmode( dir_a, OUTPUT); // Right Motor direction Fwd or Back pinmode( dir_b, OUTPUT); // Left Motor direction Fwd or Back //initial set up straight forward, no speed digitalwrite( dir_a, HIGH); //Reverse motor direction, 1 high, 2 low digitalwrite( dir_b, HIGH); //Reverse motor direction, 3 low, 4 high analogwrite( pwm_a, 0); //set both motors to not move analogwrite( pwm_b, 0); Serial. begin(9600); // Begin serial monitor and keyboard at 9600 b/s bluetooth. begin(9600); // Begin Software Serial data interface at 9600 b/s // setup() # void loop() { /* Comment out test-motors commands *********************** // see if there's incoming serial data on usb tether or bluetooth link: int serialbyteready = Serial. available() > 0; int bluetoothbyteready = bluetooth. available() > 0; if ( serialbyteready bluetoothbyteready) { // read the oldest byte in the serial buffer of either serial port if ( serialbyteready) { incomingbyte = Serial. read(); else if ( bluetoothbyteready) { incomingbyte = bluetooth. read(); // action depending on the instruction // as well as sending a confirmation back to the appi

14 usb_tether_remote_test_motors.ino Software Page 3 switch (incomingbyte) { case 'A': forward(speedbot); Serial.println("Going forward"); break; case 'C': turn(speedbot, true); Serial.println("Turning left"); break; Case 'D': turn(speedbot, false); Serial.println("Turning right"); break; case 'B': backward(speedbot); Serial.println("Going backwards"); break; case 'E': stopped(); Serial.println("Stopping"); - break; case 'F': spin(speedbot, true); // CW Serial.println("Spinning CW"); break; case 'G': spin(speedbot, false); // CCW Serial.println("Spinning CCW"); break; default: // if nothing matches, do nothing break; //case // if //loop()

15 Build a robot in 10 minutes - Software void forw() { // no pwm defined digitalwrite(dir_a, HIGH); //Reverse motor direction, 1 high, 2 low digitalwrite(dir_b, HIGH); //Reverse motor direction, 3 low, 4 high void back() { // no pwm defined digitalwrite(dir_a, LOW); //Set motor direction, 1 low, 2 high digitalwrite(dir_b, LOW); //Set motor direction, 3 high, 4 low void forward() { //full speed forward digitalwrite(dir_a, HIGH); //Reverse motor direction, 1 high, 2 low digitalwrite(dir_b, HIGH); //Reverse motor direction, 3 low, 4 high analogwrite(pwm_a, 255); //set both motors to run at (100/255 = 39)% duty cycle analogwrite(pwm_b, 255); void backward() { //full speed backward digitalwrite(dir_a, LOW); //Set motor direction, 1 low, 2 high digitalwrite(dir_b, LOW); //Set motor direction, 3 high, 4 low analogwrite(pwm_a, 255); //set both motors to run at 100% duty cycle (fast) analogwrite(pwm_b, 255); void stopped() { //stop digitalwrite(dir_a, LOW); //Set motor direction, 1 low, 2 high digitalwrite(dir_b, LOW); //Set motor direction, 3 high, 4 low analogwrite(pwm_a, 0); //set both motors to run at 100% duty cycle (fast) analogwrite(pwm_b, 0);

16 Build a robot in 10 minutes - Software void fadein() { // fade in from min to max in increments of 5 points: for(int fadevalue = 0 ; fadevalue <= 255; fadevalue += 5) { // sets the value (range from 0 to 255): analogwrite(pwm_a, fadevalue); analogwrite(pwm_b, fadevalue); // wait for 30 milliseconds to see the dimming effect delay(30); void fadeout() { // fade out from max to min in increments of 5 points: for(int fadevalue = 255 ; fadevalue >= 0; fadevalue -= 5) { // sets the value (range from 0 to 255): analogwrite(pwm_a, fadevalue); analogwrite(pwm_b, fadevalue); // wait for 30 milliseconds to see the dimming effect delay(30); void astop() { //stop motor A analogwrite(pwm_a, 0); //set both motors to run at 100% duty cycle (fast) void bstop() { //stop motor B analogwrite(pwm_b, 0); //set both motors to run at 100% duty cycle (fast)

17 USB Tether Serial Monitor - Control The Serial Monitor is a separate pop-up window that acts as a separate terminal that communicates by receiving and sending Serial Data. With USB cable connected beteen Arduino and PC, open a separate window with Tools-Serial Monitor, set bit-rate. Serial Data is sent over a single wire (but usually travels over USB in our case) and consists of a series of 1's and 0's sent over the wire. Data can be sent in both directions (In our case on two wires). void setup() /****** SETUP: RUNS ONCE ******/ { Serial.begin(9600); Serial.println("--- Start Serial Monitor SEND_RCVE ---"); Serial.println(" Type in Box above,. "); Serial.println("(Decimal)(Hex)(Character)"); Serial.println(); //--(end setup )---

18 New Arduino Functions Comments: */ This is a comment */ // So is this #include SoftwareSerial.h, SoftwareSerial name(rx-in pin, Tx-Out pin): Calls an included Library to set up a two-way serial interface on selected digital pins. Serial.begin(9600): Starts the Serial Terminal link at 9600 b/s Name.begin(9600); Start the SoftwareSerial link at 9600 b/s int serialbyteready=serial.available()>0; define a boolean variable and checks if a byte is in the receiver buffer if( ) {do this if true else if () {do this if true Check statements and direcvt action Switch ( a byte ) { case A ; do this and this; break ; skip all other case statements default: // if nothing matches, do nothing break;

19 Next Step Bluetooth Remote Control Transmits characters from a Bluetooth device, i.e.andoid running an APP to the Arduino Need to connect a Bluetooth module to your Arduino just 4 wires, +3.3 Vdc, Gnd, Tx-Out to Arduino Rx-In, Rx-In to Tx-Out. Suggested is Wireless Module HC-05 It operates at 9600 bit/s identical to the USB tether. No change to the code is required Download from Google Play: Bluetooth Robot Remote Control by Hobbyproject.com

20 Information Googling and.. YLab: Supplers: (Jade Robot), (Bookstore), lotsa vendors.. Organizations: IEEE Robotics Society: Magazines: Servo Robot Nuts and Volts Competitions: First Robotics: Underwater robotics: MATE: 20

21 Upcoming YLab events Joint YLab/York Region Amateur Radio Club: Wed., Nov. 18, 2105 at David Dunlap Observatory (Richmond Hill) YLab Robotycs: Wed., Nov. 25, 2015, 7-9 pm Location TBD

22 Other local upcoming events Markham Library: 3D design & Printed Workshops Nov 8, 19, 25, Dec 2, Register at Markham Cave: MPL s Media Makespace: thecavemarkham.blogspot.ca

23 UNTIL NEXT MONTH NOVEMBER 25, 2015 Location : TBD, See for Robot Talk topic and Activities