Making Things Move and AVR Programming

CS4062 - Eoin Brazil - Semester 2 - 2008

Motion linear or

rotary

conversion issues

Types DC

Servo

Stepper

Gearhead

Servos and Motors

Servo

DC Motor

Stepper

Gearhead

2 Connections Continual spin, given current & voltage

Reversing current, reverses the direction

Increasing the voltage, spins faster, decreasing the voltage, slows the spin

High speed but low torque

Gearbox can add torque but at the expense of speed

DC Motor

DC Motor Example

DC Motor Example

DC Motor Example

DC Motor with gearbox Not fast but provide more torque

Servo Motor Gearhead motor with position feedback

Feedback is often from potentiometer

Pulsing the motor moves it to particular position within 180 degree range

Can’t move 360 degrees but can be positioned precisely within the 180 degree range

Gearhead Motor

Servo

Gearhead

Precise positioning & 360 degrees range

Move in discrete steps around a circle

A 200 step motor would move 1.8 degrees per step around the full 360 degrees

Continuous rotation in either direction

Good torque

Complex to connect

Stepper Motor

Linear Motion

Pull or Push

Types Solenoid

Actuator

Microactuator

Solenoids and Actuators

Microactuators

Actuator

Solenoid

Motor Characteristics gears or direct

rated voltage

current (efficiency) - stall / running

speed - spin / rpm, rps, Hz

torque

size, shaft diameter, shaft length

position resolution (Servos & Steppers)

Advanced Mediation Lisa McElligott, 2000 interactive confessional box

used real confessional box

confessor was computer program

interacted using a voice interface.

scripted interactions with random noises to add to immersion

suspension of disbelief

realism

Weave Mirror

Side and back views

Mechanical mirror

Any person standing in front of one of these pieces is instantly reflected on its surface.

Uses video cameras, motors and computers to achieve mirroring

Sound aspect - soothing sound

Daniel Rozin, Weave Mirror, 2007

Weave Mirror Daniel Rozin,

Weave Mirror, 2007

PWM Analog input / output

Duration of the digital pulse of voltage

Microcontroller - HIGH 5V or LOW 0V

``Fake’’ it using PWM

Duty cycle, ratio from low to high to low cycle

LED dimming, DC Motor speed control, Piezo speakers, RC Servo positioning

Pulse Width Modulation

Wiring Diagram

Schematic Diagram

Servo Motor Connections on Arduino

Black wire would go to Grd pin

Red wire would go to 5V power pin

White wire would go to one of the digital pins on the board

Colours can vary, Ground (black or brown), Power (red), Control (orange, yellow or white)

RC Servo Motor

/* * NewSerialServo * -------------- * Servo control from the Serial port * * Alteration of the control interface to use < and > keys * to slew the servo horn left and right. Works best with * the Linux/Mac terminal "screen" program. * * Created 10 December 2007 * copyleft 2007 Brian D. Wendt * http://principialabs.com/ * * Adapted from code by Tom Igoe, http://itp.nyu.edu/physcomp/Labs/Servo */

/** Adjust these values for your servo and setup, if necessary **/ int servoPin = 2; // control pin for servo motor int minPulse = 600; // minimum servo position int maxPulse = 2400; // maximum servo position int turnRate = 100; // servo turn rate increment (larger value, faster rate) int refreshTime = 20; // time (ms) between pulses (50Hz) /** The Arduino will calculate these values for you **/ int centerServo; // center servo position int pulseWidth; // servo pulse width int moveServo; // raw user input long lastPulse = 0; // recorded time (ms) of the last pulse

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/* * NewSerialServo * -------------- * Servo control from the Serial port * * Alteration of the control interface to use < and > keys * to slew the servo horn left and right. Works best with * the Linux/Mac terminal "screen" program. * * Created 10 December 2007 * copyleft 2007 Brian D. Wendt * http://principialabs.com/ * * Adapted from code by Tom Igoe, http://itp.nyu.edu/physcomp/Labs/Servo */

/** Adjust these values for your servo and setup, if necessary **/ int servoPin = 2; // control pin for servo motor int minPulse = 600; // minimum servo position int maxPulse = 2400; // maximum servo position int turnRate = 100; // servo turn rate increment (larger value, faster rate) int refreshTime = 20; // time (ms) between pulses (50Hz) /** The Arduino will calculate these values for you **/ int centerServo; // center servo position int pulseWidth; // servo pulse width int moveServo; // raw user input long lastPulse = 0; // recorded time (ms) of the last pulse

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Setup the necessary control values and variables to store

information

// Main program setupvoid setup() { pinMode(servoPin, OUTPUT); // Set servo pin as an output pin centerServo = maxPulse - ((maxPulse - minPulse)/2); pulseWidth = centerServo; // Give the servo a starting point (or it floats) Serial.begin(9600); Serial.println(" Arduino Serial Servo Control"); Serial.println("Press < or > to move, spacebar to center"); Serial.println(); }

void loop() { // wait for serial input if (Serial.available() > 0) { // read the incoming byte: moveServo = Serial.read(); // ASCII '<' is 44, ASCII '>' is 46 (comma and period, really) if (moveServo == 44) { pulseWidth = pulseWidth - turnRate; } if (moveServo == 46) { pulseWidth = pulseWidth + turnRate; } if (moveServo == 32) { pulseWidth = centerServo; } // stop servo pulse at min and max if (pulseWidth > maxPulse) { pulseWidth = maxPulse; } if (pulseWidth < minPulse) { pulseWidth = minPulse; } }

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// Main program setupvoid setup() { pinMode(servoPin, OUTPUT); // Set servo pin as an output pin centerServo = maxPulse - ((maxPulse - minPulse)/2); pulseWidth = centerServo; // Give the servo a starting point (or it floats) Serial.begin(9600); Serial.println(" Arduino Serial Servo Control"); Serial.println("Press < or > to move, spacebar to center"); Serial.println(); }

void loop() { // wait for serial input if (Serial.available() > 0) { // read the incoming byte: moveServo = Serial.read(); // ASCII '<' is 44, ASCII '>' is 46 (comma and period, really) if (moveServo == 44) { pulseWidth = pulseWidth - turnRate; } if (moveServo == 46) { pulseWidth = pulseWidth + turnRate; } if (moveServo == 32) { pulseWidth = centerServo; } // stop servo pulse at min and max if (pulseWidth > maxPulse) { pulseWidth = maxPulse; } if (pulseWidth < minPulse) { pulseWidth = minPulse; } }

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Setup servo its pin, its pulse, and its position. Setup serial connection

for control

// Main program setupvoid setup() { pinMode(servoPin, OUTPUT); // Set servo pin as an output pin centerServo = maxPulse - ((maxPulse - minPulse)/2); pulseWidth = centerServo; // Give the servo a starting point (or it floats) Serial.begin(9600); Serial.println(" Arduino Serial Servo Control"); Serial.println("Press < or > to move, spacebar to center"); Serial.println(); }

void loop() { // wait for serial input if (Serial.available() > 0) { // read the incoming byte: moveServo = Serial.read(); // ASCII '<' is 44, ASCII '>' is 46 (comma and period, really) if (moveServo == 44) { pulseWidth = pulseWidth - turnRate; } if (moveServo == 46) { pulseWidth = pulseWidth + turnRate; } if (moveServo == 32) { pulseWidth = centerServo; } // stop servo pulse at min and max if (pulseWidth > maxPulse) { pulseWidth = maxPulse; } if (pulseWidth < minPulse) { pulseWidth = minPulse; } }

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The serial input controls the servo by the ‘<‘ or ‘>’ and keep its speed within the safe range

// pulse the servo every 20 ms (refreshTime) with current pulseWidth // this will hold the servo's position if unchanged, or move it if changed if (millis() - lastPulse >= refreshTime) { digitalWrite(servoPin, HIGH); // start the pulse delayMicroseconds(pulseWidth); // pulse width digitalWrite(servoPin, LOW); // stop the pulse lastPulse = millis(); // save the time of the last pulse } }// END of Main program

// pulse the servo every 20 ms (refreshTime) with current pulseWidth // this will hold the servo's position if unchanged, or move it if changed if (millis() - lastPulse >= refreshTime) { digitalWrite(servoPin, HIGH); // start the pulse delayMicroseconds(pulseWidth); // pulse width digitalWrite(servoPin, LOW); // stop the pulse lastPulse = millis(); // save the time of the last pulse } }// END of Main program

Pulse the servo every 20ms, this is where the desired change actually happens and its based

on the previous serial input

Sketching your work

Bill Verplank Interaction Design

Sketchbook

Bill Buxton

Embodiment using Animatronics

Stefan Marti 2005, Autonomous

Interactive Intermediaries

2005, Physical Embodiments for Mobile Communication Agents

Kinematics Gears and mechanical

models Geometry of pure motion without

reference to force or mass

Cornell University Library, Kinematic Models for Design Digital Library (KMODDL)

Tutorials, models, e-books, e.g. Linkages

Chapter 3 in Building Robot Drive Trains

Examples from www.flying-pig.co.uk

PWM Tutorials

ITP Servo tutorial

Principial Labs Arduino Servo

Driving a Unipolar Stepper Motor

Driving a Bipolar Stepper Motor

Making an RC Servo wall following car

ITP Servo lab, uses a potentiometer to control the servo.

Arduino Library Software Servo Library

attach(int) Turn a pin into a servo driver.

detach() Release a pin from servo driving.

write(int) Set the angle of the servo in degrees, 0 to 180.

read() return that value set with the last write().

attached() return 1 if the servo is currently attached.

refresh() must call once every 50ms to keep servos updated, won't call more than every 20ms

setMinimumPulse(uint16_t) set the duration of the 0 degree pulse in microseconds. (default minimum value is 544 microseconds)

setMaximumPulse(uint16_t) set the duration of the 180 degree pulse in microseconds. (default maximum pluse value is 2400 microsconds)

Need to first send position with write() before you can receive any control signals

Projects and Prototyping Trade-offs

Projects and Prototyping Trade-offs

Re-programmable

Projects and Prototyping Trade-offs

Size matters

Existing Toolkits

Existing Toolkits

Sufficient foralmost all needs

Existing Toolkits

Sufficient foralmost all needs

Chips and PCBs

Arduino Advanced Arduino ATMega168

ATTiny13

Arduino Advanced Arduino ATMega168

Approx. ~$35

ATTiny13

Arduino Advanced Arduino ATMega168

Approx. ~$35

Approx. ~$4 ATTiny13

Arduino Advanced Arduino ATMega168

Approx. ~$35

Approx. ~$4 ATTiny13

Approx.~$1

AVR Programmer

AVR ATTiny13 Blinky

AVR ATTiny13 Blinky

/* Two LEDs, tied to pin b0 and to b1 which correspond to physical pins 5 and 6 on ATTINY13 are turned on for 100ms and then off for 200ms*/

#include <avr/io.h> #define F_CPU 1000000 // set to 1 MHz as delay.h needs F_CPU#include <util/delay.h>#include "pin_macros.h" // Leah Buechley's pin macros for AVRs - very useful

int main(void){ // Set Port B pins for 3 and 4 as outputs

b0_output; //initialize LED pinb1_output; //initialize LED pinb0_high; //LED is offb1_high; //LED is off

DDRB = 0x18; // In binary this is 0001 1000 (note that is bit 3 and 4)

for ( ; 1==1 ; ) // loop while 1 equals 1 - forever - C style loop{

// Set Port B pins for 3 and 4 as HIGH (i.e. turn the LEDs on) b0_low; //LED is on b1_low; //LED is on _delay_loop_2(65535); b0_high; //LED is off b1_high; //LED is off _delay_loop_2(65535);

}return 1;

}

/* Two LEDs, tied to pin b0 and to b1 which correspond to physical pins 5 and 6 on ATTINY13 are turned on for 100ms and then off for 200ms*/

#include <avr/io.h> #define F_CPU 1000000 // set to 1 MHz as delay.h needs F_CPU#include <util/delay.h>#include "pin_macros.h" // Leah Buechley's pin macros for AVRs - very useful

int main(void){ // Set Port B pins for 3 and 4 as outputs

b0_output; //initialize LED pinb1_output; //initialize LED pinb0_high; //LED is offb1_high; //LED is off

DDRB = 0x18; // In binary this is 0001 1000 (note that is bit 3 and 4)

for ( ; 1==1 ; ) // loop while 1 equals 1 - forever - C style loop{

// Set Port B pins for 3 and 4 as HIGH (i.e. turn the LEDs on) b0_low; //LED is on b1_low; //LED is on _delay_loop_2(65535); b0_high; //LED is off b1_high; //LED is off _delay_loop_2(65535);

}return 1;

}

Include the libraries and set the speed of chip

/* Two LEDs, tied to pin b0 and to b1 which correspond to physical pins 5 and 6 on ATTINY13 are turned on for 100ms and then off for 200ms*/

#include <avr/io.h> #define F_CPU 1000000 // set to 1 MHz as delay.h needs F_CPU#include <util/delay.h>#include "pin_macros.h" // Leah Buechley's pin macros for AVRs - very useful

int main(void){ // Set Port B pins for 3 and 4 as outputs

b0_output; //initialize LED pinb1_output; //initialize LED pinb0_high; //LED is offb1_high; //LED is off

DDRB = 0x18; // In binary this is 0001 1000 (note that is bit 3 and 4)

for ( ; 1==1 ; ) // loop while 1 equals 1 - forever - C style loop{

// Set Port B pins for 3 and 4 as HIGH (i.e. turn the LEDs on) b0_low; //LED is on b1_low; //LED is on _delay_loop_2(65535); b0_high; //LED is off b1_high; //LED is off _delay_loop_2(65535);

}return 1;

}

Setup LED pins, Data Direction Register and

turn LEDS off.

/* Two LEDs, tied to pin b0 and to b1 which correspond to physical pins 5 and 6 on ATTINY13 are turned on for 100ms and then off for 200ms*/

#include <avr/io.h> #define F_CPU 1000000 // set to 1 MHz as delay.h needs F_CPU#include <util/delay.h>#include "pin_macros.h" // Leah Buechley's pin macros for AVRs - very useful

int main(void){ // Set Port B pins for 3 and 4 as outputs

b0_output; //initialize LED pinb1_output; //initialize LED pinb0_high; //LED is offb1_high; //LED is off

DDRB = 0x18; // In binary this is 0001 1000 (note that is bit 3 and 4)

for ( ; 1==1 ; ) // loop while 1 equals 1 - forever - C style loop{

// Set Port B pins for 3 and 4 as HIGH (i.e. turn the LEDs on) b0_low; //LED is on b1_low; //LED is on _delay_loop_2(65535); b0_high; //LED is off b1_high; //LED is off _delay_loop_2(65535);

}return 1;

}

Loop - Turn the pins on, wait for 262ms, and

turn off. Repeat.

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

When Make is run, needs a target

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

Use avr-gcc to compile ‘c’ program

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

Use avr-gcc on `o’ obj file to create `elf ’ file

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

Use avr-objcopy to create rom from elf file

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

Use avrdube and a usbtiny to copy to the

ATtiny13 chip

# Makefile for sample_led_program for ATtiny13 chip# Note: to use makefile with a different chip change all# mmcu statements (-mmcu=attiny13) to reflect new chip # also change the part option (-p t13) for the avrdude install command

# default target when "make" is run w/o argumentsall: sample_led_program.rom

# compile sample_led_program.c into sample_led_program.osample_led_program.o: sample_led_program.c avr-gcc -c -g -O0 -Wall -mmcu=attiny13 sample_led_program.c -o sample_led_program.o

# link up sample_led_program.o into sample_led_program.elfsample_led_program.elf: sample_led_program.o avr-gcc sample_led_program.o -Wall,-nm,-Map=sample_led_program.map,--cref -mmcu=attiny13 -o sample_led_program.elf

# copy ROM (FLASH) object out of sample_led_program.elf into sample_led_program.romsample_led_program.rom: sample_led_program.elf avr-objcopy -O ihex sample_led_program.elf sample_led_program.rom

# command to program chip (invoked by running "make install")install: avrdude -c usbtiny -p t13 -e -U flash:w:sample_led_program.rom

# command to clean up junk (no source files) (invoked by "make clean")clean: rm -f *.o *.rom *.elf *.map *~

Clean up the files created

Call the Makefile

Call the Install part of Makefile which calls avrdude

Run avrdude, it reads the rom, writes it to the chip and verifies

this process

Sources for Parts Hacking / Disassembly

use existing high-tech, but inexpensive, objects, toys and devices as cheap source of parts for your projects

little specialist knowledge is required, photograph and document the disassembly

``Low tech sensors and actuators for artists and architects’’ provides examples, by Usman Haque and Adam Somlai-Fischer

Purchase / Stores Many parts are available locally in UL, ask.

Online vendors for electronic parts include farnell.com, mouser.com, and digikey.com

Sensors, shields, kits, servos can also be found from sparkfun.com or parallax.com

Many others, just small selection that I’ve used.

Things To Remember Safety first, last, and always

do not take another person’s work about the state of a piece of equipment, always check yourself and make sure its safe for you to work

use the right tool for the job

treat each tool with respect and rack them back in their correct place when they are not in use, don’t leave a dangerous tool loose when it can harm somebody else

don’t leave your safety glasses on the bench or in your pocket

don’t work on a live circuit, turn the power off first

don’t solder in an enclosed area without proper ventilation

read the datasheet first and double check it to be sure

get twice or three times the number of parts that you need for your circuit, you will make mistakes and sometimes you will have to throw an almost finished piece away