[vc_row][vc_column width=”1/1″][vc_tour][vc_tab title=”Project Description” tab_id=”1389318119-1-85″][vc_column_text]Original: http://wiki.cs.mtholyoke.edu/mediawiki/rmc/index.php/Spring2012_Final_Report-Jingjing_%26_Liye

• Kowheeli is a robotic koala bear that also functions as an alarm clock.
• It can be controlled through a webpage.
• At the time set online by the user, she will sing songs.
• A picture of Kowheeli is shown below:

[/vc_column_text][/vc_tab][vc_tab title=”Materials Used” tab_id=”1389318119-2-66″][vc_column_text]

• Arduino UNO kit $35.0
  • An Arduino UNO board
  • A mini Breadboard
  • Connecting wires

• Two DC motors —-

• A LinkSprite CuHead WiFi Shield for Arduino $55.0
• An L239D dual H-Bridge $2.0
• A DS1307 Serial Real-Time Clock $3.5
• A 0.5W 8Ohm Speaker $2.0
• A 32.768 kHz Crystal

• Rof various resistors —-
• Transistors $5.0
• Some LEGO components (to make a free-rotating front wheel) —-
• Two LEGO wheels ( main wheels ) —-
• A plastic board (as a base) $5.0
• Two 9v battery (with battery holders) $3.5
• One 3v Lithium Coin Cell battery (with battery holder) $2.0
• One LED( power indicator) —-
• A Koala bear pillow —-

• Total Estimated Cost = 108 //this is the cost of all the parts on the final robot, not including parts used/damaged during the process of building it

.[/vc_column_text][/vc_tab][vc_tab title=”Preparation” tab_id=”1389318510087-2-6″][vc_column_text]

Arduino

• Download Arduino software from http://arduino.cc/en/Main/Software, install drivers
• Look at tutorials from http://www.ladyada.net/learn/arduino/
• Play with some example sketches (File -> Examples -> Choose the sketch you find interesting)

WiFi Shield

• Get WiShield library from https://github.com/linksprite/ZG2100BasedWiFiShield
• Put it under libraries directory and restart arduino IDE
• To use WiServer, ensure that #define APP_WISERVER is uncommented in apps-conf.h
• Open SimpleServer sketch (File -> Examples -> WiServer -> SimpleServer)
• Pass the correct parameters to gateway_ip[], subnet_mask[], ssid[] and security type, for WPA/WPA2 encrypted networks, passphrase are needed. On PC, these values can be obtained through cmd -> ipconfig to get ip address, subnet mask and gateway ip
• For local_ip[] (IP address of WiFi Shield), it must not be used by any other device. We tried with two ways:
  • Test with IPs adjacent to the IP address assigned to a laptop/phone using that network. Note: It does not always work.
  • Turn a phone or a laptop to a WiFi hotspot, it is clear which IPs are unused. To set up WiFi hotspot on win7, do the following:
    • run cmd as administrator (click start, enter “cmd”, then Ctrl+Shift+Enter)
    • type in : netsh wlan set hostednetwork mode=allow ssid=<NetworkName> key=<Password>(required security type is WPA2) in cmd
    • go to Control Panel->Network Connections. Find the network that is connected to the internet (e.g LyonNet-Encrypt).
    • right click the network, select “properties”, then click “sharing”.
    • check the box before “allow other network users to connect…”, and choose “Wireless Network Connection 2” in the drop box
    • type in : netsh wlan start hostednetwork in cmd (to end it, change start to stop)
• Compile and upload SimpleServer. In case it does not compile successfully. In all applicable files:
  • Replace #include “wiring.h” with #include “Arduino.h”
  • Replace #include “WProgram.h” with #include “Arduino.h”
  • In WiServer.h, replace virtual void write(uint8_t); to virtual size_t write(uint8_t);
• Once it is uploaded, wait for red LED on WiFi shield to light up
• Check http://<ip address of WiFi shield> to see “Hello World!”

RTC

• Download RTC library from: https://github.com/adafruit/RTClib

[/vc_column_text][/vc_tab][vc_tab title=”Structure of Kowheeli” tab_id=”1389318553259-3-6″][vc_column_text]

Base

• A plastic board forms the base. It has a hole in the center to allow wires from the motors pass through
• Two DC motors are attached at the back
• A free-rotating wheel made from LEGO is attached at the front

Circuit

The bread board holds an H-bridge circuit which controls the direction of current supplied to the motors, a Real Time Clock (RTC) and a speaker.

Motors

• H-Bridge circuit controls the direction of current supplied to the motors
  • Why do we need the H-Bridge?
  • Because DC motors will only reverse the direction of turning when the direction of current flow is reversed.
  • Principle of an H-Bridge:
  • A dual H-bridge Motor Driver integrated circuit is used to achieve this
  • A step by step guide of constructing a circuit to control one motor can be found here: http://itp.nyu.edu/physcomp/Labs/DCMotorControl, which also includes a schematic diagram of L293NE

Alarm

• A Serial Real-Time Clock DS1307 is a computer clock in the form of an integrated circuit
• It is used as a time keeper regardless of whether the arduino board is powered or not as the coin cell battery will power it.
• It uses a crystal oscillator, which uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency to keep track of time
• The RTC circuit can be constructed as follows:

• A speaker is included to produce pre-set tones when the alarm time matches current time.

Put Together

• Completed circuit looks as follows:

• A detailed connections diagram is drawn below using Fritzing, an open-source software that can be downloaded from: http://fritzing.org/download/

• Note: The red LED is used as an indicator to tell whether power is on
• At last, wrap the pillow around the base, insert more cotton if needed

[/vc_column_text][/vc_tab][vc_tab title=”User Interface” tab_id=”1389319014037-4-4″][vc_column_text]

• Users control Kowheeli through a webpage

• To control the movement of the pet, simply click one of the four links (Forward/Backward/Left/Right) once.
  • Note: the action will continue until user clicks Switch, and the user has to click Switch between actions.
• To set alarm, key in the time and press set.
  • Note: the hour input box only accepts values from 0-24, while the minute box only accepts values from 00-59 (has to be double digits)

[/vc_column_text][/vc_tab][vc_tab title=”Code” tab_id=”1389319044490-5-9″][vc_column_text](current version of code can be found in our status report, week 12)

User Interface

• Inside sendMyPage(char* URL) function, WiServer’s print and println functions are used to write out the page content
• The webpage is coded in HTML
  • Tutorials for HTML can be found here: http://www.w3schools.com/html/
  • To create the links and input box as shown in above section’s picture

Wheel Control Links:
<a href=?RUN">Forward: </a> 
Alarm Setting:
WiServer.print("<form action=""><font face=arial><center><b>Set Alarm Time Here: </b></font></center>");
WiServer.print("<br><input type=text name=HOUR /><b>:</b><input type=text name=MINUTE />");
WiServer.print("<input type=submit value=SET /></form>");

• How does the user interface work?
  • When the user clicks any link or presses set button, the URL of the webpage will change.
  • By reading that change in URL, we can determine which link/button the user has clicked, and according to that, different actions will be performed
  • After that, the webpage will return to index page, waiting for the next action by the user

Motor Control

• In setup(), set all H-Bridge pins as outputs.
• To control one motor, in loop():

One Direction:
digitalWrite(motor1Pin, LOW);   // set leg 1 of the H-bridge low
digitalWrite(motor2Pin, HIGH);  // set leg 2 of the H-bridge high
Reversed Direction: 
digitalWrite(motor1Pin, HIGH);  // set leg 1 of the H-bridge high
digitalWrite(motor2Pin, LOW);   // set leg 2 of the H-bridge low

• Similarly, by setting appropriate turning directions for the two motors, direction of movement can be controlled

Alarm Setting

How does alarm work?

• Current time is constantly compared with time kept by RTC
• When the two sets of values (HOUR:MINUTE) match, output of the speaker pin is set HIGH
• Tones will be played for as long as that minute has not passed

Real Time Clock

• include “RTClib.h” and declare RTC_DS1307 RTC;
• In setup()

Serial.begin(57600);
Wire.begin();
RTC.begin();
If it is the first time, you need to set time for RTC using
RTC.adjust(DateTime(__DATE__, __TIME__));
You do not need to reset time for it as long as coin cell battery has not been detached

• in loop(), DateTime now = RTC.now(); can get the current time
• now.hour(), now.minute(), now.second() can also be useful

EEPROM

• EEPROM stands for Electrically Erasable Programmable Read-Only Memory
• Alarm set by the user is stored using EEPROM so that alarm time is kept even if the board is not powered
• To use EEPROM, #include <EEPROM.h>
• To get and to store value:

EEPROM.read(<position>);
EEPROM.write(<position>);
//position(int) is the address of data

Speaker

• tone(pin, frequency, duration) is used to play different notes
• it generates a square wave of the specified frequency (and 50% duty cycle) on a pin

Debugging Tips

• Make sure every switch is turned on
• Make use of Serial.println()and check through Serial monitor to see which lines are executed
• Introduce test LEDs into circuit and add digitalWrite(<LED pinNumber>,HIGH) at appropriate places, by looking at which LEDs light up and which do not, you may get an idea of which part of your code is buggy
• If your sketch behaves unexpectedly, you might have run out of your memory.(“If you run out of SRAM, your program may fail in unexpected ways; it will appear to upload successfully, but not run, or run strangely.”) Solution: store data that you will not modify while program is running in flash memory instead of SRAM; to do this, use the PROGMEM keyword.
• Google your problem
• Ask people in forums, e.g http://arduino.cc/forum/
• Try all random possible solutions you can think of, even if they don’t make sense at that point
• Make sure the connecting wire is attached to the Arduino board when u are uploading the sketch
• Make sure all the parts are as light as possible and when assembling the parts try to place the CG above the wheels
• When RTC behaves strangely , probably the battery is detached from the breadboard, need to reset the time( sometimes / most of the times there is time lag soluion not clear yet)

[/vc_column_text][/vc_tab][vc_tab title=”Future Work” tab_id=”1389319095549-6-8″][vc_column_text]

• Add a wave shield to allow the pet sing nicer songs
• Add different kinds of sensors, e.g ultra-sonic sensors to enable it to avoid obstacles and heat sensors to make it react to petting
• Develop iPhone/Android apps to control Kowheeli through phones
• Develop a special parent-child pet combination so that when the parents of an MHC student pat their parent pet at home, the child pet in the student’s dorm will react (sing/moving around etc).

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