Remote Controlled Wiitar - Revision history

NathanHirsch: /* Results and Reflections */

2010-03-18T18:11:05Z

Results and Reflections

NathanHirsch at 18:03, 18 March 2010

2010-03-18T18:03:40Z

NathanHirsch: /* Code */

2010-03-18T18:01:51Z

Code

Show changes

NathanHirsch: /* Electrical Design */

2010-03-18T17:27:32Z

Electrical Design

NathanHirsch: /* Code */

2010-03-18T17:23:56Z

Code

NathanHirsch: /* Overview */

2010-03-18T17:17:30Z

Overview

NathanHirsch: /* Electrical Design */

2010-03-18T17:16:21Z

Electrical Design

NathanHirsch: /* Team Members */

2010-03-18T16:35:57Z

Team Members

HenryRandolph: /* PIC Code */

2010-03-18T10:37:16Z

PIC Code

HenryRandolph: /* PIC Code */

2010-03-18T10:33:23Z

PIC Code

← Older revision		Revision as of 18:11, 18 March 2010
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	Despite a creating a system that was simpler than intended, our project was very successful. At the beginning of the quarter, we had ~~limited~~ knowledge of electronic circuitry, no knowledge of microcontrollers, and ~~almost~~ no experience programming in C. Using knowledge that we gained throughout the quarter, we were able to design and build a system that was fun for anyone to use and could control a guitar using a Wii Remote.		Despite a creating a system that was simpler than intended, our project was very successful. At the beginning of the quarter, we had some knowledge of electronic circuitry, almost no knowledge of microcontrollers, and no experience programming in C. Using knowledge that we gained throughout the quarter, we were able to design and build a system that was fun for anyone to use and could control a guitar using a Wii Remote.


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	~~There~~ was also ~~talk~~ of ~~adding~~ a "player piano" mode to our system. This mode would have had the PIC automatically play a song using timed strums and chord changes without input from a Wii Remote. Due to a number of other issues we were having with our project, we did not have time to add the player piano mode. This would have been a great addition to the system that could have really demonstrated its capabilities.		It was also suggested that we add a "player piano" mode to our system. This mode would have had the PIC automatically play a song using timed strums and chord changes without input from a Wii Remote. Due to a number of other issues we were having with our project, we did not have time to add the player piano mode. This would have been a great addition to the system that could have really demonstrated its capabilities.

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 == Mechanical Design ==
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 The solenoids were originally attached to bridge using nuts and bolts. Though this worked, it was difficult to attach the solenoids precisely enough to accurately depress the guitar strings. In the final design, Velcro was used instead of nuts and bolts. This allowed for more precise mounting of the solenoids on the solenoid bridge and facilitated easy reconfiguration of the solenoids into different chord shapes. A second solenoid bridge was added in the final design to allow additional notes to be fretted near the body of the guitar.
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 ==== Strumming Bridge ====
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 A hall effect sensor was mounted about six inches from the motor on the strumming bridge. A magnet was attached to the strummer that aligned with the hall effect sensor when the strummer was parallel to the ground. When these components were aligned, the hall effect sensor sent signals to the PIC, providing feedback on the position of the strummer.
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 == Electrical Design ==
 The circuity used to control the Wiitar is relatively simple.  The figure to the right shows the basic concept of our project.  The Wiimote communicates with a laptop via Bluetooth.  When a user shakes the Wiimote or presses a button on the Wiimote, a signal is sent to the computer.  The computer then sends a message to the PIC via RS 232.  The PIC takes those signals and outputs voltages to control the solenoids or strum the guitar, depending on the signal from the Wiimote.
 ====Parts List====
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 *Wiimote
 *Computer with Bluetooth
 ====Motor Circuit====
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 The H-Bridge we used to drive the motor was an L293D.  It's data sheet can be found [http://focus.ti.com/lit/ds/symlink/l293d.pdf here]
 ====Hall Effect Sensor Circuit====
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 We used the comparator to compare the voltage coming from the hall sensor against some variable threshold which we set.  The inverting input of the comparator was connected to the output of the hall sensor and the noninverting input was connected to a 10 KΩ potentiometer.  By playing with the resistance of the potentiometer, we were able to set the comparator to the correct sensitivity level.  A pull up resistor was connected to the output so that the comparator had sensible outputs.  That is, we wanted the comparator to output HIGH when the LED was on (and thus when the magnet was near the hall sensor) and not the other way around.
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 ====Solenoid Circuit====
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  Note: When assembling these circuits it is important to keep a common ground with the PIC. Without a common ground, the PIC may confuse digital HIGH LOW signals.
 == Code ==
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 The other set of code used is downloaded directly on to the PIC using MPLAB.  To learn more about the use of this program see the [[Getting Started with PIC32]] page.  The code downloaded to the PIC recieves signals from the computer and outputs digital signals and a PWM signal to control the actuators on the guitar.
 ====Overview====
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 *The computer recognizes this event and sends a character to the PIC via RS232
 *The PIC receives the signal and either activates digital outputs or the PWM signal.
 ====Notes about Wiiuse====
 The code used to talk to the Wii was downloaded and modified from www.wiiuse.net.  The download section includes the wiiuse.h header file, a custom header file that formats all the outputs from the wiimote and includes easy to use functions.  This can be downloaded [http://sourceforge.net/projects/wiiuse/files/ here].  Included in the zip file are the header file, and a few .dll files.  These dynamic link library files allow the code to interact with Windows, but can prevent wiiuse from operating correctly on UNIX systems.  Code::Blocks makes it easy to link these files to a project.  Once a new project has been created, go to Project-->build options.  A dialog box will appear and click on the Linker Settings tab.  There is a link libraries window.  Click the add button and direct the program to look where the .dll files are.  When the program asks if you want to add it as a relative path, click No.  The .dll file should be linked to the project.
 ====Computer Code====
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 *LPDWORD lpNumberOfBytesWritten: A pointer to the variable that receives the number of bytes written when using a synchronous hFile parameter.  In our case it's just "&bytes_written"
 *The rest of the parameters are just NULL because they aren't used.
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 This IF loop brakes the motor after the hall sensor is tripped.  The set up of our strummer has the strummer end up in roughly the same place every time.  The weight of the strummer is unbalanced due to the magnet at one end and thus after the motor brakes, it settles down to approximately the same place.
 ====To Sum Up====
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 *The PIC reads the UART port and depending on what the character is, sets particular pins HIGH or LOW
 *Moving the wiimote in a strumming fashion simulates a guitar because the PIC only reacts to some of the accelerometer data it receives
 == Results and Reflections ==

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 Our Wiitar used 6 solenoids and thus this circuit was produced 6 times on our protoboard.
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+ Note: When assembling these circuits it is important to keep a common ground with the PIC. Without a common ground, the PIC may confuse digital HIGH LOW signals.
 == Code ==

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 == Code ==
-There are two separate codes for the Wiitar.  One code runs on the laptop and is the interface between the wiimote and the PIC.  The IDE we use was Code::Blocks.  It's open source, multi-platform and very easy to learn.  It can be downloaded [http://www.codeblocks.org/downloads here].  This code connects the wiimote to the laptop.  Remember that the computer code will only work if there is bluetooth present on the laptop.  If the laptop does not have built in bluetooth, a bluetooth dongle may be used instead.
+There are two separate sets of code for the Wiitar.  One set runs on the laptop and is the interface between the wiimote and the PIC.  The IDE we used was Code::Blocks.  It's open source, multi-platform and very easy to learn.  It can be downloaded [http://www.codeblocks.org/downloads here].  This code connects the wiimote to the laptop.  Remember that the computer code will only work if there is a bluetooth stack present on the laptop.  If the laptop does not have built in bluetooth, a bluetooth dongle may be used instead.
 ====Overview====
 The code used for the Wiitar is relatively simple.  The wiimote talks to the computer through [[Media:Main_wiiuse.c|wiiuse.c]].  The computer then talks to the PIC using [[Media:Main_transmit.c|transmit.c]].  The transmit code runs on the PIC and the wiiuse code runs on the PC.  The structure of the code is as follows:

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 [[image:Wiitar Overview Graphic.png|thumb|400px|Overview Graphic|right]]
-The goal of our project was to create a system that allows a user to use a remote control to play a guitar. The Remote Controlled Wiitar uses a Nintendo Wii Remote to control an array of solenoids and a motor that are capable of playing several different chords on a guitar.
+The goal of our project was to create a system that allows a user to use a remote control to play a guitar. The Remote Controlled Wiitar uses a Nintendo Wii Remote to control an array of solenoids and a motor that are capable of playing several different chords on a guitar.  A video of our project can be found [http://www.youtube.com/watch?v=67hausJ2xZ0 here].
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 == Electrical Design ==
-The circuity used to control the Wiitar is relatively simple.  The figure to the right shows the basic concept of our project.  The Wiimote communicates with a laptop via Bluetooth.  Whenever a user shakes the Wiimote or presses a button on the Wiimote, a signal is sent to the computer.  The computer then sends a message to the PIC via RS 232.  The PIC takes those signals and outputs voltages to control the solenoids or strum the guitar, depending on the signal from the Wiimote.
+The circuity used to control the Wiitar is relatively simple.  The figure to the right shows the basic concept of our project.  The Wiimote communicates with a laptop via Bluetooth.  When a user shakes the Wiimote or presses a button on the Wiimote, a signal is sent to the computer.  The computer then sends a message to the PIC via RS 232.  The PIC takes those signals and outputs voltages to control the solenoids or strum the guitar, depending on the signal from the Wiimote.
 ====Parts List====
-Fortunately, not very many electrical components are required to build the necessary circuitry to control the Wiitar.  The parts that are needed can all be found in the mechatronics lab.
+Here are the electrical components required to build the circuitry used to control the Wiitar.  The parts that are needed can all be found in the mechatronics lab.
 They are:
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 ====Motor Circuit====
 [[image:Wiitar Motor Control Circuit.png|thumb|300px|Circuit Used To Drive Motor|right]]
-The motor that drive the strummer is operated by the PIC.  The circuit to the right gives pin-outs and shows how to connect the motor to the PIC.  Three pins on the PIC are used.  A direction pin, an enable pin and a pin for PWM.  The following table shows how they are related
+The 6W Maxon motor with 6:1 gearhead that drives the strummer is operated by the PIC.  Details on this motor can be found on the [[Actuators Available in the Mechatronics Lab]] page. The circuit to the right gives pin-outs and shows how to connect the motor to the PIC.  Three pins on the PIC are used.  A direction pin, an enable pin and a pin for PWM.  The following table shows how they are related
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 ====Hall Effect Sensor Circuit====
-We used a hall effect sensor to monitor the position of the strummer.  The concept behind a hall effect sensor is simple: it's a device that senses a change in magnetic fields.  So, if a magnet is waved across the sensor, it outputs varying voltages.  We put a pill magnet on one end of the strummer bar so when the motor spun, the hall effect sensor could detect the bar's rotation.  The hall effect sensor basically acted like an ultra-low encoder, but worked for our purposes.  The hall effect sensor was an A2340LUA-T which is stocked in the mechatronics lab.  Its data sheet can be found [http://www.allegromicro.com/en/Products/Part_Numbers/3240/3240.pdf here].
+We used a hall effect sensor to monitor the position of the strummer.  The concept behind a hall effect sensor is simple: it's a device that senses a change in magnetic fields.  So, if a magnet is waved across the sensor, it outputs varying voltages.  We put a pill magnet on one end of the strummer bar so when the motor spun, the hall effect sensor could detect the bar's rotation.  The hall effect sensor basically acted like an ultra-low resolution encoder, but worked for our purposes.  The hall effect sensor was an A2340LUA-T which is stocked in the mechatronics lab.  Its data sheet can be found [http://www.allegromicro.com/en/Products/Part_Numbers/3240/3240.pdf here].
 [[image:Wiitar hall effect sensor.png|thumb|300px|Hall Effect Sensor Circuit|right]]
-The graphic at the right illustrates the circuit we used to hook up the hall sensor.  There is an LED and 1 KΩ in the hall sensor portion of the circuit.  This is just used as feedback.  When a magnet is in the vicinity of the sensor, the light will turn on.  If that doesn't happen, then the circuit is wired incorrectly.
+The graphic at the right illustrates the circuit we used for the hall sensor.  There is an LED and 1 KΩ in the hall sensor portion of the circuit.  This is just for user feedback.  When a magnet is in the vicinity of the sensor, the light will turn on.  If that doesn't happen, then the circuit is wired incorrectly.
-The circuit outputs HI when the hall sensor is engaged and LOW when not.  However, a hall effect sensor is an analog device.  We needed it to output either high or low and not voltages in between.  To solve this problem, we used a LM311D voltage comparator.  This chip is basically a really fancy op-amp.  It's data sheet can be downloaded [http://www.datasheetcatalog.org/datasheet2/c/0hk0a528fi1yzjwj5rxkj21i4wwy.pdf here].
+The circuit outputs HIGH when the hall sensor is engaged and LOW when not.  However, a hall effect sensor is an analog device.  We needed it to output either high or low and not voltages in between.  To solve this problem, we used a LM311D voltage comparator.  This chip is basically a really fancy op-amp.  It's data sheet can be downloaded [http://www.datasheetcatalog.org/datasheet2/c/0hk0a528fi1yzjwj5rxkj21i4wwy.pdf here].
-We used the comparator to compare the voltage coming from the hall sensor against some variable threshold which we set.  The inverting input of the comparator was connected to the output of the hall sensor and the noninverting input was connected to a 10 KΩ potentiometer.  By playing with the resistance of the potentiometer, we were able to set the comparator to the correct sensitivity level.  A pull up resistor was connected to the output so that the comparator had sensible outputs.  That is, we wanted the comparator to output HI when the LED was on (and thus when the magnet was near the hall sensor) and not the other way around.
+We used the comparator to compare the voltage coming from the hall sensor against some variable threshold which we set.  The inverting input of the comparator was connected to the output of the hall sensor and the noninverting input was connected to a 10 KΩ potentiometer.  By playing with the resistance of the potentiometer, we were able to set the comparator to the correct sensitivity level.  A pull up resistor was connected to the output so that the comparator had sensible outputs.  That is, we wanted the comparator to output HIGH when the LED was on (and thus when the magnet was near the hall sensor) and not the other way around.
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 ====Solenoid Circuit====
 [[image:Wiitar transistor circuit.png|thumb|300px|Circuit to drive Solenoids|right]]
-All the solenoids we used on the Wiitar are stocked in the mechatronics lab.  These solenoids are rated at +12 volts.  The power supply in our mechatronics kit could supply that voltage, but the PIC could not output enough current to drive the solenoids with enough force.  To overcome this, we used an NPN Darlington Pair transistor.  The part number is 2N6045 and its data sheet can be downloaded [http://pdf1.alldatasheet.com/datasheet-pdf/view/11497/ONSEMI/2N6045.html here].
+All the solenoids we used on the Wiitar are stocked in the mechatronics lab.  These solenoids are rated at +12 volts.  The power supply in our mechatronics kit could supply that voltage, but the PIC could not output enough current to drive the solenoids with force required to press the guitar strings.  To overcome this, we used an NPN Darlington Pair transistor.  The part number is 2N6045 and its data sheet can be downloaded [http://pdf1.alldatasheet.com/datasheet-pdf/view/11497/ONSEMI/2N6045.html here].
-The circuit we used can be seen at the right.  Using the transistor to increase the current through the solenoid, we were able to successfully drive the solenoids with the PIC.  The output from the PIC was connected to the base of the transistor.  The solenoid was connected between power and the collector.  The emitter was grouned.  There is a 100 Ω resistor between the PIC and the base of the transistor to produce a voltage potential.  We used a 100 Ω resistor because we wanted as much current to go into the base as possible.  By Ohm's Law, the lower the resistance, the more current we could get into the base.  More current into the base means more current through the solenoid and thus more force by the solenoid.
+The circuit we used can be seen at the right.  Using the transistor to increase the current through the solenoid, we were able to successfully drive the solenoids with the PIC.  The output from the PIC was connected to the base of the transistor.  The solenoid was connected between power and the collector.  The emitter was grouned.  There is a 100 Ω resistor between the PIC and the base of the transistor to produce a voltage potential.  We used a 100 Ω resistor because we wanted as much current to go into the base as possible.  More current into the base means more current through the solenoid and thus more force produced by the solenoid.
-An important note is the suck up diode in parallel with the solenoid.  Remember, a solenoid is basically like an inductor.  When the voltage is shut off, the inductor still wants to emit current.  To prevent the transistor from being on, even after the PIC was outputting a LOW signal, a 1N4003 diode was placed in parallel with the solenoid.
+An important note is the suppression diode in parallel with the solenoid.  Remember, a solenoid is basically like an inductor.  When the voltage is shut off, the inductor still wants to emit current.  To prevent the transistor from being on, even after the PIC was outputting a LOW signal, a 1N4003 diode was placed in parallel with the solenoid.
 Our Wiitar used 6 solenoids and thus this circuit was produced 6 times on our protoboard.

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 ==== Team Members ====
+[[Image:team15_thumbs_up.jpeg|thumb|200px|Nathan Hirsch (left) and George Randolph (right)|right]]
 *Nathan Hirsch - Mechanical Engineering - Class of 2010
 *George Randolph - Mechanical Engineering - Class of 2010
-[[Image:Nathan Hirsch.Team15.2010.jpeg|thumb|100px|Nathan Hirsch|right]][[Image:George Randolph.jpg|thumb|100px|George Randolph|left]]
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 One minor detail to the code involves the strummer.  The computer is monitoring the wiimote all the time, so when the accelerometer is engaged data is constantly being streamed to the PIC.  When the user brings the wiimote into the "strumming zone" lots and lots of characters are sent to the PIC.  We don't want this.  We only want the PIC to react after the first "S" is sent.  To solve this problem we use a dummy variable, aptly called "dummy."  This variable is initially set at 1.  When the first "S" is sent to the PIC, the IF loop corresponding to character "S" is executed.  But note that "dummy" is set to 2.  Only when the user brings the wiimote back to horizontal does the dummy variable get rest back to 1 (the IF branch that corresponds to this is the one with IF data = 'T').  Thus moving the wiimote like you would strum an actual guitar translates to the strummer only playing intermittently, simulating a guitar.  This was tested pretty rigorously and seemed to work pretty well, though sometimes the "T" wouldn't get sent and thus the strummer would not strum.
-For reasons not know, the Delayms() function built into LCD.h did not work with our code.  Thus we made our own.  This delay function counts NOPs instead of using a dummy counter variable.  The code for this can be seen below.
+For reasons not known, the Delayms() function (included in LCD.h) did not work with our code.  Thus we made our own.  This delay function counts NOPs instead of using a dummy counter variable.  The code for this can be seen below.
  //********************** Counts "Nops" so that we can use them as a delay function, instead of the Delayms function built into "LCD.h".