Saturday, March 8, 2014





This past Tuesday, we completed the circuit assembly that converts the digital position signals sourced from our Arduino into dual analog voltages (+/- 5V) from the drawing pictured top middle to the 3x5 inch perf-board. These analog voltages are then fed into the galvanometer controller board, consequently driving the mirror's position steps required for creating the beam fan. On the bottom right the finished circuit board is pictured. The included components (from left to right) are as follows: 3-wire cable harness connection to galvo controller board, Arduino signal interface 4-pin Euro connector, two op-amps (in black/blue) with paired trimpots, 3-pin Euro connector for +/- 15VDC power rails, MCP4725 Digital-to-Analog Convertor (DAC). On the botoom right a view of the underside of the circuit board showing the connections made in between components of the board. 



Tuesday, February 11, 2014


I have moved on for now from testing the various components of my harp and begun the process of packaging the components. Pictured above is the rough layout of the different pieces and their power sources. I was able to arrange the components in such a way that they fit in the given space of the box. On the left is a power strip that the multiple power sources plug into. In the top left corner, the board is cut to make room for the fan that is going to be installed for cooling. The perforated circuit board in the top right will be populated with the circuit components that produce dual + ~ - 5 VDC signals required to drive the galvanometer's controller board.  The board below that is the Arduino. To the left of both of these boards are the relays that will be used to turn the laser power source on/off and drive some indicator lights together with the foot switches for my laser harp. The silver box with holes is the power supply for the galvanometer controller board, which is the component directly above the silver box.

The black wood board pictured in a previous blog will act as a shelf, covering this bottom layer of components. On top of that shelf, the galvanometer and laser source will be mounted.

Tuesday, January 28, 2014




This is the case that will package all of my laser harp components. The board rests on an inner ledge and is what will enclose the wiring. The galvo mirror, laser source, and photo sensor(s) will be mounted on top of the board. I spray-painted the wood board black to make it match the case. 

Friday, January 24, 2014


Today I soldered the header pins to the sockets of the MCP4725 Digital to Analog Converter (DAC) board. This board will generate analog drive signals in the range of 0-5 VDC from digital signals sent to it over a I2C communication link from the microcontroller board. The drive signals will further be fed to a bipolar amplifier circuit, serving as the final set of signals controlling the position of the galvonometer mirror. As a reminder, the galvonometer mirror is what creates the fan of beams from the original single laser source.

Thursday, January 23, 2014




Today, we tested our Arduino microcontroller to see how the user interface worked on the computer. I watched a tutorial that explained some of the basics to writing the necessary code for relating the inputs and outputs of your Arduino board. I wrote a simple code that turned one of the Arduino's embedded LEDs on and off. Easy, I know, but this was the first code I had ever written so it was exciting!


Thursday, January 16, 2014



Galvanometer in from Holland as pictured above. (Item that laser source is pointing into)

Things we tested with the galvo:
- maximum deflection angle
- maximum fan anlge
- voltage necessary to achieve desired fan width
- possible approaches to create equally +/- voltage


Monday, December 16, 2013

Report Rough Draft


Laser Harp Senior Project
Eila Motley
2013-2014
**ROUGH DRAFT**

















Abstract
         I am a member of Stratford High School’s Academy of Science and Engineering. In this program, we are required to work in teams to conceptualize ideas, build prototypes, engineer solutions to everyday and worldly problems, and to practice and develop other skills needed to work in the engineering, science, or medical field. Now that our class’s senior year is approaching, our next assignment is to carry out a yearlong senior project. As an active member of this group during 2012-2013, I believe I am qualified to take on the project of building a laser harp. Although it will be most difficult project I have worked on yet, I will use time management and the resources available to me to make sure that it is accomplished by the spring of 2014.
         A laser harp is an electronic instrument consisting of several beams, that when blocked, produce sound (like the plucking of harp strings). Two different people claim to have invented the laser harp - Geoffrey Rose and Bernard Szajner. Both received patents in the late 20th century. The laser harp then stepped into the spotlight (literally) when Jean Michel Jarre began implementing this virtual instrument in his concerts, beginning with The Concerts in China tour (1981). French engineer, Denis Carnus, who worked a lot with Bernard Szajner, built the harp used for this concert series. The laser harp continued to gain fame, and other variations on the idea have since been developed.
         Building this harp would be a learning experience and a cool way to expand my knowledge on what it takes to put a functioning virtual instrument like this together. My objective is to build a fully functioning laser harp and I plan on using a building method known as “infinite beam” which involves a single beam, a beam splitter, and a synthesizer or computer along with other lesser components.
         My overall objective is to build and be able to play a laser harp. I will achieve this goal by first, acquiring all of the separate components and equipment needed to construct the harp. Then I will use resources found online, as well guidance from my dad, to help me correctly put together the electronic parts of the laser harp. After this, I will work on perfecting the packaging of the laser harp so that it is clean, durable, and easy to transport. I will then use a computer in place of a synthesizer to produce the notes that correspond to the harp “strings”. Finally, I will implement my piano skills and practice actually playing the laser harp until I am able to play it with ease.
        
The estimate cost of my project will be as following:
·      Assembly Needs - $75
·      Powering Needs - $15
·      Programming and Audio Needs - $65
·      Laser Component Needs - $200
This puts the total budget at $355.

**To be added: (3) results obtained, (4) significance of results**

Introduction
         Background: A laser harp is an electronic instrument consisting of several beams, that when blocked, produce sound (like the plucking of harp strings). Two different people claim to have invented the laser harp - Geoffrey Rose and Bernard Szajner. Both received patents in the late 20th century. The laser harp then stepped into the spotlight (literally) when Jean Michel Jarre began implementing this virtual instrument in his concerts, beginning with The Concerts in China tour (1981). French engineer, Denis Carnus, who worked a lot with Bernard Szajner, built the harp used for this concert series. The laser harp continued to gain fame, and other variations on the idea have since been developed.
         Inspiration: I have played the piano for 11 years now and have been musically involved all my life. After seeing multiple videos of Jean Michel Jarre, hearing of my parents' own experience at one of his concerts, and reading further on the engineering behind this modern instrument, I have decided that I would love to build my own laser harp and experiment with the programming of the tones and the actual playing of the beams. This would be a learning experience and a cool way to expand my knowledge on what it takes to put a functioning virtual instrument like this together. My objective is to build a fully functioning laser harp and I plan on using a building method known as “infinite beam” which involves a single beam, a beam splitter, and a synthesizer or computer along with other lesser components.
         I am a member of Stratford High School’s Academy of Science and Engineering. In this program, we are required to work in teams to conceptualize ideas, build prototypes, engineer solutions to everyday and worldly problems, and to practice and develop other skills needed to work in the engineering, science, or medical field. As an active member of this group during 2012-2013, I believe I am qualified to take on this project of building a laser harp. Although it will be most difficult project I have worked on yet, I will use time management and the resources available to me to make sure that it is accomplished by the spring of 2014.

**To be added: “results and conclusions of previously published studies [projects]”**


Methods
  1. Draw a one-line diagram of the system’s key components and their interconnections
  2. Using the drawing from 1., generate a bill of materials for required components
  3. Perform an inventory of items on hand
  4. Purchase items needed that aren’t already available
  5. Set up a blog on blogster.com
  6. Once all required items are gathered, begin construction of following subassemblies:
  • Laser light source and power supply
  • Laser beam splitter
  • Photo-transistor light sensors
  • Interconnection wiring and packaging
  1. Power up laser and utilizing the splitter, split the main laser into eight separate beams
  2. Mount photo-transistor assemblies with proper orientation to be in alignment with the eight beams
  3. Install synthesizer software on the laptop computer
  4. Route the signal from each photo-transistor to laptop
  5.  With the computer and all other subassemblies powered on, begin experimenting with reflection of the beams and the associated sounds produced, modulating the pitch and tone.
  6.  Continue to practice with harp until an optimized musical quality can be produces consistently and harp is a complete musical instrument.

Results
**To be added: Results – once complete**

Discussions
         The success of my project will be measurable by any human ear. If I am to achieve this goal, the end product will be a fully functioning and playable laser harp. If it successful, you will be able to hear it and distinguish a melody being played from it. All of the information regarding my project will be reported in a final presentation of my work in May of 2014. The actual process of the objectives states previously and the current state of my progress week-to-week will be viewable on an online bog, open to the public.

Budget Analysis (original vs. final)
Assembly Needs: Items such as a soldering gun, wire strippers, and pliers will be needed to assemble the components of the laser harp. These components include photo sensors, a circuit board, and MIDI connectors. Assembly materials to construct the final packaging container will also be needed such as sheet metal and paint.
Powering Needs: A 120VAC to 12VDC power supply will be needed to run the laser harp
Programming and Audio Needs: MIDI computer software, a laptop computer to run this software on, an audio power amplifier, and a musical speaker are all needed to program the laser harp and required to produce the sound.
Laser Component Needs: A high intensity green laser beam is a key purchase along with a laser beam splitter that will split the initial beam into the separate “cords”
Performing Needs: In order to play the finished laser harp, I will need to purchase high reflectivity gloves in white for optimal recognition by the laser beams. Also, protective goggles are necessary to play the laser harp as a safety precaution.

**To be added: Further discussion once final results are obtained**

Works Cited






**To be added: most likely additional works cited by the time the final draft is done**