We are a generation that love sound and light – can’t do without them really. Our most preferred time of day is night, or what we would call evening. We are particularly well acquainted with technology; doesn’t hurt these days. Our prerequisite for everything is that it be ‘cool’. Put it all together and in a stroke of brilliance, and a little help from our friend the internet, we have the ideal solution – a laser harp.

A laser harp, what on earth is that? Sounds kind of fancy doesn’t it? Well, it is basically what it says it is. The laser harp is an electronic instrument where a motor, a light sensor, a microprocessor Arduino, and, I’m sure you’ve guessed, a laser collaborate to produce beams, each representing a note (we will elaborate for those who care to read on). This harp though doesn’t have a frame: its strings stretch out infinitely into space – we know no boundaries.

Our inspiration was a video we had watched online and found rather fascinating. Apart from the fact that the prospect of creating it without too much expenditure, mental or monetary, was exciting, it seemed a project providing scope for learning in different areas, especially since we wanted to present it as a complete product. Part research, part reverse engineering led us to figure out its functioning. Admittedly, we have not contributed any addition to the original creation, but to achieve it was in itself gratifying. And there’s always room for originality and improvement in the future. 

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For making this laser harp you will require basic soldering skills, and some experience working with the arduino.

Word of caution: Lasers are very harmful for the eyes, make sure you wear appropriate eye protection.

Our Video will be ready in another 12 hours! Do come back and check it out!

Here's the link to the video that inspired us :

Step 1: Overview of the harp

The basic outline of the harp:
A laser beam is shone. A stepper motor with a mirror divides it into nine beams. When one or more of the beams are cut, the light sensor (Light Detecting Resistor, LDR) detects it. According to the corresponding motor positions, it sends signals to the Arduino, which in turn produces the respective notes through a computer or keyboard.

How the beam is created:
A mirror is attached to the motor. The laser beam is directed to the mirror. The motor rotates in steps, hence stepper motor. With every step the motor takes, the position of the mirror changes, deflecting the beam in a different direction every time. The steps take place fast enough for the beams to appear as if they are simultaneously present.

How the harp knows which beam has been cut:
Every beam has a corresponding motor position. When a beam is cut, it reflects onto the sensor, which detects an increase in light intensity. The light sensor then looks for the position of the motor at the instant the beam was cut, and thus identifies the beam in question.
One of my dreams was to have a laser harp. The only thing I need now is to go buy some 2n222 ULN2003 and, uhm my question was: What kind of/ speed/ steps, steper motor can I use? Hacking some old printer or something, any idea will be appreciated :) <br>Thx, and btw, one of the greatest and really simplest instructable for a complicated stuff that everyone could be amazed with :) Keep it up !
<p>People who are scared of ULN2003: There are quite a few &quot;motor shields&quot; for Arduino that are often usable for steppers as long as you can work out the appropriate winding / connections.</p><p>Pushan: Nice project! Simple, neat, effective, elegant, and pretty. Might make one for a weekend project for my geeky 12-yr-old boys :-)</p>
:) <br>The motor ive used is actually salvaged from some old electronics, any kind of stepper will do the job, you might need to modify the code a bit. I would be happy to help, just send me a message.
Well, the problem isn't in the code really, now the problem is that I can't find ULN2003 here... Do you know anything compatible to that maybe? :) <br> <br>also it would be cool if there is a way to get 3 lasers and make em switch colors hahaha just sayin :)
<p>I know this is probably very late, instead of a ULN2003 you can you a stepper driver. Like for example the easyDriver.</p>
I was actually going to rewrite the code to work directly via usb, not through MIDI... Any ideas about that?
<p>I know this is probably very late, but you should look up loopMIDI, it creates a virtual MIDI port and lets you send MIDI over USB.</p>
<p>To be honest, I would LOVE to see you making a Youtube video creating one Laser Harp...it's just 'cause my mind really will have no chance if it is reduced to writing explanation. We are talking about a Laser Harp, it is a complex thing to do, and not everyone has the same talent to make a Laser Harp the easy way like you do. :)</p>
<p>Great Idea! Now that I'm done with college I'll try to make a video to clarify all the questions, and thanks! :)</p>
and, perhaps a positioning picture (where the circuit is, LDR and stuff would be good, cos I'm really planing to do a &quot;Laser Harp Shield&quot; for this one :)
I love how you've managed to simplify the hardware necessary for a laser harp. Well done! Since I already have most of these materials lying about, it looks like a fun project for an idle weekend. <br>I'm also curious how you would go about detecting the height at which a player was cutting the beam in an enhanced version of this instrument-care to share your thoughts? I would love to add that function.
Thank you! I would use an ultrasonic sensor to read the distance of the players hand, which in turn would control the pitch or volume of the midi notes.
Which version of fl studio is used? And can uplease help me with the motor, it isn't working
This is awesome, great instructable!!! If you plan on only using it with the computer, and don't need the midi out jack, couldn't you theoretically use only the arduino, and scrap the usb/midi converter cable? There are loads of arduino projects out there that output midi via the arduino's usb cable (and maybe some software on the computer side too).
You could even make it wireless :) http://www.ladyada.net/make/xbee/midibee.html
Yes, i just checked it out, and it isnt too hard too send MIDI signals over USB! <br>That's a wonderful idea! Thank you!
Great 'ible! I have most of these parts laying around, and have been looking for something to do with some spare laser diodes and steppers. I saw this (or one just like it) on Hack a Day recently, and though 'How cool would it be to make one of these.' Awesome, thanks!
Thank you! Do put up some pics after you are done!
Wow! This is like a visible version of a theremin, and it sounds better, too.
:) That's exactly what i thought i when first saw it!
<p>I have most everything figured out about this project except where the LDR is relative to the laser/stepper combo. Typically a prism would be used to split the beam so the returned beam may be directed to the LDR but I cannot see such a device in any of the photos. </p>
Can somebody show me how to connect the MIDI?<br>It would be good if anybody could make a video of the whole making. :)
<p>Wowww what was that ? its like dream .. go on man.</p>
<p>Hey, so me and some of my classmates are doing a school project for computer science/technology class, and our project is based around creating a laser harp or a similar mechanism. I came across your tutorial, but we have a very limited budget and minimal experience, so we were wondering whether there was an easier way to make a more watered down and more simplistic version of a laser harp type project. We have some budget, speakers, lego mindstorms, and makeymakey circuit boards. Any ideas and/or advice would be much appreciated! Thanks!</p>
<p>Hey, so me and some of my classmates are doing a school project for computer science/technology class, and our project is based around creating a laser harp or a similar mechanism. I came across your tutorial, but we have a very limited budget and minimal experience, so we were wondering whether there was an easier way to make a more watered down and more simplistic version of a laser harp type project. We have some budget, speakers, lego mindstorms, and makeymakey circuit boards. Any ideas and/or advice would be much appreciated! Thanks!</p>
<p>Could you please provide a picture of the position of the light dependant resistor (lDR) i cant make sense of where it goes in relation to the laser beam. I've manages to order all the parts on ebay for under $40 AUD. </p>
<p>How did I not see this 2 years ago? This is awesome, must build.</p>
<p>Nice project! There should be a current limiting resistor into the base of the 2N2222 or you run the risk of damage to the transistor. The gain on this transistor is about 100 and the drive output from the Arduino could be as high as 20ma. This means that if connected wrong the transistor could be expected to sink 2A! At that point it becomes a noise emitting diode! Why not just use one of the unused outputs from the ULN2003?</p>
<p>What stepper motor should I purchase? Is there a particular one? OR what are the specifications that are needed in a stepper motor?</p>
thanks pushan .<br>I did it .It works great. <br>Thank you for your work. <br>It was also really interesting. <br>The fl studio was little bit confused, but managed it.<br>so thanking you again.
<p>Do I need to use a 2N2222 transistor or would any npn transistor work?</p>
<p>Hi, this is a very neat project and I'm thinking of trying it myself, but I would like to know, do you think a 5mW green laser pointer would work fine? I don't know much about lasers except what I just finished googling and I'm nervous about getting one that's too powerful that it could be potentially dangerous so I would love to hear your advice.</p>
5 mW is safe enough I would say, just make sure not to look directly into the source.
Excellent, thank you!
<p>i dont understand the midi section plzzzzz help me </p><p>because i have to submit the project</p>
Hi there, <br>To best understand the midi section i suggest just trying to play a bit with the Midi example file. Upload it, and get it to play notes and then apply that to the harp.
plzzz give the full dicription about the laser harp and also send me the full vedio of laser harp<br>
<p>Has anyone found a cheap MIDI keyboard? It's the most expensive part of this project by far and I was wondering if anyone has found something economical. ~$100 is what I've found so far.</p>
how can I use a 4 wire stepper motor for this laser harp.<br>Please let me know.
Hi Pushan, excellent instructable. Finally getting around to building this. Quick question, in your fritzing diagram you show 6 wire stepper, but in photos you show 5 wire. Also in the photo the wire is taped so colours change to 4 red and one green. This makes it difficult to see which stepper wire goes to which pin on the uln2003 - can you help identify which is which please? Many thanks! :)
<p>I've joined the two ground wires to make one, if you see the number of wires coming out of the motor, there 6. :)</p>
<p>Yipppppiii.................. I made it............ Its 100% Working...... Awesome experience to play with it. My setup has 5mW high bright green laser &amp; stepper motor salvaged from printer. I am also generating music from FL Studio...... :) :) Very soon i will post an instructable on it. I am very very thankful of @Pushan Panda &amp; issac_engel for inspiration behind this.<br></p>
<p>Wow!! great job! I'm honored to be mentioned :)</p>
<p>hey can u send me a video of your laser harp.</p><p>ayush.sharma2571994@gmail.com</p><p>pls</p>
<p>i will try to send as the size is much larger.</p>
Thanks dude GREAT WORK!.Im trying this myself so what is the trimpot used for??
<p>Thanks! the trimpot is used to vary the sensitivity of the LDR light sensor, as the gentleman bellow said.</p>
<p>It looks like it is there to vary the sensitivity of the LDR light sensor. Did you finish this, I'm about to start.</p>
unquestionably THE coolest thing I've EVER SEEN! Great work and awesome 'ible!
:) thanks for that! made my day

About This Instructable


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Bio: I am interested in all aspects of design and technology, I take to pottery in times of uncertainty, it is my grounding. The piano is ... More »
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