Step 2: The Circuit

Everything is contained on a single 3x5" double-sided circuit board. I designed the schematic and PCB in Cadsoft Eagle, but unfortunately the size is above the limits of the free version. You can still view the files, but you can't edit them without at least the student/non-profit Standard edition.

Feel free to experiment with component values, but be aware that some of the values are rather specific, and changing them too much will adversely affect the operation of the circuit, potentially causing damage to components on the board or to devices connected to it.

All of the "external" controls - the ones that are used by the musician on a regular basis - are connected to the board using header connectors. This is optional, but I do recommend it since it makes troubleshooting and assembly easier (or possible, in some places!)

At first I was going to design my own power supply, but then I found a nifty pre-built power supply with exactly the specs I needed. It's a little pricey at $60 but I think it was worth it. Who wants to mess about on something trivial like the power supply? The Prism was designed to run on +15, -15 and +5V, though it may work just fine on +12, -12 and +5V, which means you could use a modified computer power supply. I haven't tried it though, but it certainly wouldn't harm the circuit.
May be the lazer beam can be smaller to were it's easier to play other strings but my question is can you play bass chords on it or power chords
<p>I think this is a truly great project, but one very bad thing about it, it's that it seem very hard to &quot;pluck&quot; the cord you want to without playing the other. It's not instinctive at all. I'm thinking about making one, but first, I have to resolve this issue because, if I don't, it sure this instrument will end in a box somewhere.</p>
This is a great project and I am currently working on a similar one myself. I see that you have actually made some serious improvements to this guitar in this youtube video http://www.youtube.com/watch?v=4CnRsTaShUU <br> <br> I have watched the above video a bunch of times but I can't figure out what kind of sensor you are using to detect which fret you are on, and how it is precise enough to get the 'bending' within the fret. I see four sensors where you currently have the one on the old prism guitar, but it seems much more sensitive than just four IR sensors. <br> <br> My last question is about how the actual guitar sounds, where it is clearly no longer a sine wave/triangle wave/etc. Did you just program each 'note' to an audio file which would play when triggered? Again, great project and I look forward to hearing how you changed the prism guitar.
Very awesome. How are you using the neck to control the pitch? john_a4321 kinda asked the same thing. The way you described it, the range finders control the pitch, however when I watch the video if you playing, it looks like the range finder is just used to &quot;pluck&quot; the &quot;string&quot; and you are using the neck in a more traditional way to actually get different notes out of the string. What is going on here?
what is the sensor of the neck of the guitar <br>
hey........its been along time since ive seen this instructable <br>im still fascinated with it... <br>just to make it simpiler can you remove most of the stuff and put in an arduino?
can i gt the schmatic circuit diagram of the circuit above
It's right there under the text, called &quot;laser guitar.sch.&quot; You will need Cadsoft Eagle to open the file.
Wow, man. You got skillz!
About how much in total, minus the guitar, does this cost to build? i'm interested in making one as a senior project for school. And is there somewhere i can find the parts list?
my bad, i hadn't read the comments far enough<br>
No problem! But you may want to hold off for a week or two. I've got something coming that I think you'll want to build instead!
I totally failed to get my updated guitar ready in time for the Epilog contest. That, and I was busy building a second storey on my house. It's been finished for a while now, though I couldn't find any musicians who were willing to play around with it for more than an hour or two (somewhat disappointed about that, actually). I needed someone to film showing what it can do since I can't play myself.
:/<br>I imagine how frustrating it is.<br>I hope you can find someone to help you so you can upload the instructable.<br><br>I think I'll wait for the next one then. =)
Whats the word on this alternate build?
This is AMAZING!<br><br>I want someone to play &quot;Derezzed&quot; by Daft Punk on this beauty. Or even better, interface it with a solid state tesla coil!!!!!!
I love the project, and i'm not sure if anyone has called you out on this, but it is a bass, not a guitar, 4 strings!!!<br><br>Thats all, i would love to make one though
Well, it was made from an old bass, but what makes it a bass guitar? The length of the neck? The tuning? The number of strings? A tenor guitar only has four strings, yet it is not a bass.<br><br>Really, the Prism can be whatever guitar you need it to be... within the confines of four strings, of course. ;)
well measure for me the scale length (from the two points the strings touched the bridge and nut.) If it is 34 inches, it is a bass, also it should have about 20-24 frets. Tuning does not matter, because you can tune any instrument to achieve any tone you want.<br><br>A bass guitar is just the term for an instrument with all of those qualities, and it is really just a name.<br><br>Please do note however, that you do not play &quot;chords&quot; in the same was as you would for a guitar. A bass is one note plucked at a time, however sometimes one can play the octave of a note at the same time as the original to achieve the correct tone.
One other thing, your &quot;victim&quot; included standard P-Bass pickups in the hum-bucker layout, also a thumb rest below the strings. Both of these are used in basses, not guitars<br>
Well, it definitely used to be a bass. And it used to have frets, and strings, and pickups, and a thumb rest. Is it a bass if all those have been removed? It's kind of in a gray area, I think. As far as sound is concerned, it's more like a synthesizer or theremin...
I was just curious, what exactly do the connectors in the schematic hook up to? I am currently bread boarding this project and have no idea what to connect each of the plugs to.
Most of the connectors are labeled in the schematic and ought to be self-explanatory (but ask me if they aren't!) The trickiest ones are the two switch potentiometers, which have a switch and pot integrated into a single unit. The steps that describe those components may help.<br><br>If you need full-scale drawings or the original schematic, send me a PM with your email address and I'll send them to you.
I meant what do the &quot;jp&quot; plugs in the schematic get plugged into? Specifically jp3, jp4, jp5.
Also, what does the &quot;Thermal Connection&quot; note in the schematic mean?
The two components must be physically touching, preferably with a layer of thermal paste between them.
Ah! Those go to the rotary switch. It switches between sine, square and triangle waveforms. Step 7 has details on how to wire the switch itself.
Is it me or those schema and part list do not work, it ask me witch program I want to use to see it, have an idea guys?
To view the schematic you'll need Cadsoft Eagle, get it at www.Cadsoft.de. Or is your problem that they are downloading as .tmp files? In that case, try renaming the file to what it was supposed to be.
You would destroy such a beuty!!!!!<br><br>Just kidding nice project, might work on a variation as a side project =D
I cant seem to open laserguitar.brd, laserguitar.sch, &amp; prism parts list! Can U help me out?
.brd and .sch are Eagle CAD files; get a free copy of Eagle at www.cadsoft.de. The parts list is .txt, that shouldn't be a problem... Or are you getting .tmp files? Try renaming them as appropriate. If that doesn't work, let me know and I'll email them to you.
Sorry, I still having trouble with these!
Well, describe the trouble and I'll try to help...
Great man!!
How glossy would the paper need to be because im wondering if i am going to need to buy some very glossy paper online?
You shouldn't need to go online to find the paper. Glossy photo paper works well (I use paper marked &quot;high gloss&quot;), others have had success with glossy magazine covers.
does it matter how long after i print it that i actually iron it onto our copper?
I'm not sure. I always did the transfer within hours, to avoid the possibility of scratching the toner off the paper.
using these exact instructions i did this &quot;laser printer and all&quot; and i ended up with a barely transfered ink. this is very strange... are you sure it doesnt need to be an inkjet printer <br>
100% sure it must be a laser printer.<br><br>However, the toner transfer method can be a bit finicky. There are a number of factors that can affect the transfer - the type of toner the laser printer uses, the &quot;darkness&quot; of the toner, the type of paper used, the cleanliness of the copper clad board, the temperature of the iron, the pressure used on the iron, the amount of time the iron was pressed on the board...<br><br>So, I assume that the toner transferred in some places, but not others? Try cleaning the board really well with fine steel wool. That helps the toner &quot;stick&quot; to the copper. Also try different types of paper. Some people have better luck with photo paper, others with glossy magazine paper. Or, you could try the dedicated &quot;blue&quot; toner transfer paper.<br><br>Another thing to watch out for is air bubbles. I think, but have not confirmed, that air pockets can form between the paper and the copper, preventing a good transfer.<br><br>Good luck!
I wonder if I can get the lasers mounted horizontally, rather than vertically. Also, you've probably been asked this multiple times before, but how much do all the parts come to?<br><br>
What do you mean, horizontally? Like, sticking out of the guitar? It's definitely possible, I'm not sure why you'd do it though.<br><br>The parts came to around $300 I guess, though some are now obsolete and hard to find.
Horizontally as in, instead of this:<br><br>|----- &lt; laser<br>|-----<br>|-----<br>|-----<br><br>Like this:<br><br>_._._._._<br> | | | |<br> | | | | &lt; laser
Yeah, that'll work as long as the sensors are lined up with the laser beams.
I understand if it would be too time consuming, but could you tell me what parts are outdated/discontinued? (And if possible, suitable replacements)<br><br>I'd really appreciate it.
SSM2210 (IC10) and the XR2206 (IC1, IC6) will give you trouble. The rest of the parts are either available or have an easy-to-find replacement.
Thankfully, there is one listing for the SSM2210 on ebay (which I am definitely buying tomorrow) and the XR2206 is, surprisingly, sold at Jaycar (Australia's RadioShack, but with a crappier product range :P)<br><br>Thanks for the help, definitely going to post pics when this is finished.
Well, the spaces didn't work in the second bit of ASCII art, but you get the point.

About This Instructable


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Bio: By day, Jeff is the Jack of All Robots at Clearpath Robotics. By night, a mad scientist / hacker / artist / industrial designer wannabe!
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