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Laser harp plans


camvo

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@ tonyt


I made the first harp like that. 10 laser pointers and 10 LDR-s. with a MIDI controller board.

This type of harp needs a frame to hold the LDR-s.
Each beam has its own detector. To align the fram with the laser pointers was a real headache. It almost drove me insane.

The frame was big and heavy. After heavy complaining from my wife, I disassebled the "STARGATE" and gave up on that principle.

My harp is frameless and fits in a briefcase. Easy to carry, easy to store.
 

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camvo

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Sure no problem.

The left yellow led is the power led.
The blue led means that a beam is touched.
The 2 green led-s on the right are rgb-led-s. They indicate the status of the tone bank and octave.

Further you change midi channel and transpose the keys.

The MIDI cable (top left connection) is not connected here.
 

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Things

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I was contemplating doing a v3 run of my laser harps, but they wouldn't be in kit form, but in a plug and play enclosure with ILDA, ready to go, however I've determined there isn't much of a market for them right now.

A few ideas that could make yours more interesting would be allowing multicoloured beams, however this takes special considerations as your light level into the photosensors is no longer constant. My idea was to use a basic form of a camera, one of a low enough resolution it could be interfaced with an Arduino, and used to track the dots of light on your hand. This would also allow pitch bending, and would handle multiple colours no problem, but the coding would be an absolute nightmare, as you'd have to do both image processing, and be able to output MIDI and the laser data at the same time.

It would probably be better suited to a multi-core microcontroller, but due to lack of interest I haven't really bothered looking into it much.
 
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camvo

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Hi Things,


It has been a whilel since we "spoke".

Basically the main board of harp already has multi color capability.

I just recently received my new 1W RGB unit. I did not have the time to make another main board. But I will do that soon or I will hack my own green harp. :p

My goal with the plans is that every one with a bit of experience in electronics can make this harp.

The advantage of the Boarduino is that it is small, it is easy to incoperate in the system and on a PCB. It is very easy to re-program through its USB connection.

I did not use a display like in your harp. To program the harp on stage would be a nightmare. To keep pressing buttons and staring at a small display would be far from ideal and very time consuming.
I prefer to hook up the harp to a computer and upload new code (which you prepared at home) within 6 seconds.

Perhaps to use a RaspberryPi as central core could do all the things you want??
It even has a sound card onboard. And you can use a much bigger display. :D
 

Things

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Yeah, the display on my harp was basically useless, you couldn't program the harp from it either, it as basically a status indicator. If I did include a screen in the newer versions, it would have been one big enough, possibly witha touchscreen to make that easier.

And yeah, I have considered the raspi, though it'd be a huge project as I've had very little linux programming experience.

The harp hardware wise is quite simple, it's the code that can get tricky fast. It took me a good while to optimize it to run fast enough.

PS: I noticed in your other thread you're trying to get brighter beams. One way I solved this is to have the galvo's "wait" at each beam for a bit longer. Instead of just scanning a line and turning the laser on and off at the right time, have the galvo's actually stop at the point, say for 5ms or something. This is especially helpful with green lasers, as they do take some time to actually start lasing, but also because the human eye is pretty slow, so if the beam isn't there for long, it's apparent brightness will be much lower too.
 
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camvo

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Originally I tried blanking but lost a lot of visibility like you said.

So I did the same. put the mirror at a pause at the beam position.
It gives a far more brighter appearance.

At this moment, the only thing I would like to add to the harp is:

After the beam is released, it vibrates a bit like a guitar string after plucking. :D
 




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