Laser harp.

Hey, so I'm pretty new to Arduino, and this is my first project. This should've been my first post, but I already posted questions about this project (with the same main bulk of the post) in other forum subsets. A long time ago I was shown a YouTube video of this guy who had made a "laser harp" where if you broke the stream of a laser with your hand, it would register that and make a sound. I want to supersize this project, making essentially a table (imagine a hollow coffee table with lasers running through it) of 64 lasers and sensors. (It came to that happy number because, since I am a pianist, I decided to make the "strings" 3/4 inch apart, and the table 4' long) So far, I don't have any hardware, but I have these sources: Using LEDs for light sensing http://playground.arduino.cc//Learning/LEDSensor Laser module: http://lightake.com/detail.do/sku.Arduino_5V_650nm_PCB_Laser_Diode_Module___Black-58601?gclid=CLLGvfvO37UCFa9aMgod9wMAIw LEDs to be used as sensors http://lightake.com/detail.do/sku.Arduino_3MM_Red___Green_Color_LED_Common_Cathode_Module___Black-58598 MIDI: http://arduino.cc/en/Tutorial/Midi and Audio output http://www.instructables.com/id/Arduino-Audio-Output/

I have already have pretty extensive knowledge of the ROBOTC programming knowledge which I plan to use to progam this project from VEX (Woo! 6252 The Surge!), so I don't think I'll be needing any help with that, just hardware. I am also currently in a Computer Applications class where we are briefly touching on Arduino, so I can use that as a resource for early testing and such, and learning basic hardware and such. I also know some circuitry from one of my other classes. Hoping you guys can help me out with starting this project as soon as VEX season gives me a little time to do it. Thanks, James D.

I would recommend that you do not use an LED as a light sensor it is more of a novelty than anything else. Use a proper photo transistor.

I think you might be biting off more than you can chew as a first project, just start with a single string.

Yeah, I was planning on making the concept first, one string, then 8, then the full thing etc. and the only reason I meant to use the LEDs was price, and I couldn't find another way to do it... Could you link me to this photo transistor you speak of? EDIT: Someone already showed me a good photo-sensor on a different thread

There is not one photo transistor but lots and lots of them. Just google for one.

Are you thinking of a MIDI output?

MIDI through a PC or chip?

I can’t imagine running a wave table on an UNO but sort of hoping it’s possible.

The best sensors to use for a laser harp build are TSL12S-LF Light to Voltage converter from TAOS, you would need 3 and a dual opamp IC..

Ive built a laser harp and those sensors work perfectly...

I can't imagine running a wave table on an UNO but sort of hoping it's possible.

Sure it's possible that is how this project of mine works:- http://vimeo.com/38466551

Yes, I would also like to see if I can do MIDI output. Not sure how, though I did find a tutorial for it on the playground. And Grumpy_Mike (it's weird referring to people by usernames...) how did do a wave table? Sounds like what I's want to do.

I used an iPad running OSC to control a processing application. This allowed me to define a set of envelopes for each harmonic. This was then converted into a wave table and downloaded into the arduino where it was stored in external EEPROM on the I2C bus. When a wave table was required the arduino picked out one of the previously downloaded ones and transferred it to External SRAM on the SPI bus. This was read under an interrupt and transferred to an external D/A on the SPI bus.

How big were your wave table samples?

Some AVR's can extend SRAM to direct addressable 64k through pins.

How big were your wave table samples?

Each wave table had 16 waves in it, each one being 256 words that is 16 bits wide.

I have everything needed to build a laser harp, i just cant get the TTL modulation to blank to show just the dots without the centre line…

I have the impression that the actual way a "laser harp" is implemented, is that you use a single dimension scanner as in a laser "light show" to generate the individual "strings" from a single laser; the light sensor simply detects from the sequence which string or strings are being played, and issues MIDI commands to a synthesiser accordingly.

In other words, it is not a set of modulated beams with the various frequencies.

cliveharper:
I have everything needed to build a laser harp, i just cant get the TTL modulation to blank to show just the dots without the centre line…

Not sure I understand that.cair to post a schematic?

Nope the schematics are private... Brought and paid for.. Just need advice on how to get the TTL modulation to work, harp builders will know what i mean... :P

harp builders will know what i mean

Good luck on finding one.

Most people here support open source.

Laser Harp hardware == a set of light-interrupt buttons. Nothing more. The software is where "the magic" that plays the music and interfaces with the user resides. It's "magic" because the input is adjusted to fit the song, you need zero talent to play one which probably helps loads with the listening.

Grumpy_Mike:

harp builders will know what i mean

Good luck on finding one.

Most people here support open source.

Yeah.

As I said.