Laser harp Attemp, Questions about sensors...

jcalvorquin · Unread post by **jcalvorquin** » 21 Jul 2010, 19:58

Hi, this is my first Topic on the Forum. I´ve being using usine for a while and getting allways really amazing results...

At the moment I´m trying to make the most advance device I´ve ever made, wich is basically half MIDI controller half Laser Harp (Midi controller also), the project is really exciting and I have to admit is being really dificult to get all the parts and components without spending a fortune.

I´m using an UMC32 board http://www.halemicro.com/Products/Products.html wich basically allows you to connect potentionmeters and swithces in to the board and trnslate it in to MIDI values.

And the problem comes with this sensor Sharp gp2d12

At the moment I think I have spent 180 euros, not bad at all and everything is working perfectly, 8 knobs with CC, 8 momentary buttons note on/off, and the 8 lasers with 8 light sensors (Light dependent resistors) wich work as on/off buttons when the laser hit the resistor and on when the beam is interrupted.

Great, now I tried to make two distance sensors, one for each hand because I think an amazing feature for the laser harp would be to have CC control on each hand while playing the notes in the laser beams... So I bought two Sharp GP2D12 IR sensors for that purpose, but... It seems that the Sharp sensor gives you non-linear response...

I tryid to find information in how to build a circuit to translate non-linear to linear voltage values but I don´t have enough knowledge about electronicsand everything that I´ve found is formulas and formulas.

Anyway, because I´m using usine to build the patches for that invention, I thought, maybe ther is a formula or variable in Usine that allows me to turn a non linear MIDI value in to a linear value and use the information to control a knob smoothly.

If anyone have any idea or know wich formula can I use to achieve the use of the non-linear parameter, It would be really helpfull...

Thanks in advance.
Julian.

ethnix73 · Unread post by **ethnix73** » 21 Jul 2010, 20:14

Hello,

I do not know the formula, but you could use mapper (value) or (curve) module...

jcalvorquin · Unread post by **jcalvorquin** » 21 Jul 2010, 20:49

ethnix73 wrote:Hello,

I do not know the formula, but you could use mapper (value) or (curve) module...

Thanks... yes when I meant the formula is the patch on usine to use it... Sorry.

Anyway I keep looking for information and making some tests and I´m sure there is a hardware incompatibility or something like this because actually the interface doesnt work when I have the sensor connected.... It becomes crazy, and also it seems that it consumes a lot of mA from the USB, so shit !

I think I will have to use another kind of sensor for the expression...

Thanks anyway... and if someone know how to attempt the circuit conversion, Thanks!

All the best.
Julian.

nay-seven · Unread post by **nay-seven** » 21 Jul 2010, 21:38

not easy to help you on this
have you think about a wiimote ( fixed on your arm ) for the expression, works fine with Usine

Floego · Unread post by **Floego** » 21 Jul 2010, 22:08

Maybe I'm naive but, why don't you convert the laser signals to especific pure tones?

Mixed it up and bring it to usine through the sound input. Once the sound is processed , filtered, etc., you could convert every tone to midi notes, with intensity included. Not as elegant as your original project, but could be very easy to implement, I think?. The sharp sensors seems to respond in a logarithmic way, like our ears do.

jcalvorquin · Unread post by **jcalvorquin** » 21 Jul 2010, 22:17

nay-seven wrote:not easy to help you on this
have you think about a wiimote ( fixed on your arm ) for the expression, works fine with Usine

Thanks!... Well If I´m honest I thought on using the wiimote, as works great as you says, you can even use the Infra red dot´s in your hands and the wiimote as a camera and control it... But the thing is to mix too many inventions in one... Maybe it will be the answer I will post the coments and photos as soon as possible...

I am able to make a shabby distance sensor with photocels (LDR) and a resistor, but the behaviour depends on the light, and sometimes is really hard to control the light environment. Also the laser harp is going to be used in darkness, because of the lasers and the light sensitive sensors doesn´t work as accurate as an Infra red detector in this kind of situation...

Anyway thanks for the help and ideas is really apreciated...

All the best.
Julian.

jcalvorquin · Unread post by **jcalvorquin** » 21 Jul 2010, 22:20

Floego wrote:Maybe I'm naive but, why don't you convert the laser signals to especific pure tones?

Mixed it up and bring it to usine through the sound input. Once the sound is processed , filtered, etc., you could convert every tone to midi notes, with intensity included. Not as elegant as your original project, but could be very easy to implement, I think?. The sharp sensors seems to respond in a logarithmic way, like our ears do.

Thanks floego but I don´t understnad what you mean with convert every tone to midi notes... I have already the way of playing notes with laser, is just CC values for for example pitch bend and modulation, while playing in the air...

Thanks!!!

Floego · Unread post by **Floego** » 21 Jul 2010, 22:58

Oh sorry I didn't express myselft clearly enough.

I was trying to say:

The distance sensors converts distance to voltage.

Then convert voltage to sound: for each sensor, one mono channel. Could be a voltage to frequency conversion, maybe.

Once you have converted to sound, you can put it inside Usine, like a sound module does.

Now, using usine, convert the sound signal to distance again or to anything you want, like midi cc. That is the goodness of usine.

About voltage to freq conversion, I believe there are many chips out there.

It is just and idea, maybe not a solution for what you want.

jcalvorquin · Unread post by **jcalvorquin** » 21 Jul 2010, 23:22

Thanks Floego, It´s sounds good...

The thing is that I spent 12 euros on each sensor and, because they remember me a lot to the D-Beams on my old Roland mc 909, wich are really fun... But being honest and trying to be realistic, I´m going to make the device, just with no expresion control and as soon as I have everything working I will try different systems maybe like a small theremin, photoresistors or even a bend sensor attached in to the hand...

I have a DIY analog theremin and I was able to convert the frequency to CC quiet good with USINE, so maybe I will try to make a reaktive antena somewhere in the device reacting to the proximity of the hands, and translate it to CC´s, sound a little bit easier for me and Free of wires, wich is a good point.

Thanks a lot for the comments...!

All the best.
Julian.

ethnix73 · Unread post by **ethnix73** » 22 Jul 2010, 00:01

I have a DIY analog theremin and I was able to convert the frequency to CC quiet good with USINE

Interesting!
How did you made your theremin?

jcalvorquin · Unread post by **jcalvorquin** » 22 Jul 2010, 00:45

ethnix73 wrote:
I have a DIY analog theremin and I was able to convert the frequency to CC quiet good with USINE
Interesting!
How did you made your theremin?

Hi ethnix73, I´m an enthusiast of theremins...

I firstly made an opto theremin 6 years ago, wich works with photocellls instead of electromagnetic waves, and the funny thing is that I spent like 4 euros to make it, is soooo simple, but it was more a FX machine than a propper theremin, then I Download schematics from "Theremin hispano" I don´t remember exactly but I can try to find them and post them.

The thing is I broke it in a gig and finally I decided to make another one, this time I bought a kit in Australia, the "jaycar kit" I think is called and is about 50 euros, but it comes with everything necesary to make a more propper theremin, you can actually play melodies and it has a accurate controllable range...

Actually making shorter or longer the anthena you get the proper octave range to get silence and good values, and then in usine Just use frecuency to MIDI converter to get the values...

Regards!

Clearscreen · Unread post by **Clearscreen** » 22 Jul 2010, 03:57

I've played around with ultrasound distance sensors before, not IR ones, but with the ultrasound ones I found there was a LOT of hysterisis going on with the input. maybe try the hysterisis modules in usine and see if they reduce/smooth the noise in the input? Hope it helps...

PS - are you still in Australia? I'm in melbourne...

jcalvorquin · Unread post by **jcalvorquin** » 22 Jul 2010, 13:08

Clearscreen wrote:I've played around with ultrasound distance sensors before, not IR ones, but with the ultrasound ones I found there was a LOT of hysterisis going on with the input. maybe try the hysterisis modules in usine and see if they reduce/smooth the noise in the input? Hope it helps...

PS - are you still in Australia? I'm in melbourne...

Hi... No at the moment I´m living in BRighton UK, sorry...

I´m going shopping today to see what I found around, I just saw yesterday night an analog IR sensor that may help me... I´m gonna build it and see wich output gives me...

That´s the idea...

I will post the values this afternoon probably... and maybe some pictures...

All the best and thanks for the help...!!!

All the best...
Julian.

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