bosone Posted August 10, 2007 Report Share Posted August 10, 2007 after the building of the AC sensorizer i'm wondering how to achieve a sort of ribbon controller...these are my first steps, after searching for thru the net...i used a piece of a common VHS videotape to make the base of the ribbon contrller. its resistivity is a function of length. i tried different brands before finding a good one: several where not conductive on both sides. the right one had only one side conductive.i assembled everything on a piece of hard paper, for now, and i used a "suspended" guitar string to make a contact between the finger and the VHS tape. the string doesnt touch the tape, the contact comes only when i press the finger... this is a little tricky but feasible...the problem is the string tension which maybe will tend to loose... maybe it will be necessary some other method to fix it... for now it's just "tied" to some hard adhesive...i also used some "conductiver tape" to achieve contacts between all the parts.when i apply 0-5 V at the edge of the vhs tape, press the guitar string somewhere in between, i read a varying voltage... exaclty as expected! :-)now i have to think how to fix everything and, moreover, i have to find a way so solder wires... it's not as strightforward as it seems... maybe i will use some little of piece of PCB boards to fix the string, the tape and the wires...DSCF3587.JPG Quote Link to comment Share on other sites More sharing options...
Jaicen Posted August 10, 2007 Report Share Posted August 10, 2007 Looks good, but it's not how i'd do it.I'd have the tape laid flat on cardboard, as you have. Over that, i'd lay a piece of card with a slot cut out of it. The card becomes your spacer. Then i'd find some conductive plastic, such as an antistatic bag you get IC's in. This needs to be glued to the cardboard under slight tension, to prevent it from sagging into the slot. Once the whole thing is constructed, it can be laminated for durability. Quote Link to comment Share on other sites More sharing options...
audiocommander Posted August 10, 2007 Report Share Posted August 10, 2007 looks good;I'd fix everything on a wood plate and maybe I would also think about turning the items; I can imagine it's more comfortly to weep along a SVHS tape than a guitar string? dunno :)Maybe there are more ways to construct this; the gap is surely a tricky mechanical thing. I know of some footswitches / dancemats that work with thin foam layers...Anyway, cool project!Best,MichaelEdit: just because I read somewhere that it's important to use a SVHS tape: you were successful with a normal VHS tape, is that right? that would be cool... Quote Link to comment Share on other sites More sharing options...
bosone Posted August 11, 2007 Author Report Share Posted August 11, 2007 Edit: just because I read somewhere that it's important to use a SVHS tape: you were successful with a normal VHS tape, is that right? that would be cool...yes, i too read about SVHS tapes. mine was a common VHS for commond TV videorecorder... but i had to try several of my "collection" at home in order to find a good one (where "good" means: with the backside of the tape that show some resistivity - in the order of 100koh - most of them were totally insulating...) Quote Link to comment Share on other sites More sharing options...
bosone Posted September 24, 2007 Author Report Share Posted September 24, 2007 finally i completed my project.it seems to work pretty well... but i have to find out a way to avoid flickering at minimum value when i don't press it, the AC Sensorizer reads values between 0 and 60 (out of 127), while the minimum touch is at 30....i think i will try to make a contact so that if i don't press anything it stays at maximum valuelook in my site:http://www.alchemystudio.it/Strumenti/ACSensorizer/ACSensorizer_en.html Quote Link to comment Share on other sites More sharing options...
cimo Posted September 24, 2007 Report Share Posted September 24, 2007 ciao matteo!!very good and inspiring .. i had an idea but it s easy if i try to sketch it up and show than if i try to explain.. ;) SimoneEDIT: will that change anything if something has been recorded in the tape? Quote Link to comment Share on other sites More sharing options...
bosone Posted September 25, 2007 Author Report Share Posted September 25, 2007 i dont think it will change anything if the tape is recorded... also because i'm using the backside of the tape itself.give a look herehttp://www.midibox.org/forum/index.php?topic=8401.msg73154#msg73154where i discuss the flickering problem i have when the circuit is open... Quote Link to comment Share on other sites More sharing options...
DrBunsen Posted September 25, 2007 Report Share Posted September 25, 2007 Nice work!I like the look of Simone's version, but I'd suggest using some soft foam instead of paper. Quote Link to comment Share on other sites More sharing options...
cimo Posted September 25, 2007 Report Share Posted September 25, 2007 mmmm ... foam... it s getting better and better i can t wait to do my own one...there are many kind of tapes we could try, old audio tapes, vhs, svhs, dat (are they tapes right?) old systems for videocameras, probably there is a best choice to go with..another little idea to have the sensor shortened..you could emm matteo in italiano poi vediamo in inglese, allora se prendi tipo una stecca di plastica e ci arrotoli il nastro, intorno e a spirale, quindi partendo da una parte e finendo dall altra.Ci sarebbe quindi piu resistenza per centimetro e si potrebbero fare dei sensori piu corti che ti sembra?ciao! Quote Link to comment Share on other sites More sharing options...
Screaming_Rabbit Posted September 25, 2007 Report Share Posted September 25, 2007 there are many kind of tapes we could try, old audio tapes, vhs, svhs, dat (are they tapes right?) old systems for videocameras, probably there is a best choice to go with..... good old 2"-Multitrack tape. - The carrier tape is nice fat and has some stiffness.Greets, Roger Quote Link to comment Share on other sites More sharing options...
bosone Posted September 25, 2007 Author Report Share Posted September 25, 2007 mmmm ... foam...you could emm matteo in italiano poi vediamo in inglese, allora se prendi tipo una stecca di plastica e ci arrotoli il nastro, intorno e a spirale, quindi partendo da una parte e finendo dall altra.Ci sarebbe quindi piu resistenza per centimetro e si potrebbero fare dei sensori piu corti che ti sembra?se ho capito bene... secondo me non funziona... la resistenza variabile è quella tra i due capi della corda sospesa sopra il nastro. avere un tape lungo un metro ma con una corsa della corda (l'elemento che poi vai a toccare) di 10 cm non cambia le cose...io l'ho fatto lungo per avere più risoluzione e perchè avevo in mente che avere una corsa lunga sia più comodo in fase di utilizzo... un ribbon di 5 cm sinceramente non lo vedo così utile... :-) (ma neanche di un metro!!!) se fai il conto, 127 step in risoluzione MIDI di Control change in 30 cm sono circa 1 step di CC ogni 4 mm, che secondo me non è male e lascia molto margine di azione... Quote Link to comment Share on other sites More sharing options...
cimo Posted September 25, 2007 Report Share Posted September 25, 2007 ciao matteo si sono daccordo pero non tutti hanno a disposizione tutto quello spazio, io almeno non ce l ho..avere un tape lungo un metro ma con una corsa della corda (l'elemento che poi vai a toccare) di 10 cm non cambia le cose...cambia se il nastro non tocca se stesso nel "giro" precedente, scusami ma sono 10 anni che non pratico l italiano!! forse era meglio in inglese!!!pensavo che se, per esempio dai 20 giri al nastro avresti una risoluzione di 40 steps, 1 per giro + cuando tocchi 1 giro con il seguente, poi il seguente etcforse non e quello che tu stai cercando, e solo un idea.. ;)ciao Quote Link to comment Share on other sites More sharing options...
Screaming_Rabbit Posted September 25, 2007 Report Share Posted September 25, 2007 ...si sono daccordo pero non tutti hanno...... Guys please... >:( this is the international part of the forum... no pizzas here ;D Quote Link to comment Share on other sites More sharing options...
cimo Posted September 25, 2007 Report Share Posted September 25, 2007 absolutely right but:scusami ma sono 10 anni che non pratico l italiano!!translation: sorry but it s 10 years i don t practice italian! .. nice to refresh a little bit my native language... but yeah you are defenetely right.. my idea was about rolling some tape around a piece of plastic, wood, whatever non-conductive material, so that you can achieve more resistance per centimeterMatteo is ok with a long ribbon but i am more keen to smallish thingy to stuff in my travelling bag...Simone Quote Link to comment Share on other sites More sharing options...
Screaming_Rabbit Posted September 25, 2007 Report Share Posted September 25, 2007 i am more keen to smallish thingy to stuff in my travelling bag...... how about the resistance-taper-element of a 10k linear (100mm) fader used in the base and a foil which is well conductive on top (e.g. a copper foil laminated/glued onto a piece of rubber sheet)? I think there is copper foil available with a sticky side, just like scotch tape.Greets, Roger Quote Link to comment Share on other sites More sharing options...
cimo Posted September 25, 2007 Report Share Posted September 25, 2007 ehmm errr uuuuhh ah genius! but also guilty for what i am going to do NOW to my faders.. Quote Link to comment Share on other sites More sharing options...
bosone Posted September 25, 2007 Author Report Share Posted September 25, 2007 yes!i solved the flickering problem!!preamble:i checked now with a tester and between ground and the string wire (signal) at rest (so when the string is not touched) i read 0.21V.i added a diode with threshold voltage of about 0.15V (i had it a home, i was lucky). the diode reads: 1N5180 between ground and signal.in this way flickering was reduce but not deleted.then i had the idea of adding a small cap. it was a cap spared from the sid filter or from the midibox power supply i think, so it should be in the 1-100 nF range, i don't know...anyway, by doing these two operations, the flickering was totally eliminated!! :-)to CIMO: i don't think the tape length is a problem, since ACSensorizer can interpolate any signales between 0 and 5 V.i think it is more a matter of having a good resolution...edit: i feel the diode is completely useless... but now since it's not broken i will not fix it!! :-) Quote Link to comment Share on other sites More sharing options...
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