Guest dragon.69 Posted June 9, 2003 Report Share Posted June 9, 2003 Newbie warning!hello all. I have a concept question and would love to have some feed back, I have a vision of a midi controller that would essentially be a motor or an encoder that as it spins will increase or decrease the pitch of a note (likely a continous loop of a saw or square) possibly it will have a second motor with speed control to maintain a pitch that will turn the encoder, a small wheel will be attached to the encoder like a turntable that will allow hand manipulation of the wheel. thats the long and short of the concept. now can pitch be controlled this way and if so how? Quote Link to comment Share on other sites More sharing options...
stryd_one Posted June 9, 2003 Report Share Posted June 9, 2003 why not use a combination of lfo's and pitchbend and modwheels modulating pitch?... Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 9, 2003 Report Share Posted June 9, 2003 Well mostly that would work to get the sound that i love but essentially I'd really like to get the motor to work. I think having a spinning disc to interact with would just be a little different. Although having several spinning discs controlling different parameters would be cool too. There has to be someone who can point me to the right circuit to do this. Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 9, 2003 Report Share Posted June 9, 2003 Oh yeah one of the difficulties with mod wheels is there are start and stop points on the wheels. this would have none of that. more of a constant state of pitch until touched. Quote Link to comment Share on other sites More sharing options...
supraanimo Posted June 10, 2003 Report Share Posted June 10, 2003 Interresting concept, although it could be hard to realize. The rotary encoder you would have would wear much faster than normal wear also getting the system to recognize the fader's constant rotation would be kind of an interresting task. But i say go for it....Nothing is impossible for a DIYer. Quote Link to comment Share on other sites More sharing options...
Guest eBetan Posted June 14, 2003 Report Share Posted June 14, 2003 Here is an idea, there is a measuring  device I once saw in a physics class that had a little spinning pulley with spokes or holes. There was a light sensor on one side of the wheel and a infrared (I think) small light source on the other. the sensor would just transmit the ticks of light and light inturruption. This was then interpreted to be a velocity. I think there are cheaper devices employing similar technologies (mice...the kind with a metal and rubber ball under them, and stuff like that?)either way, I am sure these sensors are sending back velocity and speed information, its just a matter of taking that information and putting it into a usable format (beyond my technical know-how!)...and the last part (I would think) would have to be done in software...which is the "zero-ing" of that sensor at whatever constant speed the motor would be.  I like your idea!....would really keep the feel of a turntable!....only issue is that you would have to make sure to set your values so any little jitters or the natural irregularities of a physical motor would be ignored (unless its actually part of what you might want!) Quote Link to comment Share on other sites More sharing options...
stryd_one Posted June 14, 2003 Report Share Posted June 14, 2003 I see the idea now...Yeh you could do this in the same way anti-skid braking works (at least on airplanes I don't know squat about cars heheh)... You basically watch the speed of rotation, and measure the change, and react according to change (IE if the wheel is turning slower than the plane's speed should make it, its skidding so let the brake off, etc)...would be pretty easy with a turntable because you can use a fixed speed of rotation so you dont even have to monitor the speed...then you just measure the difference between the fixed rotation speed (shall we say 45rpm? heh) and the actual RPM read from the light sensor ... The math needed to do this in MIOS is already there, take a look at the MIOS code for some of the projects, or on the PICList website... Definitely not hard to time a series of pulses and measure a BPM, nor to measure the difference between the two and send a pitchbend message accordingly...But the thing is, there's infinite room for change in speed going faster, and a limited, but still fairly broad range going slower... I mean how could we get it to handle it if you stop the spinning disc, or do a back spin, or a forward spin for that matter? Most MIDI synths and samplers only pitchbend a few octaves either way at best....doh!Food for thought... I'm willing to help with code if ya like but I'm not sure it's really workable... I mean you could make the device, there's 16,383 different pitchbend settings after all (14 bits...), so lots of different speeds could be accounted for, but the thing is that not much will be able to make really practical use of it :( I dunno, maybe I missed the point again heheh Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 15, 2003 Report Share Posted June 15, 2003 awesome advice! i knew someone out there would have what this project needed. as for counting pulses thats exactly what I figured, you set up the code and 0 pulses = no sound, 1-3 per second = C0 3-6per second =C0# so on and so on. You chop up the keyboard into speed segments that represent a full size keyboard, you would have to have some glide in the synth to make the transition from key to key smooooth. I love this idea and its been haunting me for a while now. I am not a coder, I am an idea man myself I think of weird things like this, so any volunteers to help with coding are definitley welcome. The answer to the project is pulse counting and someone knows how to do it. Anyone else? Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 15, 2003 Report Share Posted June 15, 2003 Wait I may be on to something! how about using a small generator like they use to light bicyle headlamps? the faster they turn the more voltage the generate. would this be enough to create the differing CV's to make my dream a reality? Quote Link to comment Share on other sites More sharing options...
Guest Xcen Posted June 15, 2003 Report Share Posted June 15, 2003 I'm far from anything like an expert but I'm not sure wether you could produce enough energy by just turning the wheel? some1 would have to correct me on this...Although I would use it for other uses that pitch, this project could be very interesting if we could get it to work (endless "horizontal" modwheel... ?) It would be interesting as a scratch device thing... anywayz, don't gi ve up! Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 16, 2003 Report Share Posted June 16, 2003 I think doing something with gears or pullies would help to get it to the proper speed. But yeah My original vision was because to me the best scratches come for steady tones saw waves high sines and so forth then the idea just came to me, the wheel! thanks for your advice anyone else? Quote Link to comment Share on other sites More sharing options...
Guest Flownezz Posted June 16, 2003 Report Share Posted June 16, 2003 Hi Dragon, another aproach you could take would be to emulate a record's interaction with a slip mat, so have some kind of friction device between the encoder and the motor. This would be a lot simpler than using gears and feel more like the real thing...Edit: Just another idea, if you could rip the direct drive mechanism out of an old Turntable, you could use the original pitch controll too ;D... Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 17, 2003 Report Share Posted June 17, 2003 I like it, can anyone point me to a good explanation of how CV's work as far as triggers go? Quote Link to comment Share on other sites More sharing options...
Guest Shaggy2Dope Posted June 19, 2003 Report Share Posted June 19, 2003 I'm no expert on engineering, mechanics, or electronics, but the physics thing that eBetan was talking about, with the light sensor could work nicely ... motor spins the disk/platter at a certain rpm, which would be 0, certain note, or equivelent to the centre of a crossfade, and when you speed it up by hand or by speed control, it will increase the note/crossfade ... that is ... if I am reading what he said correctly ...That would be awesome for dj mixing ... All you would have to do is get the light cycles/impulses/whatever they are recognised ? Quote Link to comment Share on other sites More sharing options...
Guest dragon.69 Posted June 19, 2003 Report Share Posted June 19, 2003 I like it! Quote Link to comment Share on other sites More sharing options...
Guest Flownezz Posted June 20, 2003 Report Share Posted June 20, 2003 Hi again dragon, you might find this thread interesting... http://www.midibox.org/cgi-bin/yabb/YaBB.cgi?board=concepts;action=display;num=1047939069 Quote Link to comment Share on other sites More sharing options...
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