Davidmarks Posted May 22, 2006 Report Share Posted May 22, 2006 Hi,I have a midio 128 with 64 outputs controlling solenoids which are operating pipes on a fairground type organ. Everything OK except one thing. Every now and again a note "sticks" on and i have to shut down and reset. . I have been advised that this is because the system fails to detect a note off signal in the data stream. can anyone help with a possible cure (I can't go off to the beer tent and leave it running in case this happens so it's pretty critical !!) Quote Link to comment Share on other sites More sharing options...
doc Posted May 22, 2006 Report Share Posted May 22, 2006 Sorry for being Off-Topic ....(I can't go off to the beer tent and leave it running in case this happens so it's pretty critical !!)Yes, you can go to the beer tent by having a wireless switch for the reset ... 8) :ogreetsDoc Quote Link to comment Share on other sites More sharing options...
TK. Posted May 22, 2006 Report Share Posted May 22, 2006 Hi David,is this a deterministic failure? Means: are you able to reproduce this with a know sequence of MIDI events? Are you able to record and playback a scenario where Note Off fails (e.g. with a MIDI sequencer)Does it sometimes happen, that a Note On event (a Note) is skipped?So far I remember, the MIDIO128 application has so much "headroom" in the performance, that it is ensured, that an incoming MIDI event can never get lost, regardless of the MIDI traffic load rate.But something which could happen is, that for example the whole apparatus causes spikes on a bad shielded MIDI line - here it helps to improve the shielding.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Davidmarks Posted May 22, 2006 Author Report Share Posted May 22, 2006 Hi Thorsten,So far I have not been able to determine a precise pattern. I played a lot of ragtime piano midi with no problem but as soon asI tried some "fairground music" I got the sticking problem in a random manner. However, I am using a Palm M130 as the midi player and have a home made lead to convert the serial D plug on the Palm to a midi plug. It is quite a long cable and I also have a couple of long leads supplying the board with 35 volts for the Darlington chips so maybe better screening could be the answer. I will do some tidying up , thanks for the suggestion.CheersDavid Quote Link to comment Share on other sites More sharing options...
smashtv Posted May 23, 2006 Report Share Posted May 23, 2006 Hi Thorsten,So far I have not been able to determine a precise pattern. I played a lot of ragtime piano midi with no problem but as soon asI tried some "fairground music" I got the sticking problem in a random manner. However, I am using a Palm M130 as the midi player and have a home made lead to convert the serial D plug on the Palm to a midi plug. It is quite a long cable and I also have a couple of long leads supplying the board with 35 volts for the Darlington chips so maybe better screening could be the answer. I will do some tidying up , thanks for the suggestion.CheersDavidHi DavidI have seen this when I strung up 20 or so feet of random cables and adapters to a palm to kick serial to a laser head on stage....Seems related to the way palm completely floats the ground in their designs (specifically in the cradle). Just enough serial errors to make an occasional glitch, but only when the power was a bit noisy to begin with (You on the same mains circuit with any bad actors?)Whoop almost forgot, what palm software are you using, did you go from cradle to LTC, etc.? There is quite a bit of interest in the Palm/MIDIbox thing.... ;)Take a picture of this music machine thing man! We wanna see it! :)BestSmash Quote Link to comment Share on other sites More sharing options...
Davidmarks Posted May 25, 2006 Author Report Share Posted May 25, 2006 Hi again,Thanks folks, looks as if I was picking up rubbish. I had about a metre of cable from the midio board to the solenoids in the organ and I had mistakenly thought that the internal resistors in the ULN 2308's were sufficient to knock the back emf on the head, evidently not so ! I have now plumbed in loads of IN4001's and the problem (hopefully) seems to have gone away. I will post some info on the main board on Palm and midi and when I have sorted out the technology ( I am pretty ancient) I will send a photograph of the embryo organ Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 25, 2006 Report Share Posted May 25, 2006 Awesome, glad it's sorted and can't wait to see the pics! Quote Link to comment Share on other sites More sharing options...
Billmac Posted March 1, 2007 Report Share Posted March 1, 2007 To DavidmarksWhere did you locate the 1N4001's? On the magnets/solenoids? I depended on the built-in diodes of the 2308's for my piano magnets with no problem. But I don't want a problem (with the pipe magnets of my piano/pipe organ. I'm just starting with that interface.Bill McKeown Quote Link to comment Share on other sites More sharing options...
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