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Hello- I am working on some BX controlled MIDI sensors for an interactive art piece. Each BX will be handling around 12 inputs...a mixture of switches, and variable resistors. The sensors will be around 50 feet from the computer that will be receiving the MIDI signals. This is right around the max distance for MIDI communication, and I wanted to get the groups thoughts on the best way to approach this. It looks like I have a couple of options: 1) have all the BX modules very close to the computer (no midi issues), and run a long cable to the sensors. Are there any issues with having a 50ft cable connecting the sensors and the BX? All the sensors will either be switches, variable resistors, or devices that output a logic low on activation. I have not tried anything at this length, but it does seem like the easiest solution. I have seen some 15 wire cable that may work for this... 2) have the BX modules very close to the sensors, and figure out some way to amplify the MIDI signals coming from them. I am aware of the MAX232 chip, but do not know if it can handle the odd baud rate. Has anyone dealt with MIDI over long distances? Thanks for any suggestions- -Howie

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Howie, You're going to have problems as long as your sensor is so far from your A2D. Noise and line variation will kill you. When dealing with analog you must have the sensor pre-condition the signal for long distance transmission. Either boost and smooth the signal at the sensor with an op-amp so you have solid, high drive signal, or put the A2D at the sensor site and transmit the data back via some kind of serial connection. Another comment; I've never used an A2D that was totally rock solid - you may have to condition and average changes with software... DLC -- --------------------------------------- Dennis Clark http://www.techtoystoday.com --------------------------------------- <tt> Guess I will respond to myself ;)<BR> <BR> I have tested having the variable resistor (bend sensor) at the end <BR> of a 50ft cable, and I am getting some pretty unstable results at the <BR> ADC...does anyone have any thoughts on a hardware solution to smooth <BR> out the voltage? It is jumping around too much, causing quick <BR> switching between the MIDI notes being played. I can probably do <BR> something in SW, but I wanted to avoid it if I can...<BR> <BR> <BR> Another idea I had was to keep the sensor cables short, and have the <BR> long cables carry serial info. The idea is that I would have 4 or <BR> 5 "remote" BX units sending serial messages (at a standard baud rate) <BR> to a central BX that would take turns reading each of the remote <BR> units, combine those messages into an output queue and then send one <BR> MIDI out signal. Would it be possible to check 4 or 5 serial inputs <BR> by switching com3 around, while sending a steady serial out on com1 <BR> with the UBRR register tweaked to allow the MIDI baud rate? <BR> <BR> Again, *any* thoughts would be appreciated...<BR> -Howie<BR> <BR> <BR> <BR> <BR> --- In basicx@y..., "howieoakes" <howie@c...> wrote:<BR> > Hello-<BR> > <BR> > I am working on some BX controlled MIDI sensors for an interactive <BR> > art piece. Each BX will be handling around 12 inputs...a mixture of <BR> > switches, and variable resistors. <BR> > <BR> > The sensors will be around 50 feet from the computer that will be <BR> > receiving the MIDI signals. This is right around the max distance <BR> for <BR> > MIDI communication, and I wanted to get the groups thoughts on the <BR> > best way to approach this. It looks like I have a couple of options:<BR> > <BR> > 1) have all the BX modules very close to the computer (no midi <BR> > issues), and run a long cable to the sensors. Are there any issues <BR> > with having a 50ft cable connecting the sensors and the BX? All the <BR> > sensors will either be switches, variable resistors, or devices <BR> that <BR> > output a logic low on activation. I have not tried anything at this <BR> > length, but it does seem like the easiest solution. I have seen <BR> some <BR> > 15 wire cable that may work for this...<BR> > <BR> > 2) have the BX modules very close to the sensors, and figure out <BR> some <BR> > way to amplify the MIDI signals coming from them. I am aware of the <BR> > MAX232 chip, but do not know if it can handle the odd baud rate. <BR> Has <BR> > anyone dealt with MIDI over long distances?<BR> > <BR> > <BR> > Thanks for any suggestions-<BR> > <BR> > -Howie<BR> <BR> </tt <br> <tt>">Yahoo! Terms of Service</a>.</tt> </br

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Guess I will respond to myself ;) I have tested having the variable resistor (bend sensor) at the end of a 50ft cable, and I am getting some pretty unstable results at the ADC...does anyone have any thoughts on a hardware solution to smooth out the voltage? It is jumping around too much, causing quick switching between the MIDI notes being played. I can probably do something in SW, but I wanted to avoid it if I can... Another idea I had was to keep the sensor cables short, and have the long cables carry serial info. The idea is that I would have 4 or 5 "remote" BX units sending serial messages (at a standard baud rate) to a central BX that would take turns reading each of the remote units, combine those messages into an output queue and then send one MIDI out signal. Would it be possible to check 4 or 5 serial inputs by switching com3 around, while sending a steady serial out on com1 with the UBRR register tweaked to allow the MIDI baud rate? Again, *any* thoughts would be appreciated... -Howie --- In basicx@y..., "howieoakes" <howie@c...> wrote: > Hello- > > I am working on some BX controlled MIDI sensors for an interactive > art piece. Each BX will be handling around 12 inputs...a mixture of > switches, and variable resistors. > > The sensors will be around 50 feet from the computer that will be > receiving the MIDI signals. This is right around the max distance for > MIDI communication, and I wanted to get the groups thoughts on the > best way to approach this. It looks like I have a couple of options: > > 1) have all the BX modules very close to the computer (no midi > issues), and run a long cable to the sensors. Are there any issues > with having a 50ft cable connecting the sensors and the BX? All the > sensors will either be switches, variable resistors, or devices that > output a logic low on activation. I have not tried anything at this > length, but it does seem like the easiest solution. I have seen some > 15 wire cable that may work for this... > > 2) have the BX modules very close to the sensors, and figure out some > way to amplify the MIDI signals coming from them. I am aware of the > MAX232 chip, but do not know if it can handle the odd baud rate. Has > anyone dealt with MIDI over long distances? > Thanks for any suggestions- > > -Howie

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use rs232 convert the rs232 to rs485 or rs422. this is a single chip change and will enable longer distances. MIDI is not the best choise as there is no booster for it. --- howieoakes <> wrote: > Guess I will respond to myself ;) > > I have tested having the variable resistor (bend sensor) at the end > of a 50ft cable, and I am getting some pretty unstable results at the > ADC...does anyone have any thoughts on a hardware solution to smooth > out the voltage? It is jumping around too much, causing quick > switching between the MIDI notes being played. I can probably do > something in SW, but I wanted to avoid it if I can... > Another idea I had was to keep the sensor cables short, and have the > long cables carry serial info. The idea is that I would have 4 or > 5 "remote" BX units sending serial messages (at a standard baud rate) > to a central BX that would take turns reading each of the remote > units, combine those messages into an output queue and then send one > MIDI out signal. Would it be possible to check 4 or 5 serial inputs > by switching com3 around, while sending a steady serial out on com1 > with the UBRR register tweaked to allow the MIDI baud rate? > > Again, *any* thoughts would be appreciated... > -Howie > > > --- In basicx@y..., "howieoakes" <howie@c...> wrote: > > Hello- > > > > I am working on some BX controlled MIDI sensors for an interactive > > art piece. Each BX will be handling around 12 inputs...a mixture of > > switches, and variable resistors. > > > > The sensors will be around 50 feet from the computer that will be > > receiving the MIDI signals. This is right around the max distance > for > > MIDI communication, and I wanted to get the groups thoughts on the > > best way to approach this. It looks like I have a couple of options: > > > > 1) have all the BX modules very close to the computer (no midi > > issues), and run a long cable to the sensors. Are there any issues > > with having a 50ft cable connecting the sensors and the BX? All the > > sensors will either be switches, variable resistors, or devices > that > > output a logic low on activation. I have not tried anything at this > > length, but it does seem like the easiest solution. I have seen > some > > 15 wire cable that may work for this... > > > > 2) have the BX modules very close to the sensors, and figure out > some > > way to amplify the MIDI signals coming from them. I am aware of the > > MAX232 chip, but do not know if it can handle the odd baud rate. > Has > > anyone dealt with MIDI over long distances? > > > > > > Thanks for any suggestions- > > > > -Howie > __________________________________________________

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The problem is that the end result *does* need to be MIDI to interface with the computer that is controlling all the sounds... I am thinking about using he Max232 chips to send the muliple (standard) serial connections to a "master" BX...then have this master combine all the seperate streams into one MIDI out stream...I need to get more BX chips to try this out. Does anyone know why this would not work? -4 BX remote units all connected to a central BX (max232 chips to allow long distance cable run) -the master constantly switches com3 in a loop to read the serial outputs of the remotes (they are sending 3 byte messages) I may have to implement some flow control here... -The master combines these messages into a common queue that sends one serial stream out of COM1 using the MIDI baud rate... The only problem is that I could see messages getting "backed up" at the controllers depending on how much activity there is... Lots of testing to do- --- In basicx@y..., Tony Brenke <trbrenke@y...> wrote: > use rs232 > convert the rs232 to rs485 or rs422. > > this is a single chip change and will enable longer distances. > MIDI is not the best choise as there is no booster for it. > --- howieoakes <howie@c...> wrote: > > Guess I will respond to myself ;) > > > > I have tested having the variable resistor (bend sensor) at the end > > of a 50ft cable, and I am getting some pretty unstable results at the > > ADC...does anyone have any thoughts on a hardware solution to smooth > > out the voltage? It is jumping around too much, causing quick > > switching between the MIDI notes being played. I can probably do > > something in SW, but I wanted to avoid it if I can... > > > > > > Another idea I had was to keep the sensor cables short, and have the > > long cables carry serial info. The idea is that I would have 4 or > > 5 "remote" BX units sending serial messages (at a standard baud rate) > > to a central BX that would take turns reading each of the remote > > units, combine those messages into an output queue and then send one > > MIDI out signal. Would it be possible to check 4 or 5 serial inputs > > by switching com3 around, while sending a steady serial out on com1 > > with the UBRR register tweaked to allow the MIDI baud rate? > > > > Again, *any* thoughts would be appreciated... > > -Howie > > > > > > > > > > --- In basicx@y..., "howieoakes" <howie@c...> wrote: > > > Hello- > > > > > > I am working on some BX controlled MIDI sensors for an interactive > > > art piece. Each BX will be handling around 12 inputs...a mixture of > > > switches, and variable resistors. > > > > > > The sensors will be around 50 feet from the computer that will be > > > receiving the MIDI signals. This is right around the max distance > > for > > > MIDI communication, and I wanted to get the groups thoughts on the > > > best way to approach this. It looks like I have a couple of options: > > > > > > 1) have all the BX modules very close to the computer (no midi > > > issues), and run a long cable to the sensors. Are there any issues > > > with having a 50ft cable connecting the sensors and the BX? All the > > > sensors will either be switches, variable resistors, or devices > > that > > > output a logic low on activation. I have not tried anything at this > > > length, but it does seem like the easiest solution. I have seen > > some > > > 15 wire cable that may work for this... > > > > > > 2) have the BX modules very close to the sensors, and figure out > > some > > > way to amplify the MIDI signals coming from them. I am aware of the > > > MAX232 chip, but do not know if it can handle the odd baud rate. > > Has > > > anyone dealt with MIDI over long distances? > > > > > > > > > Thanks for any suggestions- > > > > > > -Howie > > > > > > > > > > > > > > > > __________________________________________________

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this would work, BUT RS232 will not do it. if you can use BX-01's this will be flawless over 5000 feet. RS485 is built in. --- howieoakes <> wrote: > The problem is that the end result *does* need to be MIDI to > interface with the computer that is controlling all the sounds... > > I am thinking about using he Max232 chips to send the muliple > (standard) serial connections to a "master" BX...then have this > master combine all the seperate streams into one MIDI out stream...I > need to get more BX chips to try this out. Does anyone know why this > would not work? > > -4 BX remote units all connected to a central BX (max232 chips to > allow long distance cable run) > > -the master constantly switches com3 in a loop to read the serial > outputs of the remotes (they are sending 3 byte messages) I may have > to implement some flow control here... > > -The master combines these messages into a common queue that sends > one serial stream out of COM1 using the MIDI baud rate... > > The only problem is that I could see messages getting "backed up" at > the controllers depending on how much activity there is... > > Lots of testing to do- > > --- In basicx@y..., Tony Brenke <trbrenke@y...> wrote: > > use rs232 > > convert the rs232 to rs485 or rs422. > > > > this is a single chip change and will enable longer distances. > > MIDI is not the best choise as there is no booster for it. > > > > > > --- howieoakes <howie@c...> wrote: > > > Guess I will respond to myself ;) > > > > > > I have tested having the variable resistor (bend sensor) at the > end > > > of a 50ft cable, and I am getting some pretty unstable results at > the > > > ADC...does anyone have any thoughts on a hardware solution to > smooth > > > out the voltage? It is jumping around too much, causing quick > > > switching between the MIDI notes being played. I can probably do > > > something in SW, but I wanted to avoid it if I can... > > > > > > > > > Another idea I had was to keep the sensor cables short, and have > the > > > long cables carry serial info. The idea is that I would have 4 or > > > 5 "remote" BX units sending serial messages (at a standard baud > rate) > > > to a central BX that would take turns reading each of the remote > > > units, combine those messages into an output queue and then send > one > > > MIDI out signal. Would it be possible to check 4 or 5 serial > inputs > > > by switching com3 around, while sending a steady serial out on > com1 > > > with the UBRR register tweaked to allow the MIDI baud rate? > > > > > > Again, *any* thoughts would be appreciated... > > > -Howie > > > > > > > > > > > > > > > --- In basicx@y..., "howieoakes" <howie@c...> wrote: > > > > Hello- > > > > > > > > I am working on some BX controlled MIDI sensors for an > interactive > > > > art piece. Each BX will be handling around 12 inputs...a > mixture of > > > > switches, and variable resistors. > > > > > > > > The sensors will be around 50 feet from the computer that will > be > > > > receiving the MIDI signals. This is right around the max > distance > > > for > > > > MIDI communication, and I wanted to get the groups thoughts on > the > > > > best way to approach this. It looks like I have a couple of > options: > > > > > > > > 1) have all the BX modules very close to the computer (no midi > > > > issues), and run a long cable to the sensors. Are there any > issues > > > > with having a 50ft cable connecting the sensors and the BX? All > the > > > > sensors will either be switches, variable resistors, or devices > > > that > > > > output a logic low on activation. I have not tried anything at > this > > > > length, but it does seem like the easiest solution. I have seen > > > some > > > > 15 wire cable that may work for this... > > > > > > > > 2) have the BX modules very close to the sensors, and figure > out > > > some > > > > way to amplify the MIDI signals coming from them. I am aware of > the > > > > MAX232 chip, but do not know if it can handle the odd baud > rate. > > > Has > > > > anyone dealt with MIDI over long distances? > > > > > > > > > > > > Thanks for any suggestions- > > > > > > > > -Howie > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > __________________________________________________ > > > > __________________________________________________

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To improve the noise problems on the sensors, use twisted shielded cable to connect to the processor. Tie both the shield and the return line to ground near the processor. Leave the shield line floating at the sensor end. For a resistive sensor, you can switch to a current mode by putting a resistor between the ADC input and ground. The voltage across that resistor will then change as the sensor resistance changes. Noise usually has little energy content and dampens out quick when fed into a load. You are giving up dynamic range, however. There are techniques to shed the noise that the long leads induce but most require active components. --- In basicx@y..., "howieoakes" <howie@c...> wrote: > The problem is that the end result *does* need to be MIDI to > interface with the computer that is controlling all the sounds... > > I am thinking about using he Max232 chips to send the muliple > (standard) serial connections to a "master" BX...then have this > master combine all the seperate streams into one MIDI out stream...I > need to get more BX chips to try this out. Does anyone know why this > would not work? > > -4 BX remote units all connected to a central BX (max232 chips to > allow long distance cable run) > > -the master constantly switches com3 in a loop to read the serial > outputs of the remotes (they are sending 3 byte messages) I may have > to implement some flow control here... > > -The master combines these messages into a common queue that sends > one serial stream out of COM1 using the MIDI baud rate... > > The only problem is that I could see messages getting "backed up" at > the controllers depending on how much activity there is... > > Lots of testing to do- > > --- In basicx@y..., Tony Brenke <trbrenke@y...> wrote: > > use rs232 > > convert the rs232 to rs485 or rs422. > > > > this is a single chip change and will enable longer distances. > > MIDI is not the best choise as there is no booster for it. > > > > > > --- howieoakes <howie@c...> wrote: > > > Guess I will respond to myself ;) > > > > > > I have tested having the variable resistor (bend sensor) at the > end > > > of a 50ft cable, and I am getting some pretty unstable results at > the > > > ADC...does anyone have any thoughts on a hardware solution to > smooth > > > out the voltage? It is jumping around too much, causing quick > > > switching between the MIDI notes being played. I can probably do > > > something in SW, but I wanted to avoid it if I can... > > > > > > > > > Another idea I had was to keep the sensor cables short, and have > the > > > long cables carry serial info. The idea is that I would have 4 or > > > 5 "remote" BX units sending serial messages (at a standard baud > rate) > > > to a central BX that would take turns reading each of the remote > > > units, combine those messages into an output queue and then send > one > > > MIDI out signal. Would it be possible to check 4 or 5 serial > inputs > > > by switching com3 around, while sending a steady serial out on > com1 > > > with the UBRR register tweaked to allow the MIDI baud rate? > > > > > > Again, *any* thoughts would be appreciated... > > > -Howie > > > > > > > > > > > > > > > --- In basicx@y..., "howieoakes" <howie@c...> wrote: > > > > Hello- > > > > > > > > I am working on some BX controlled MIDI sensors for an > interactive > > > > art piece. Each BX will be handling around 12 inputs...a > mixture of > > > > switches, and variable resistors. > > > > > > > > The sensors will be around 50 feet from the computer that will > be > > > > receiving the MIDI signals. This is right around the max > distance > > > for > > > > MIDI communication, and I wanted to get the groups thoughts on > the > > > > best way to approach this. It looks like I have a couple of > options: > > > > > > > > 1) have all the BX modules very close to the computer (no midi > > > > issues), and run a long cable to the sensors. Are there any > issues > > > > with having a 50ft cable connecting the sensors and the BX? All > the > > > > sensors will either be switches, variable resistors, or devices > > > that > > > > output a logic low on activation. I have not tried anything at > this > > > > length, but it does seem like the easiest solution. I have seen > > > some > > > > 15 wire cable that may work for this... > > > > > > > > 2) have the BX modules very close to the sensors, and figure > out > > > some > > > > way to amplify the MIDI signals coming from them. I am aware of > the > > > > MAX232 chip, but do not know if it can handle the odd baud > rate. > > > Has > > > > anyone dealt with MIDI over long distances? > > > > > > > > > > > > Thanks for any suggestions- > > > > > > > > -Howie > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > __________________________________________________ > >

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