John M Posted May 1, 2020 Share Posted May 1, 2020 I'm recieving a PX350 in the mail, and as a broke college student who just managed to scrape together the funds to buy a used one on sale, I'm going to try and build a pedal system myself. The PX350 has a 5-pin connector for the SP-33 pedal system. I understand that this is proprietary, so I want to know if there's anything I should be aware of before undertaking this project, so I don't get sued or something? And lastly, do I have to worry about shorting anything out or damaging the piano by testing connectivity between the pins, and if so, is there any precautions I should take? Thank you for your time! Quote Link to comment Share on other sites More sharing options...
Joe Muscara Posted May 2, 2020 Share Posted May 2, 2020 Sued? That would never happen. You could connect it via that connector to your mother and not get sued (connect it to my mom, and I'll sue you, though! ). The warranty might be another matter. But since it's used, that wouldn't be an issue either. As far as shorting it out, I don't know. I don't know if any of the pins carry power or anything significant enough that could cause a problem. I doubt it. 1 Quote Link to comment Share on other sites More sharing options...
John M Posted May 2, 2020 Author Share Posted May 2, 2020 Okay, thank you! I'll probably just appropriate a connector from some junk electronic, since it looks to be fairly easy to match. I'll test all the pins for current, see how much (if any) is flowing through them. At what point would it be high enough that I should be concerned? If there's no voltage or low enough voltage, I'll test connectivity between them and see what I get! Quote Link to comment Share on other sites More sharing options...
CAVA Posted May 2, 2020 Share Posted May 2, 2020 Interesting Project. The PX350 has two connectors for pedals. The standard connector with "mono" 1/4¨ connector at the back and another that uses a propietary connector for the 3 pedal unit located at the bottom of the piano. I suggest you start with a simple damper pedal and then you will use the mono 1/4¨ connector at the back (https://en.wikipedia.org/wiki/Phone_connector_(audio)). That conector uses an off/on signal but it doesn´t mean you can short the two ends and it is on or off, you will probably have some impedance there. I don´t have my CASIO pedal anymore but I have a M Gear (https://amzn.to/3b4jmg9) which has a switch at the bottom so you can use it with a CASIO or a Yamaha, I measured the connector with a tester. In the position ¨normaly open" with the pedal not pressed, if I measure between ground and signal in the connector, it appears as open, if I press the pedal, it measures 100 ohms. This means you can build your own pedal with a 100 ohm resistance and a simple switch. You still need to test what "polarity" to use in the cables but, don´t worry, I don´t think there is a risk of damaging the keyboard if you test in both positions. I suggest to do a google search, there are a lot similar projects with detailed instructions. Of course the project to build a 3 pedal unit (https://amzn.to/3f9ylbI) is more interesting but a lot more complicated project but it offers half damper which would make it interesting. I found this in the forum, there are probably others out there: I hope this helps. Quote Link to comment Share on other sites More sharing options...
John M Posted May 3, 2020 Author Share Posted May 3, 2020 Thank you for your response! Yeah, I have a cheap ebay universal pedal for the back input, I was hoping to come up with something that used the proprietary pedal jack. I wanted to ensure I didn't short anything out or damage the pins, so I was planning on reading the voltage of each pin individually before doing anything, to see if there was enough voltage that I should be worried. I also remember my father telling me to make a connectivity tester with a small incandecent bulb, so if there was a short it would turn the bulb on before shorting anything out. I just bought this piano, i don't want to break it just yet! I plan to build myself a stand for the piano, since I definately don't want to spend the money for a particle-board one when I have the capabilities to make one, so I wanted to try and make a pedal assembly to go with it, for half-damping abilities that won't shift under my foot. Does anyone know the specifics for the potentiometer I would need for the suspend pedal? Thank you all for your help! Quote Link to comment Share on other sites More sharing options...
IanB Posted May 3, 2020 Share Posted May 3, 2020 So I found this Youtube video of somebody who has hacked their pedal board, and according to one of the comments the pinout is this- https://www.youtube.com/watch?v=ZT9gsLpoEjU (5-pin connector inside the keyboard) Pin 1-(red wire) 1/2 sustain Pin 2-full sustain pin 3-sustenuto pin 4-soft pin 5-ground operating as pulldowns, which means you short "pull" the wire to ground to activate the function. I have no way to verify this information. I would try first of all shorting through a 1k resistor to limit current, the pullup resistor in the keyboard I would expect to be in the region of 10k so 1k should be enough to activate it. Quote Link to comment Share on other sites More sharing options...
John M Posted May 3, 2020 Author Share Posted May 3, 2020 Okay, thank you! I greatly appreciate it! I'll be sure to report my results back here! One last question: For the potentiometer for the suspend pedal, how would I wire it for the half-suspend, then full suspend? there's two pins, so I'm assuming at some point it switches over from the half-suspend to the full suspend pin. I could easily bypass this by puting two switches on the pedal, one on the 1/2 position and the other at the full suspend, but that would remove the continuous functionality of the pedal. Quote Link to comment Share on other sites More sharing options...
IanB Posted May 4, 2020 Share Posted May 4, 2020 (edited) Would you not need a pedal that is constructed so there is a switch half way? I can't think of a way to simulate that off the top of my head without using an active (powered) circuit. A potentiometer on its own isn't going to do that however you wire it. I don't think the pedals offer a continuous functionality. Perhaps one of our Casio product experts could confirm the functionality of the official pedals? Edited May 4, 2020 by IanB Quote Link to comment Share on other sites More sharing options...
John M Posted May 4, 2020 Author Share Posted May 4, 2020 I think it's continuous, because I think I remember someone saying that it worked on a continuous scale when used with an MIDI programme, but I might be wrong. I don't think I'd need anything but half-pedal anyways, and I don't think the PX350 supports continous half-pedaling, from what I remember. I'll probably just end up using two switches, since that's the simplest way for me to do it. Does anyone see an issue with both half-sustain and sustain being depressed at the same time? Will I have to make it so the half-sustain disengages when it full sustains? Quote Link to comment Share on other sites More sharing options...
John M Posted May 13, 2020 Author Share Posted May 13, 2020 Okay, so I got it in the mail last tuesday, spent a week banging around on it. They keys are quite clacky, might have to see if I can fix that. Otherwise, a very nice piano and I'm enjoying it immensely. I did try testing the connector, and I couldn't get any of the four functions working besides the sustenuto pedal. I connected pins 1 and 3, and that activates the sustenuto pedal, but I could get no other functions working. Quote Link to comment Share on other sites More sharing options...
Brad Saucier Posted May 13, 2020 Share Posted May 13, 2020 I suspect the pedals simply operate by plain jane potentiometers, nothing special. The only question is which spec pots are used. Quote Link to comment Share on other sites More sharing options...
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