I was thinking about making my own MIDI Hammond organ clone. I will be using this to do it: MGB - MIDI Gadgets Boutique
The schematic says that for the keys on both the upper and lower manual, the pins on the board connect to the key contact. Then it works as a switch, closing the circuit when a key is depressed. This much makes perfect sense to me.
I'll just take the keys and contact strip out of a cheapo keyboard/MIDI controller I find. But how do I connect it to the key contact? I was wondering if anyone knows where the wire should solder to on these carbon contact keybeds that they all come with now?
Any help very much appreciated!
The schematic says that for the keys on both the upper and lower manual, the pins on the board connect to the key contact. Then it works as a switch, closing the circuit when a key is depressed. This much makes perfect sense to me.
I'll just take the keys and contact strip out of a cheapo keyboard/MIDI controller I find. But how do I connect it to the key contact? I was wondering if anyone knows where the wire should solder to on these carbon contact keybeds that they all come with now?
Any help very much appreciated!
This is one of the boards in the bundle which connects the keys to the system. This one is for the upper manual, but all boards are exactly the same principle. As you can see, Pin 1 connects to key 1, which acts as a switch when it is pressed down and closes the circuit. When soldered to the key contact, this is exactly what will happen. But I'm stumped on how I'd solder it to one of these carbon key contacts which all the modern keyboards have.
By the description in the above schematic, I presume this is what you are planning to use, there is a loom feeding the 16pin sockets. You will probably have to utilise the original loom as soldering to carbon is not feasible. Yamaha and other major manufacturers use a carbon pad to contact across two copper pads on a circuit board. Using two per key about an inch apart means that as one contacts before the other, the first contact makes the note and the second increases the volume the shorter the time delay between each contact pad. Mimicking the speed or hardness of the note being played.
It is virtually impossible to solder to the silver traces on the membrane switches, you would be better trying to find a socket that the flimsy plastic can plug into.
I've done some digging! Firstly, I'll apologise for confusing things, the link I posted at first is wrong! I should be using a different bundle. That bundle is for keys which have a common wire running through every key (a busbar as it's called in Hammond organs). So if I had a bunch of Hammond organ keys, that would be great and simple. That would be the easiest option, but I can't afford that.
The bundle to use is this one: MGB - MIDI Gadgets Boutique
It comes with the "4x sm8x8" boards. This is for ripping the keyboards out of standard keyboards and synthesizers. In keyboards there is a scanmatrix board. This board, on a 61 note keyboard, is arranged to have 8 colums and 8 rows. Without getting too in depth, it's almost like a way of multi-tasking; it checks each column simultaneously to see if one or more of the keys are activated on one of the rows in that column. The only reason these are used is because if they only need 16 wires to wire 61 keys versus 62 wires, which would be incredibly thick and awkward!
More can be read at Code Tinker Hack: How to turn Piano toy into MIDI keyboard (using Arduino/Atmega) and Keyboard matrix circuit - Wikipedia, the free encyclopedia if you want to know more.
So I get how you solder onto these now and how they work (I think - if I run into any problems, I'll post again!) Only one last question.
Still not quite plug and play yet unfortunately! I need to now decode the scanmatrix back into it's individual key signals (which is what, once connected correctly, the board I'll buy will do).
On here (MGB - MIDI Gadgets Boutique) it says I need diodes (1N4149 or similar) between the wire and each solder joint to the scanmatric board. It says if I don't, it will pick up the wrong messages. I read without these diodes, it will be monophonic and not polyphonic, so if I pressed two keys or more then the messages would map one key in the complete wrong place rather than the multiple keys at the same time. On the schematic of the board I'll be using:
there's no diodes! Is this just a simple omission to make the wiring diagram more simple, or do I not need diodes with this? I think I'll get the diodes as it seems like I should need them, but has anyone here got any ideas?
The bundle to use is this one: MGB - MIDI Gadgets Boutique
It comes with the "4x sm8x8" boards. This is for ripping the keyboards out of standard keyboards and synthesizers. In keyboards there is a scanmatrix board. This board, on a 61 note keyboard, is arranged to have 8 colums and 8 rows. Without getting too in depth, it's almost like a way of multi-tasking; it checks each column simultaneously to see if one or more of the keys are activated on one of the rows in that column. The only reason these are used is because if they only need 16 wires to wire 61 keys versus 62 wires, which would be incredibly thick and awkward!
More can be read at Code Tinker Hack: How to turn Piano toy into MIDI keyboard (using Arduino/Atmega) and Keyboard matrix circuit - Wikipedia, the free encyclopedia if you want to know more.
So I get how you solder onto these now and how they work (I think - if I run into any problems, I'll post again!) Only one last question.
Still not quite plug and play yet unfortunately! I need to now decode the scanmatrix back into it's individual key signals (which is what, once connected correctly, the board I'll buy will do).
On here (MGB - MIDI Gadgets Boutique) it says I need diodes (1N4149 or similar) between the wire and each solder joint to the scanmatric board. It says if I don't, it will pick up the wrong messages. I read without these diodes, it will be monophonic and not polyphonic, so if I pressed two keys or more then the messages would map one key in the complete wrong place rather than the multiple keys at the same time. On the schematic of the board I'll be using:
there's no diodes! Is this just a simple omission to make the wiring diagram more simple, or do I not need diodes with this? I think I'll get the diodes as it seems like I should need them, but has anyone here got any ideas?
Well that's the thing, I don't actually have the keyboard yet, but I just want to plan this out in advance before I spend a ton of money on this.
Most keyboards use the same system though. I'll just use a cheap Casio keyboard for the guts. The keys won't be a great feel, but I can always upgrade the keys at another time.
Basically, there's a scanmatrix system in the keyboard. The keys connect to this by a ribbon cable. It basically just means that less wires are needed to connect the keys to the circuit board. I need to kind of decode that. Basically, the board I'm buying expands it so that MIDI messages can be read from them (it'd take far too long to read them off a scanmatrix, you'd get a delay of about 5 secs between pressing a key and a sound coming out!) In keyboards, the scanmatrix is an 8x8 system; my circuit board makes this into a 2x64 system.
Here's a Casio keyboard circuit board. You can see the ribbon cable coming from the keys. This photo shows the underside of the ribbon cable connector plug. Under it are the soldered teminals for the ribbon cable plug. The rows are highlighted in yellow on the right, the columns in red on the left:
Now I basically have to make one connection from each row to my circuit board and 8 connections from each column to my circuit board. How would you recommend I best do this? I see it as there being two options: either I keep the PCB for the entire keyboard and make solder connections to the underside of the ribbon connector plug at the solder terminals; or I use a breadboard which I'll plug the ribbon cable into and then make the connections from the breadboard. Which do you think would be easier? And would both of them work?
I really have quite little electronics knowledge, just trying to get my head stuck in there and learn along the way, while most importantly having fun!
Most keyboards use the same system though. I'll just use a cheap Casio keyboard for the guts. The keys won't be a great feel, but I can always upgrade the keys at another time.
Basically, there's a scanmatrix system in the keyboard. The keys connect to this by a ribbon cable. It basically just means that less wires are needed to connect the keys to the circuit board. I need to kind of decode that. Basically, the board I'm buying expands it so that MIDI messages can be read from them (it'd take far too long to read them off a scanmatrix, you'd get a delay of about 5 secs between pressing a key and a sound coming out!) In keyboards, the scanmatrix is an 8x8 system; my circuit board makes this into a 2x64 system.
Here's a Casio keyboard circuit board. You can see the ribbon cable coming from the keys. This photo shows the underside of the ribbon cable connector plug. Under it are the soldered teminals for the ribbon cable plug. The rows are highlighted in yellow on the right, the columns in red on the left:
Now I basically have to make one connection from each row to my circuit board and 8 connections from each column to my circuit board. How would you recommend I best do this? I see it as there being two options: either I keep the PCB for the entire keyboard and make solder connections to the underside of the ribbon connector plug at the solder terminals; or I use a breadboard which I'll plug the ribbon cable into and then make the connections from the breadboard. Which do you think would be easier? And would both of them work?
I really have quite little electronics knowledge, just trying to get my head stuck in there and learn along the way, while most importantly having fun!
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I've tried to plan this out on a breadboard, but the more I try, the more confused I get!
Do you think just soldering wires from underneath the ribbon cable connector would work? That would probably be the simplest way, so long as it works.
Do you think just soldering wires from underneath the ribbon cable connector would work? That would probably be the simplest way, so long as it works.
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