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Hi, Thorsten, You mean something like this:

Thank you very much Thorsten, I have two other questions: 1- MBHP_CORE_LPC17 has 7-pin connection (Vs, Vd, SI, SO, SC, RC1 and RC2) in J8/9 port, and MBHP_DIO_MATRIX has 6-pin connection (Vs, Vd, SI, SO, SC and RC) in J1 Port, is necessary to connect pin P3.26 (RC2) from LPC1769? 2- is possible to protect the CORE at the port J5A0 when connecting the sustain pedal through 74HCT541 IC or an optocoupler like MIDI input ? thanks again. regards Marcelo

Hi Sparx, True, with a bit of effort I could buy a better piano, but I want to do it myself, I would do as a hobby too. As to the question of the optocouplers is that I am thinking to do a "custom" system, with a pcb with only the necessary elements, and then assemble all in one aluminum enclosure as a commercial true piano. I apologize if it is not clear what I write, my English is very poor, and helped me with Gooble translator. With this and the electronics, I do what I can. Thanks for your feedback. regards Marcelo

Sparx thank you very much. I know that this is a hard work, and take a long time, but it is an interesting challenge. Here in Argentina, a quality digital piano is very expensive. For example I use a Casio CDP100 and its keyboard is very noisy. And the sound is not good. And I do not want to spend much money on a better quality piano, I decided to build it myself. If I have a good result, the next step will be to change the Yamaha daughterboard for an embedded system with a good piano VST or soundfonts. All this, plus a good sound system, I'll have a piano of excellent quality, and pleasure of having done it myself. Regards. Marcelo

Thank you very much Thorsten ! This is just what I needed to know, and thanks for the welcome. The sustain connection is clear, but about the optocoupler, you say that I attach, for example, the LPC1769 pin P0.0 (TXD3) to the 74HCT541 IC pin 5 (A3) and pin 15 (Y3) to MIDI daughter board directly ? I will design the circuit with these recommendations. Thank you very much again Thorsten . Regards

Hello, I'm Marcelo from Buenos Aires, Argentina, and I have the crazy idea to building a digital piano. A few weeks ago I found this page that come along and learn, and I think I have everything you need to embark on this adventure. My idea is to built a 88-key digital piano with hammer action keys and velocity sensitive , more or less of the following characteristics: - Keyboard keys made from wood and covered with an acrylic sheet. - Aluminium structure for supporting the keys. - PCBs and moldable silicone buttons for key contacts. - MIDIbox KB aplication with MBHP_CORE_LPC17 and MBHP_DIO_MATRIX modules. - Yamaha DB50XG daughtherboard for sounds. I am designing a keyboard like a Fatar 88 (so you do not think I'm crazy I have to clarify that I am a mechanical designer and I have a small factory of plastic injection molds with CNC machines). This means I have no problem with the mechanical part of the project. But with the electronics I need some help. A few days ago I bought the LPC1769LPCXpressoboard, here in Buenos Aires, and received the Yahama Sound Card from China buying on Ebay. Now I'm designing an electronic circuit based on the MBHP_CORE_LPC17 but only with those peripherals: - USB port. - 3.3 V. Power supply - 2 MIDI in / out. - Matrix DIO connection (through the 74HCT541 IC) - Standard sustain pedal connection through J5A port. Here are the first questions: - Is it necessary to use the optocoupler and the IC 74HCT00 to connect the LPC1769LPCXpressoboard midiout to the Yamaha Card midi in ? (attach the diagram). - how I can to connect a standard sustain pedal (Nomal Open switch ) to port J5A For CC#64 midi messages (velocity 0 = off , velocity 127 = on) ? I hope you find this project interesting and can help me to do it. The next days I will be discussing and documenting progress in this forum. Thank you very much Regards. Marcelo