gres
Full Member level 4
It’s a hobbyist construction, 25 key midi keyboards for electric bodies. I made it for my younger brother who likes playing at keyboards. Prices of new devices are too big.
Based element is a solid box with keys ( all of these I made with plywood. Elastic suspensions couse that you don’t have to use any sprongs, and has no clearances. To avoid tendency of moving and rotation of keys, guides I made of aluminum pipes.
As a electric we have 25 microswithers and very simple driver.
Driver is so simple that there is no diagram for it.
Heart of the system is ATMEGA88 microcontroller, with MIDI transmitter and receiver. Keyboard is scanned in matrix mode (4x8) with diode at each channel ( no problem with pressing of all keys at once). As I don’t like to design boards, I’ve used universal board. To be hones, mechanism of pressing the micros switches is sucks, althought is so simple. Angle bar made of PCV are not good as they like bo brake down.
Device is set in C language for AVR studio. Source code is almost as simple as physical aspect of electronics.
To create all device you need about 3 weekends – day for soldering, 3 for mechanics, 2 for software .
Once againt I’m so sory that there is no documentation.
Original text you can find at https://www.elektroda.pl/rtvforum/topic1573560.html
Legs keyboard for keyboard