Cheap input fun

Discussion in 'NDS - Emulation and Homebrew' started by Blue Pen, Feb 7, 2011.

  1. Blue Pen

    Blue Pen Newbie

    Feb 7, 2011
    United States
    Hi. It's my first post, so apologies if I screwed it up.

    Has anyone had any luck coding for the DS Easy Piano Controller?

    It is a 13 button piano keyboard toy that plugs into the DS much like the Guitar Hero Guitar Grip. It uses the GBA slot (so won't work with the DSi). They are cheap in the UK now. Kinda fun.

    I quite like the idea of dismantling it and using the design for more general DS input. With its 13 keys this device should be better than the (4 button => only 4bit input) Guitar Grip Controller as an input base. But it is worth noting that it is actually quite good intact as a piano game controller too. The piano/music homebrew that rely on the touch screen are a bit pointless since they can't handle chords (multiple simultaneous presses). It is clear from the supplied game that all of the keys on this device can be read independently (13button/bit input).

    To get it going, I first played with the guitar grip controller code from but I have (so far) been unable to adapt this code to deal with the piano controller properly.

    I have attached photos of the Piano Controller circuit boards. The 2 piano boards are on the right (with the ribbon cable). I have included the Guitar Grip Controller boards on the left of the pictures for easy comparison...



    Reading GBAROM(0xFFFF) returns 0xe7ff when the piano is connected (the Guitar Hero Grip would return 0xf9ff) but this value changes in a most bizarre way when some keys are pressed. Pressing the right most key gives 0xa7ff. Pressing the next button instead gives 0xc7ff. Sounds simple binary eh? -No- since pressing both of the right most buttons at the same time gives 0xe7ff. I note that the values in the whole GBAROM(0x0000) to GBAROM(0xFFFF) range seem to be changing in a variable way. Things like SRAM(0) do not change on key presses.

    I am guessing that the component labelled Q1 in the bottom left of the 'key-board-board' is doing something clever.

    Any ideas? I am hoping someone can take a look at the circuit board and tell me what to try. I am also at a bit of a loss as to why this device is not already really popular in the community. It seems pretty great to me.

  2. bomb_dog

    bomb_dog Newbie

    Jan 31, 2008
    Spotted this in my local Morrisons supermarket for £8, got home and searched for homebrew as the game it comes with apparently isn't great.

    Doesn't look like anyone has used it yet for anything, would be a great investment if anyone can. Not got the skills to develop with it myself, but happy to test anything...!