docs docs docs

README.md

@@ -150,7 +150,7 @@ in the code!
 | --- | --- |
 | TX0 | no connection |
 | RX1 | no connection |
-| 2 | 2x kick |
+| 2 | 2x kick / hat (see below) |
 | 3 | green |
 | 4 | red |
 | 5 | yellow |
@@ -163,10 +163,30 @@ in the code!
 | 14 | no connection |
 | 15 | blue cymbal |
 | 18 | yellow cymbal |
-| 19 | hi hat pedal |
+| 19 | hi hat pedal (see below) |
 | 20 | green cymbal |
 | 21 | no connection |
 
+### Pedals
+
+If you only have one pedal,
+wire it to pin 7.
+
+If you have two pedals,
+wire them to 7 and 2.
+
+If you have three pedals,
+wire them to 7, 2, and 19.
+
+Wii Rock Band 3
+only looks at the 2x kick pin:
+it provides a checkbox to reassign this to the high hat.
+Clone Hero
+will use both the 2x kick and the hi hat.
+Maybe there is some other game that uses this too.
+
+
+
 
 # Bugs / Not Yet Implemented
 

docs/tech-notes.md

@@ -1,3 +1,12 @@
+Technical Notes
+===============
+
+It took me a lot of time digging around the Internet to find some of this stuff.
+I'm writing down the highlights here,
+so that when original sources fall off the net,
+hopefully at least my notes will still be around.
+
+
 Sample Rate
 -----------
 
@@ -77,3 +86,52 @@ but the `rbdrum2midi` program looks at these bytes to detect hits.
 I set them to 127 when a hit is detected on the digital pin.
 
 Sending these values does not seem to cause problems with my Wii games.
+
+
+Product ID (PID)
+----------------
+
+Nicholas,
+who did the initial work on the guitar,
+suggested that PID 0x0005 would get the sketch working as drums.
+And that was correct:
+this works great on 
+Wii Rock Band 1 and 
+Wii LEGO Rock Band.
+
+But it fails in frustrating ways on
+Wii Rock Band 3:
+the yellow and blue pads don't navigate menus,
+and cymbals aren't detected.
+
+The fix was setting the USB PID to 0x3110.
+
+
+Drum Velocity
+--------
+
+I split the 12 "reserved" bytes from Nicholas's 
+`struct InstrumentButtonState`
+into 4 bytes of I-Don't-Know, 4 bytes of velocity,
+and 4 more bytes of I-Don't-Know.
+Whenever a pad is hit,
+I send 127 on the corresponding velocity.
+
+I did this because a program called `rbdrum2midi`
+ignores the button press events,
+and looks only at the velocity values.
+
+None of the Wii games I have
+seem to care what these values are set to.
+
+
+References
+=========
+
+The most valuable sources of information I found were:
+
+* [Nicholas Angle's reverse-engineering write-up](https://www.niangames.com/articles/reverse-engineering-rockband-guitar-controllers)
+* [Nicholas Angle's guitar controller program](https://github.com/NianZo/WiiGuitarController)
+* [Clone Hero Wiki: Drum Mapping Guide](https://wiki.clonehero.net/books/guitars-drums-controllers/page/drum-mapping-guide)
+* [rbdrum2midi source code](https://github.com/rbdrum2midi/rbdrum2midi)
+