diff --git a/MockBand.ino b/MockBand.ino
index 3b3f96c..e3d6997 100644
--- a/MockBand.ino
+++ b/MockBand.ino
@@ -21,6 +21,17 @@
 #define SAMPLES_PER_MS (SAMPLES_PER_FRAME / UPDATE_INTERVAL_MS)
 #define SILENCE_SAMPLES (SAMPLES_PER_MS * SILENCE_INTERVAL_MS)
 
+#if USB_VID != 0x1bad
+#error USB_VID must be set to 0x1bad
+#endif
+
+#if USB_PID == 0x0004
+#define GUITAR
+#elif USB_PID == 0x0005
+#define DRUM
+#else
+#error USB_PID must be set to 4 (Guitar) or 5 (Drum)
+#endif
 
 InstrumentButtonState buttonState;
 
diff --git a/README.md b/README.md
index 72b39bb..a061525 100644
--- a/README.md
+++ b/README.md
@@ -32,10 +32,35 @@ I used the following:
 
 ![see standard.hh for pin connections](wii-rb-std.png)
 
-For a drum kit,
-orange is the kick pedal.
-Strum and whammy are not wired.
 
-If you are not using a whammy,
-you should probably ground that pin.
-I didn't, but you should. ;)
+## Drum Kit
+
+On the drum kit,
+
+* Orange: kick pedal
+* Solo Buttons: cymbals
+
+I think. I haven't been able to test this yet,
+but the Clone Hero wiki leads me to believe this is how it works.
+
+
+# Still To Do
+
+
+* 2x kick: needs its own input pin. Maps to button 5.
+* Drum pad modifier: looks like button 10 needs to be pressed when a drum pad is hit.
+* Drum cymbal modifier: I don't see a problem with using the solo pins for this, but I may need to also send button 11.
+* Hi Hat pedal: needs to be its own input pin. Looks like it maps to the second Y axis: the one I'm currently using to send frame rate.
+
+If I set this up correctly, it will use every input pin on the pro micro.
+
+Perhaps a smarter thing to do would be use the value of USB_PID
+to re-use the orange solo pin as the hi hat pedal,
+and the red solo pin as the 2x kick.
+
+The
+[Clone Hero Drum Mapping Guide](https://wiki.clonehero.net/books/guitars-drums-controllers/page/drum-mapping-guide)
+is super helpful.
+I'll need to hunt down a copy of Wii Rock Band 3
+(or maybe The Beatles?)
+in order to test this on an actual Wii.
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