feat: velocity profiles

Cargo.lock

@@ -772,7 +772,7 @@ dependencies = [
 
 [[package]]
 name = "geode_piano"
-version = "0.2.1"
+version = "0.3.0"
 dependencies = [
  "byte-slice-cast 1.2.2",
  "cortex-m",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "geode_piano"
-version = "0.2.1"
+version = "0.3.0"
 edition = "2021"
 license = "GPL-3.0-only"
 

README.md

@@ -44,7 +44,7 @@ but is harder to set up.
 
 ### with debug probe
 
-- Install `probe-rs`.
+- Install `probe-rs-tools` (`cargo install probe-rs-tools --locked`).
 - Follow the wiring instructions in the [Pico Getting Started Guide](https://datasheets.raspberrypi.com/pico/getting-started-with-pico.pdf), at _Appendix A: Using Picoprobe_ in the Picoprobe Wiring section.
     You only need to wire GND, SWCLK and SWDIO.
 - If you are using a second Pico as a debug probe,

src/bin/piano_firmware.rs

@@ -28,7 +28,7 @@ use embassy_rp::i2c;
 use embassy_rp::peripherals::USB;
 use embassy_rp::usb::{Driver, InterruptHandler};
 use geode_piano::matrix;
-use geode_piano::matrix::KeyMatrix;
+use geode_piano::matrix::{KeyMatrix, VelocityProfile};
 use geode_piano::midi;
 use geode_piano::usb::usb_task;
 use geode_piano::{blinky, pin_array, pins, unwrap};
@@ -445,7 +445,13 @@ async fn piano_task(pin_driver: pins::TransparentPins) {
     ];
 
     let mut mat = KeyMatrix::new(col_pins, row_pins, keymap);
-    mat.scan(pin_driver).await;
+    mat.scan(
+        pin_driver,
+        matrix::Config {
+            velocity_prof: VelocityProfile::Heavy,
+        },
+    )
+    .await;
 }
 
 bind_interrupts!(struct Irqs {

src/matrix.rs

@@ -3,7 +3,7 @@
 use crate::midi;
 use crate::pins;
 use crate::unwrap;
-use core::cmp::min;
+use core::cmp::{max, min};
 use embassy_rp::gpio;
 use embassy_time::{Duration, Instant, Ticker};
 
@@ -14,6 +14,38 @@ pub enum NormalState {
     NC,
 }
 
+/// Profile to map from key press duration to MIDI velocity.
+/// https://www.desmos.com/calculator/mynk7thhzp
+pub enum VelocityProfile {
+    Linear,
+    Heavy,
+    Light,
+}
+
+fn velocity_light(us: u64) -> u8 {
+    if us <= 60000 {
+        min(127, (135000 - us * 6 / 5) / 1000) as u8
+    } else {
+        (127 - min(us, 240000) / 4000 - 60) as u8
+    }
+}
+
+fn velocity_heavy(us: u64) -> u8 {
+    if us <= 17000 {
+        ((113000 - us) / 1000) as u8
+    } else {
+        ((127000 - min(us, 190000) / 2 - 22000) / 1000) as u8
+    }
+}
+
+fn velocity_linear(us: u64) -> u8 {
+    max(127000 - (us as i32), 0) as u8
+}
+
+pub struct Config {
+    pub velocity_prof: VelocityProfile,
+}
+
 /// Task to handle pedals in MIDI
 ///
 /// `norm_open` represents a normally open switch
@@ -63,7 +95,7 @@ impl<const N_ROWS: usize, const N_COLS: usize> KeyMatrix<N_ROWS, N_COLS> {
         }
     }
 
-    pub async fn scan(&mut self, mut pin_driver: pins::TransparentPins) {
+    pub async fn scan(&mut self, mut pin_driver: pins::TransparentPins, config: Config) {
         for i in pin_driver.pins {
             unwrap(pin_driver.set_input(i)).await;
             unwrap(pin_driver.set_pull(i, gpio::Pull::Up)).await;
@@ -89,7 +121,7 @@ impl<const N_ROWS: usize, const N_COLS: usize> KeyMatrix<N_ROWS, N_COLS> {
         loop {
             let profile: bool = counter == 0;
             counter += 1;
-            counter %= 500;
+            counter %= 5000;
             let prof_start = Instant::now();
             let mut prof_time_last_col = prof_start;
             let mut prof_dur_col = Duration::from_ticks(0);
@@ -121,16 +153,16 @@ impl<const N_ROWS: usize, const N_COLS: usize> KeyMatrix<N_ROWS, N_COLS> {
                         midi::KeyAction::N2(note) => {
                             if key_active {
                                 if note_first[note as usize].is_some() && !note_on[note as usize] {
-                                    // millisecond duration of keypress
+                                    // microsecond duration of keypress
                                     let dur =
-                                        note_first[note as usize].unwrap().elapsed().as_millis();
+                                        note_first[note as usize].unwrap().elapsed().as_micros();
-                                    let velocity: u8 = if dur <= 60 {
+                                    let velocity = match config.velocity_prof {
-                                        (127 - dur * 6 / 5) as u8
+                                        VelocityProfile::Heavy => velocity_heavy(dur),
-                                    } else {
+                                        VelocityProfile::Linear => velocity_linear(dur),
-                                        (127 - min(dur, 240) / 4 - 60) as u8
+                                        VelocityProfile::Light => velocity_light(dur),
                                     };
                                     defmt::debug!(
-                                        "{} velocity {} from dur {}ms",
+                                        "{} velocity {} from dur {}us",
                                         note,
                                         velocity,
                                         dur

src/midi/mod.rs

@@ -213,7 +213,7 @@ impl From<EndpointError> for Disconnected {
     }
 }
 
-static MIDI_QUEUE: Channel<ThreadModeRawMutex, MidiMsg, 3> = Channel::new();
+static MIDI_QUEUE: Channel<ThreadModeRawMutex, MidiMsg, 10> = Channel::new();
 
 /// Handle sending MIDI until connection breaks
 pub async fn midi_session<'d, T: Instance + 'd>(

src/usb.rs

@@ -50,7 +50,7 @@ pub async fn usb_task(
     let mut config = Config::new(0xdead, 0xbeef);
     config.manufacturer = Some("dogeystamp");
     config.product = Some("Geode-Piano MIDI keyboard");
-    config.serial_number = Some("0.2.1");
+    config.serial_number = Some("0.3.0");
     config.max_power = 100;
     config.max_packet_size_0 = 64;