working prototype

src/main.rs

@@ -0,0 +1,59 @@
+use hound::{self, WavWriter};
+use std::f32::consts::PI;
+use std::{fs, i16, io};
+
+const SAMPLE_RATE: f32 = 44100.0;
+const MORSE_FREQ: f32 = 600.0;
+const UNIT_TIME: f32 = 100.0 / 1000.0; // IN MS
+const CHAR_TIME: f32 = 50.0 / 1000.0;
+
+const SPEC: hound::WavSpec = hound::WavSpec {
+    channels: 1,
+    sample_rate: 44100,
+    bits_per_sample: 16,
+    sample_format: hound::SampleFormat::Int,
+};
+
+fn write_freq(writer: &mut WavWriter<io::BufWriter<fs::File>>, freq: f32, duration: f32) {
+    let sample_count = (duration * SAMPLE_RATE).ceil() as i32;
+    for t in (0..sample_count).map(|x| x as f32 / SAMPLE_RATE) {
+        let sample = (t * freq * 2.0 * PI).sin();
+        let amplitude = i16::MAX as f32;
+        writer.write_sample((sample * amplitude) as i16).unwrap();
+    }
+}
+
+fn write_morse(filename: &str, morse: &str) {
+    let mut writer = hound::WavWriter::create(filename, SPEC).unwrap();
+
+    //for t in (0..sample_count).map(|x| x as f32 / SAMPLE_RATE) {
+    //    let sample = (t * MORSE_FREQ * 2.0 * PI).sin();
+    //    let amplitude = i16::MAX as f32;
+    //    writer.write_sample((sample * amplitude) as i16).unwrap();
+    //}
+
+    for c in morse.chars() {
+        // We give a margin of CHAR_TIME between dots and dashes
+        // and we give 1.5 * UNIT_TIME between characters
+        if c == '.' {
+            write_freq(&mut writer, MORSE_FREQ, UNIT_TIME);
+            write_freq(&mut writer, 0.0, CHAR_TIME);
+        } else if c == '-' {
+            write_freq(&mut writer, MORSE_FREQ, 3.0 * UNIT_TIME);
+            write_freq(&mut writer, 0.0, CHAR_TIME);
+        } else if c == ' ' {
+            write_freq(&mut writer, 0.0, 1.5 * UNIT_TIME);
+        } else {
+            panic!("The morse code given is not valid!");
+        }
+    }
+    write_freq(&mut writer, 0.0, UNIT_TIME); // End padding
+}
+
+fn main() {
+    // -.. .- -. .. ... ...
+
+    write_morse("morse_danish.wav", "-.. .- -. .. ... ....");
+    //write_freq(&mut writer, 350.0, 1.0);
+    //write_freq(&mut writer, 650.0, 1.0);
+}