pulse threshold

src/stream.rs

@@ -2,6 +2,7 @@ use crate::offline::{Header, HDR_SIZE};
 use bracket_color::prelude::*;
 use clap::Parser;
 use dotenv::dotenv;
+use std::time::SystemTime;
 use std::{
     io::Write,
     sync::{Arc, Mutex},
@@ -9,6 +10,11 @@ use std::{
 };
 use v4l::video::Output;
 
+const MIN_CUTOFF: f64 = 26.0;
+const MAX_CUTOFF: f64 = 36.0;
+const MID_CUTOFF: f64 = (MIN_CUTOFF + MAX_CUTOFF) / 2.0;
+const RANGE_CUTOFF: f64 = MAX_CUTOFF - MIN_CUTOFF;
+
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
 struct Args {
@@ -87,6 +93,10 @@ fn main(streamer: Arc<Mutex<Streamer>>) -> anyhow::Result<()> {
     const WIDTH: usize = 288;
     const HEIGHT: usize = 384;
     println!("reading cutoff");
+    let start = SystemTime::now()
+        .duration_since(SystemTime::UNIX_EPOCH)
+        .unwrap()
+        .as_secs_f64();
     let cutoff = streamer.lock().unwrap().cutoff;
     let greyscale = !args.temperature || cutoff.is_none();
     let fourcc_repr = if greyscale {
@@ -143,7 +153,13 @@ fn main(streamer: Arc<Mutex<Streamer>>) -> anyhow::Result<()> {
         {
             if len == FRAME_LEN {
                 // read once per frame, can make it lower if need be
-                let cutoff = streamer.lock().unwrap().cutoff.unwrap_or(0.0);
+                // let cutoff = streamer.lock().unwrap().cutoff.unwrap_or(0.0);
+                let now = SystemTime::now()
+                    .duration_since(SystemTime::UNIX_EPOCH)
+                    .unwrap()
+                    .as_secs_f64();
+                let dt = now - start;
+                let cutoff = MID_CUTOFF + f64::sin(dt / 2.0) * 0.5 * RANGE_CUTOFF;
                 // swap the bytes, we are using LE, not BE, 16 bit grayscale
                 // possibly limitation of current v4l2loopback or v4l rust wrapper or libv4l2
                 for i in 0..FRAME_LEN / 2 {