Provide some debug output.

hostcontrol/Cargo.lock

@@ -1446,6 +1446,7 @@ dependencies = [
  "eframe",
  "egui",
  "env_logger",
+ "log",
  "nalgebra",
  "nalgebra-macros",
  "serialport",
@@ -1759,9 +1760,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.27"
+version = "0.4.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13dc2df351e3202783a1fe0d44375f7295ffb4049267b0f3018346dc122a1d94"
+checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
 [[package]]
 name = "mach2"

hostcontrol/Cargo.toml

@@ -11,3 +11,4 @@ nalgebra-macros = "^0.2.2"
 env_logger = "0.11.8"
 egui = "0.31.1"
 eframe = "0.31.1"
+log = "0.4.29"

hostcontrol/src/stage.rs

@@ -2,6 +2,7 @@
 
 use std::time::Duration;
 use thiserror::Error;
+use log::debug;
 
 fn new_camera_rotation(theta: f64) -> nalgebra::Matrix3<f64> {
     nalgebra::matrix![
@@ -55,6 +56,8 @@ pub type StageIOResult<T> = std::result::Result<T, StageIOError>;
 impl StageIO {
     pub fn new(port: &str, speed: u32) -> StageIOResult<Self> {
 	let serial = serialport::new(port, speed).timeout(Duration::from_secs(60)).open()?;
+	// TODO: read and discard initial characters; some devices like to be
+	// chatty on start-up.
 	Ok(Self { serial })
     }
 
@@ -71,10 +74,12 @@ impl StageIO {
     }
 
     // Send request and wait for response deliminated with a newline
-    fn send_request<S: AsRef<str>>(&mut self, command: S) -> StageIOResult<String> {
+    pub fn send_request<S: AsRef<str>>(&mut self, command: S) -> StageIOResult<String> {
+	debug!("->: {:?}", command.as_ref());
         self.serial.write_all(command.as_ref().as_bytes()).map_err(|e| StageIOError::Write(e))?;
-        let res = self.receive_until("\n")?;
-        Ok(res.trim().to_string())
+        let response = self.receive_until("\n")?;
+	debug!("<-: {:?}", response);
+        Ok(response.trim().to_string())
     }
 }