Fix issues with higher speeds

CoolNamesAllTaken · Nov 1, 2020 · dca1f4d · dca1f4d
1 parent de46491
commit dca1f4d
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Showing 3 changed files with 7 additions and 5 deletions.
diff --git a/code/radar_speed_sign/include/hb100.hh b/code/radar_speed_sign/include/hb100.hh
@@ -9,7 +9,7 @@ class HB100 {
     public:
         // sad sad, these are exposed because I need to hit them in an ISR
         volatile uint32_t last_pulse_period{0};
-        volatile uint32_t last_pulse_ms{0};
+        volatile uint32_t last_pulse_us{0};
 
         HB100(){}
 

diff --git a/code/radar_speed_sign/src/hb100.cpp b/code/radar_speed_sign/src/hb100.cpp
@@ -1,7 +1,7 @@
 #include "hb100.hh"
 
 uint16_t HB100::calc_speed() {
-    uint16_t curr_speed = 31360 / last_pulse_period / 1000; // V = Fd / 31.36, Fd = 1 / last_pulse_period[s]
+    uint16_t curr_speed = 31360 / last_pulse_period; // V = Fd / 31.36, Fd = 1 / last_pulse_period[s]
     _speed_buf[_speed_buf_index] = curr_speed;
     _speed_buf_index++;
     if (_speed_buf_index >= SPEED_BUF_SIZE) {

diff --git a/code/radar_speed_sign/src/main.cpp b/code/radar_speed_sign/src/main.cpp
@@ -21,7 +21,7 @@
 #define ENCODER_STEPS_PER_NOTCH 1
 
 
-volatile uint32_t last_pulse_ms = millis(); // [ms] time of last radar pulse
+volatile uint32_t last_pulse_us = micros(); // [ms] time of last radar pulse
 volatile uint32_t last_pulse_period = 0; // [ms] time between last two falling edges from radar
 
 LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_WIDTH_CHARS, LCD_HEIGHT_LINES);
@@ -38,8 +38,8 @@ void timer1_isr() {
  * Interrupt handler that triggers on falling pulses from HB100 radar
  **/
 void radar_isr() {
-  hb100.last_pulse_period = millis() - hb100.last_pulse_ms;
-  hb100.last_pulse_ms = millis();
+  hb100.last_pulse_period = micros() - hb100.last_pulse_us;
+  hb100.last_pulse_us = micros();
 }
 
 void setup() {
@@ -72,6 +72,8 @@ void loop() {
     // Serial.print("HB100 last pulse period: ");
     // Serial.println(hb100.last_pulse_period);
     // Serial.print("Calculated speed: ");
+    Serial.print(hb100.last_pulse_period);
+    Serial.print("    ");
     Serial.println(hb100.calc_speed());
     seven_seg.write(hb100.calc_speed());
     delay(10);