correct wind calc & use dht22

main/meteo_task.c

@@ -11,77 +11,80 @@
 #include "ds18b20.h"
 #include "dht.h"
 #include "driver/gpio.h"
+#include "circbuf.h"
 
-static volatile uint32_t timestamp_ms = 0;
-static volatile uint32_t last_revolution_ts = 0;
+static volatile uint32_t timestamp = 0;
 
-#define RPM_BUFFER_LEN 10
-static volatile uint16_t rpm_buffer[RPM_BUFFER_LEN] = {};
-static volatile int rpm_buffer_next = 0;
-static volatile int num_valid_average = 0;
+#define RPS_BUFFER_LEN (60*10)
+static volatile uint16_t history[RPS_BUFFER_LEN] = {};
+static CircBuf rps_cb;
+
+static volatile float rpm_average = 0;
+static volatile float rpm_gust = 0;
+
+static volatile uint16_t cycle_count = 0;
+
+void calculate_wind();
 
 static void gpio_isr_handler(void *arg)
 {
-    uint32_t ts = timestamp_ms;
-    uint32_t cycle_ms = ts - last_revolution_ts;
-    last_revolution_ts = ts;
-
-    if (cycle_ms > 0xFFFF) {
-        cycle_ms = 0xFFFF;
-    }
-    rpm_buffer[rpm_buffer_next++] = (uint16_t) cycle_ms;
-    if (rpm_buffer_next == RPM_BUFFER_LEN) {
-        rpm_buffer_next = 0;
-    }
-    if (num_valid_average < RPM_BUFFER_LEN) {
-        num_valid_average++;
+    if (cycle_count < 0xFFFF) {
+        cycle_count++;
     }
 }
 
-float get_rpm() {
-    float res;
-    float current = (float)(timestamp_ms - last_revolution_ts);
-
-    if (num_valid_average > 0) {
-        // we write num_valid_average only from here, so its safe to assume it stays nonzero
-        float average = 0;
-        int pos = rpm_buffer_next;
-        for (int i = 0; i < num_valid_average; i++) {
-            average += (float) rpm_buffer[pos];
-            pos--;
-            if (pos < 0) {
-                pos = RPM_BUFFER_LEN - 1;
-            }
-        }
-        average /= (float) (num_valid_average);
-
-        // now we have ms per revolution
-
-        if (current > average * 10.0f) {
-            // if wind stopped, invalidate the averaging buffer and use the current time from the last hall event
-            res = current;
-            num_valid_average = 0; // invalidate average results
-        } else {
-            res = average;
-        }
-    } else {
-        res = current;
-    }
-
-    float rpm = 60000.0f / res;
-    if (rpm < 1) {
-        rpm = 0;
-    }
-    return rpm; // RPM
-}
-
-void hw_timer_callback1(void *arg)
+void hw_timer_callback1s(void *arg)
 {
-    timestamp_ms++;
+    timestamp++;
+
+    // FIXME use a freertos queue and pass this to a thread!
+    if (cbuf_full(&rps_cb)) {
+        cbuf_pop_back(&rps_cb, NULL);
+    }
+    cbuf_push(&rps_cb, (void*) &cycle_count);
+    cycle_count = 0;
+
+    calculate_wind();
 }
 
+void calculate_wind()
+{
+    // Wind speed is average from 10 minutes
+    // Gust is max 3-second average anywhere within the 10 minutes
+
+    float max_gust = 0;
+
+    uint32_t tenmin_sum = 0;
+    uint32_t numsecs = cbuf_count(&rps_cb);
+    uint16_t threesec1 = 0, threesec2 = 0;
+    for(size_t i = 0; i < numsecs; i++) {
+        uint16_t *slot = cbuf_ptr_nth(&rps_cb, i);
+        if (!slot) {
+            continue;
+        }
+
+        uint16_t slotval = *slot;
+        tenmin_sum += (uint32_t) slotval;
+
+        // gust is max avg from 3 seconds within the 10 minutes
+        uint32_t gust_sum = (uint32_t) threesec1 + (uint32_t) threesec2 + (uint32_t) slotval;
+        threesec1 = threesec2;
+        threesec2 = slotval;
+
+        float gust_avg = (float)gust_sum * (float)20.0f;
+        if (gust_avg > max_gust) {
+            max_gust = gust_avg;
+        }
+    }
+    rpm_gust = max_gust;
+    rpm_average = ((float)tenmin_sum / (float)numsecs) * 60.0f;
+}
+
+
 void meteo_task(void* pvParameters)
 {
+    cbuf_init(&rps_cb, (void*)history, RPS_BUFFER_LEN, 2); // uint16 fields
+
     // Try to unfuck GPIOs
     PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDI_U, FUNC_GPIO12);
     PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_GPIO13);
@@ -89,8 +92,8 @@ void meteo_task(void* pvParameters)
     PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDO_U, FUNC_GPIO15);
 
     // start timer used for timebase
-    hw_timer_init(hw_timer_callback1, NULL);
-    hw_timer_alarm_us(1000, true); // 1 ms timer
+    hw_timer_init(hw_timer_callback1s, NULL);
+    hw_timer_alarm_us(1000000, true); // 1s timer
 
     gpio_config_t io_conf;
     io_conf.intr_type = GPIO_INTR_POSEDGE;
@@ -107,11 +110,12 @@ void meteo_task(void* pvParameters)
         // this works ...
         ds_temp = ds18b20_measure_and_read(0, DS18B20_ANY);
 
-        if (!dht_read_float_data(DHT_TYPE_DHT11, 12, &dht_hum, &dht_temp)) {
+        if (!dht_read_float_data(DHT_TYPE_DHT22, 12, &dht_hum, &dht_temp)) {
             dht_hum = dht_temp = NAN;
         }
 
-        printf("Dallas: %.2f °C, DHT %.2f °C, %.1f %%r.H, HALL %.1f RPM\n", ds_temp, dht_temp, dht_hum, get_rpm());
+        printf("Dallas: %.2f °C, DHT %.2f °C, %.1f %%r.H, HALL avg %.1f RPM, gust %.1f RPM\n",
+               ds_temp, dht_temp, dht_hum, rpm_average, rpm_gust);
 
         vTaskDelay(pdMS_TO_TICKS(500));
     }