From 28247cf74ab63c681dfc1491ebe2e993ace48b8a Mon Sep 17 00:00:00 2001
From: Simon Couball <s.couball@gmail.com>
Date: Tue, 11 Aug 2020 23:51:44 +0200
Subject: [PATCH] Control LED with period

---
 src/main.cpp | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 199b335..95d4c8e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -73,28 +73,37 @@ void loop()
     uint32_t period = 0;
     uint16_t rotations = 0;
 
+    uint16_t led_period = (uint16_t)-1;
+    uint16_t led_counter = led_period;
+
     while (1) {
         iterator++;
 
         uint8_t tacho_current = digitalRead(7);
 
+        /* Get number of loop iterations per fan revolution */
         if (!tacho_last && tacho_current) {
             if (tacho_counter == 0) {
                 tacho_counter = 1;
-                digitalWrite(2, LOW);
             } else {
                 tacho_counter = 0;
-                digitalWrite(2, HIGH);
                 period = iterator;
+                led_period = period / 3;
                 iterator = 0;
                 rotations++;
             }
+        }
+        tacho_last = tacho_current;
+
+        /* Emit strobe for LED */
+        led_counter--;
+        if (led_counter < 12) {
+            digitalWrite(2, HIGH);
+            if (!led_counter) {
+                led_counter = led_period;
+            }
         } else {
             digitalWrite(2, LOW);
         }
-
-        tacho_last = tacho_current;
-
-        delayMicroseconds(100);
     }  
 }