added code for fluorescent light demo

2 files changed, 134 insertions, 1 deletions

diff --git a/README.adoc b/README.adoc
index a1195ec..15cfd55 100644
--- a/README.adoc
+++ b/README.adoc
@@ -1,7 +1,10 @@
 == Various Arduino Snippets
 
 Every now and then I create a small Arduino (test) project. I think I should
-publish the stuff here.
+publish the stuff here — this is mostly cargo cult code that has been hammered
+into some semi-working form.
 
 Currently in this repository:
 
+lighting/strobe.ino::
+    The code behind my https://xenoworld.de/2017/01/18/blink.html[fluorescent light demo].
diff --git a/lighting/strobe.ino b/lighting/strobe.ino
new file mode 100644
index 0000000..eccc1c4
--- /dev/null
+++ b/lighting/strobe.ino
@@ -0,0 +1,130 @@
+// PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
+byte LED_A = 3;
+byte LED_B = 5;
+
+#define STROBE_STATE_SLOW 1
+#define STROBE_STATE_FAST 2
+#define STROBE_STATE_NONE 3
+
+class Strobe {
+    byte slow, fast;
+    byte state;
+    byte led;
+    boolean on;
+    unsigned long next = 0;
+
+public:
+    boolean stopped = false;
+
+    Strobe(byte l, byte s, byte f) {
+        state = STROBE_STATE_SLOW;
+        led = l;
+        slow = s;
+        fast = f;
+        on = false;
+    }
+
+    boolean run() {
+        if (next > 0 && (millis() < next)) {
+            return false;
+        }
+
+        switch(state) {
+        case STROBE_STATE_SLOW:
+            on = !on;
+            analogWrite(led, on ? 255 : 0);
+            if(on) {
+                next = millis() + 10;
+                return false;
+            } else {
+                next = millis() + 300 + random(0, 300);
+            }
+            if(--slow <= 0) {
+                state = STROBE_STATE_FAST;
+            }
+            return false;
+        case STROBE_STATE_FAST:
+            on = !on;
+            analogWrite(led, on ? 255 : 0);
+            if(on) {
+                next = millis() + 10;
+                return false;
+            } else {
+                next = millis() + 75 + random(0, 75);
+            }
+            if(--fast <= 0) {
+                state = STROBE_STATE_NONE;
+                on = false;
+            }
+            return false;
+        default:
+            if(!on) {
+                analogWrite(led, 255);
+                on = true;
+                stopped = true;
+                return true;
+            }
+        }
+    }
+};
+
+void setup() {
+    pinMode(2, INPUT_PULLUP);
+    Serial.begin(9600);
+}
+
+void flash(byte led, byte duration)
+{
+    analogWrite(led, 255);
+    delay(duration);
+    analogWrite(led, 0);
+}
+
+void fade(byte led, byte stepDuration, byte stepSize, boolean in) {
+    if(in) {
+        for (int fadeValue = 0 ; fadeValue <= 255; fadeValue+=stepSize) {
+            analogWrite(led, fadeValue);
+            delay(stepDuration);
+        }
+    } else {
+        for (int fadeValue = 255 ; fadeValue >=0;  fadeValue-=stepSize) {
+            analogWrite(led, fadeValue);
+            delay(stepDuration);
+        }
+    }
+}
+
+void fade(byte led, byte stepDuration, boolean in)
+{
+    fade(led, stepDuration, 1, in);
+}
+
+unsigned long lastMillis;
+
+void loop() {
+    delay(1000);
+
+    Strobe s1 = Strobe(3, random(1,4), random(2, 6));
+    Strobe s2 = Strobe(5, random(1,4), random(2, 6));
+
+    while(!(s1.stopped && s2.stopped)) {
+        if(lastMillis > millis()) {
+            lastMillis = millis();
+            return;
+        }
+        s1.stopped ? : s1.run();
+        s2.stopped ? : s2.run();
+        lastMillis = millis();
+    }
+
+
+    delay(2500);
+
+    analogWrite(LED_A, 0);
+    analogWrite(LED_B, 0);
+
+    Serial.println(lastMillis);
+    Serial.println(millis());
+}
+
+