A helpers.go

@@ -0,0 +1,51 @@
+package main
+
+import "image/color"
+
+type HSL struct {
+	H, S, L float64
+}
+
+func hueToRGB(v1, v2, h float64) float64 {
+	if h < 0 {
+		h += 1
+	}
+	if h > 1 {
+		h -= 1
+	}
+	switch {
+	case 6*h < 1:
+		return (v1 + (v2-v1)*6*h)
+	case 2*h < 1:
+		return v2
+	case 3*h < 2:
+		return v1 + (v2-v1)*((2.0/3.0)-h)*6
+	}
+	return v1
+}
+
+func (c HSL) ToRGB() color.RGBA {
+	h := c.H
+	s := c.S
+	l := c.L
+
+	if s == 0 {
+		// it's gray
+		return color.RGBA{R: uint8(l), G: uint8(l), B: uint8(l)}
+	}
+
+	var v1, v2 float64
+	if l < 0.5 {
+		v2 = l * (1 + s)
+	} else {
+		v2 = (l + s) - (s * l)
+	}
+
+	v1 = 2*l - v2
+
+	r := hueToRGB(v1, v2, h+(1.0/3.0))
+	g := hueToRGB(v1, v2, h)
+	b := hueToRGB(v1, v2, h-(1.0/3.0))
+
+	return color.RGBA{R: uint8(r * 256), G: uint8(g * 256), B: uint8(b * 256)}
+}

M main.go → main.go

@@ -104,14 +104,22 @@ closedConfig := config
 	closedConfig.eyeColor = color.RGBA{R: 0, G: 0, B: 0}
 	closed := eyes(eyes(leds, closedConfig, false), config, true)
 
+	color := HSL{H: 0.5, S: 1, L: 0.01}
 	for {
-		if rand.Float32() > 0.1 {
+		color.H += 0.01
+		if color.H > 1 {
+			color.H -= 1
+		}
+		config.eyeColor = color.ToRGB()
+		open = eyes(leds, config, false)
+		closed = eyes(eyes(leds, closedConfig, false), config, true)
+		if rand.Float32() > 0.025 {
 			device.WriteColors(open)
 		} else {
 			device.WriteColors(closed)
 		}
 
-		time.Sleep(time.Millisecond * 200)
+		time.Sleep(time.Millisecond * 50)
 	}
 
 }