From: Martin Mareš <mj@ucw.cz>
Date: Sat, 17 Jan 2026 17:50:11 +0000 (+0100)
Subject: X-mas: Binary clock
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=7b01d72f790149a27989fd9775bad56796a6e516;p=home-hw.git

X-mas: Binary clock
---

diff --git a/xmas-lights/daemon/xmas-lights.c b/xmas-lights/daemon/xmas-lights.c
index c8d5aa4..e9f2222 100644
--- a/xmas-lights/daemon/xmas-lights.c
+++ b/xmas-lights/daemon/xmas-lights.c
@@ -264,6 +264,41 @@ static void clock_year(uint t)
 	}
 }
 
+static void clock_blank(void)
+{
+	memset(lights, 0, sizeof(lights));
+}
+
+static void clock_time(uint h, uint m)
+{
+	memset(lights, 0, sizeof(lights));
+
+	uint x = (h << 6) | m;
+	const uint NBITS = 11;
+	const uint BITSIZE = 5;
+	const uint BITGAP = 6;
+	const uint BIGGAP_AT = 6;
+	const uint BIGGAP_ENLARGE = 10;
+	const uint BITOFF = (NPIX_NUM_LEDS - NBITS * BITSIZE - (NBITS - 1) * BITGAP - BIGGAP_ENLARGE) / 2;
+
+	for (uint i=0; i < NBITS; i++) {
+		uint j = BITOFF + (BITSIZE + BITGAP) * i;
+		if (i >= BIGGAP_AT)
+			j += BIGGAP_ENLARGE;
+		for (uint k = 0; k < BITSIZE; k++) {
+			if (x & (1 << i)) {
+				lights[j+k][0] = 0;
+				lights[j+k][1] = 0;
+				lights[j+k][2] = 255;
+			} else {
+				lights[j+k][0] = 64;
+				lights[j+k][1] = 64;
+				lights[j+k][2] = 64;
+			}
+		}
+	}
+}
+
 static void clock_tick(void)
 {
 	struct timeval tv;
@@ -272,14 +307,23 @@ static void clock_tick(void)
 		sleep(1);
 		return;
 	}
-	uint t = (uint) tv.tv_sec + 1;
+	time_t t = tv.tv_sec + 1;
 	usleep(1000000 - tv.tv_usec);
 
-	uint midnight = 1767222000;
+#if 0
+	// Countdown to New Year
+	time_t midnight = 1767222000;
 	if (t < midnight)
-		clock_countdown(midnight - t);
+		clock_countdown((uint)(midnight - t));
 	else
 		clock_year(2026);
+#else
+	struct tm *tm = localtime(&t);
+	if (tm->tm_hour >= 9 && tm->tm_hour < 16)
+		clock_blank();
+	else
+		clock_time(tm->tm_hour, tm->tm_min);
+#endif
 }
 
 /*** Main ***/