From 2a78201a2dc923fdf7a34b33ca98e93231522eeb Mon Sep 17 00:00:00 2001
From: salty <salty@saltylab.local>
Date: Sat, 14 Mar 2026 13:01:04 -0400
Subject: [PATCH] fix: time-division multiplexing for 2-anchor collision
 avoidance

Each anchor only runs DW1000Ranging during its 50ms time slot.
Anchor 0 responds in even slots, anchor 1 in odd slots.
Prevents RF collisions that caused wild range readings.
---
 esp32/uwb_anchor/src/main.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/esp32/uwb_anchor/src/main.cpp b/esp32/uwb_anchor/src/main.cpp
index e423b6e..c9ae1ed 100644
--- a/esp32/uwb_anchor/src/main.cpp
+++ b/esp32/uwb_anchor/src/main.cpp
@@ -195,8 +195,21 @@ void setup(void) {
 
 /* ── Loop ───────────────────────────────────────────────────────── */
 
+/*
+ * Time-division multiplexing: 2 anchors share the same channel.
+ * Each anchor only responds during its time slot to avoid RF collisions.
+ * Slot duration = 50ms → each anchor gets 10 Hz effective rate.
+ * Anchor 0 responds during even slots, anchor 1 during odd slots.
+ */
+#define SLOT_MS  50
+#define NUM_ANCHORS_TOTAL  2
+
 void loop(void) {
     serial_poll();
     espnow_process();
-    DW1000Ranging.loop();
+
+    uint32_t slot = (millis() / SLOT_MS) % NUM_ANCHORS_TOTAL;
+    if (slot == ANCHOR_ID) {
+        DW1000Ranging.loop();
+    }
 }