Add deep sleep and single-button UX with heartbeat LED

Replace the dual-switch handler with one button: short press cycles
patterns, long press arms deep sleep with ext1 GPIO wake. Add a
heartbeat LED task and fix the IMU test I2C pins to GPIO21/GPIO6.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main.py

@@ -8,6 +8,8 @@ from patterns import Patterns
 import gc
 import utime
 import machine
+import esp32
+import network
 import time
 import wifi
 import json
@@ -15,8 +17,21 @@ from p2p import p2p
 from machine import ADC, Pin, I2C
 from lsm6ds3 import LSM6DS3, is_lsm6ds3
 
+# XIAO ESP32-C3: deep-sleep GPIO wake only on GPIO 0-5 (header D0-D3).
+SW_PIN = 3            # D1 — switch to GND (short press cycle, long press sleep/wake)
+LED_PIN = 8           # D8 — onboard LED (active low)
+SLEEP_HOLD_MS = 2000
+SLEEP_RELEASE_WAIT_MS = 500  # wait after release before arming wake
+
 async def main():
+    sw = Pin(SW_PIN, Pin.IN, Pin.PULL_UP)
+    if machine.reset_cause() == machine.DEEPSLEEP_RESET:
+        print("woke from deep sleep, reason:", esp32.wake_reason())
+        while sw.value() == 0:
+            utime.sleep_ms(50)
+
     settings = Settings()
+    led = Pin(LED_PIN, Pin.OUT, value=1)
 
     patterns = Patterns(settings["led_pin"], settings["num_leds"], selected=settings["pattern"])
     if settings["color_order"] == "rbg": color_order = (1, 5, 3)
@@ -33,6 +48,14 @@ async def main():
             patterns.tick()
             await asyncio.sleep_ms(0)
 
+    async def heartbeat():
+        while True:
+            wdt.feed()
+            led.value(0)
+            await asyncio.sleep_ms(80)
+            led.value(1)
+            await asyncio.sleep_ms(920)
+
     async def system():
         adc = ADC(Pin(0), atten=ADC.ATTN_11DB)
         while True:
@@ -45,30 +68,66 @@ async def main():
                 print("%.3f V" % voltage)
                 await asyncio.sleep(1)
 
-    async def sw():
-        sw1 = machine.Pin(8, machine.Pin.IN, machine.Pin.PULL_UP)
-        sw2 = machine.Pin(9, machine.Pin.IN, machine.Pin.PULL_UP)
+    def enter_deep_sleep():
+        patterns.select("off")
+        patterns.sync()
+        utime.sleep_ms(100)
+        led.value(1)
+        for iface in (network.STA_IF, network.AP_IF):
+            wl = network.WLAN(iface)
+            if wl.active():
+                wl.active(False)
+        if sw.value() == 0:
+            print("button still pressed, not sleeping")
+            return
+        esp32.wake_on_ext1(pins=(sw,), level=esp32.WAKEUP_ANY_LOW)
+        print("deep sleep — press GPIO %d to wake" % SW_PIN)
+        machine.deepsleep()
 
+    async def prepare_deep_sleep():
+        print("release button to sleep")
+        while sw.value() == 0:
+            wdt.feed()
+            await asyncio.sleep_ms(50)
+        await asyncio.sleep_ms(SLEEP_RELEASE_WAIT_MS)
+        if sw.value() == 0:
+            print("button pressed again, sleep cancelled")
+            return
+        enter_deep_sleep()
+
+    async def switch_loop():
         p = ["on", "rainbow_cycle", "theater_chase",
                 "color_transition", "flicker",
                 "bidirectional_scanner"]
-        
+
         pattern_index = 0
+        press_start = None
+        sleep_pending = False
 
         print(p)
-        pressed1 = 0
-        pressed2 = 0
         while True:
-            if sw1.value() == 0:
-                patterns.select(p[pattern_index])
-                print(p[pattern_index])
-                pattern_index = pattern_index + 1
-                if pattern_index > len(p)-1:
-                    pattern_index = 0
-                print("pressed 1")
-            if sw2.value() == 0:
-                patterns.select("off")
-            await asyncio.sleep_ms(200)
+            if sleep_pending:
+                await prepare_deep_sleep()
+                sleep_pending = False
+                press_start = None
+                continue
+
+            if sw.value() == 0:
+                if press_start is None:
+                    press_start = utime.ticks_ms()
+                elif utime.ticks_diff(utime.ticks_ms(), press_start) >= SLEEP_HOLD_MS:
+                    sleep_pending = True
+                    press_start = None
+            else:
+                if press_start is not None:
+                    held = utime.ticks_diff(utime.ticks_ms(), press_start)
+                    if 50 < held < SLEEP_HOLD_MS:
+                        patterns.select(p[pattern_index])
+                        print(p[pattern_index])
+                        pattern_index = (pattern_index + 1) % len(p)
+                press_start = None
+
+            await asyncio.sleep_ms(50)
 
     telemetry = {
         "voltage": 0.0,
@@ -171,18 +230,20 @@ async def main():
                 print("IMU read error:", e)
             await asyncio.sleep_ms(200)
 
+    wdt = machine.WDT(timeout=10000)
+    wdt.feed()
+
     w = web(settings, patterns, telemetry)
     print(settings)
     # start the server in a bacakground task
     print("Starting")
     server = asyncio.create_task(w.start_server(host="0.0.0.0", port=80))
-    wdt = machine.WDT(timeout=10000)
-    wdt.feed()
 
     asyncio.create_task(tick())
+    asyncio.create_task(heartbeat())
     asyncio.create_task(p2p(settings, patterns))
     asyncio.create_task(system())
-    asyncio.create_task(sw())
+    asyncio.create_task(switch_loop())
     if imu_sensor is not None:
         asyncio.create_task(imu_loop())
         

test/lsm6ds3_test.py

@@ -5,7 +5,7 @@ from lsm6ds3 import LSM6DS3, is_lsm6ds3
 
 
 # XIAO ESP32C3 default I2C pins: SDA=GPIO6 (D4), SCL=GPIO7 (D5)
-i2c = I2C(0, scl=Pin(23), sda=Pin(22), freq=400000)
+i2c = I2C(0, scl=Pin(20), sda=Pin(21), freq=400000)
 
 
 def scan_i2c():