Power off camera after boot and before deepsleep to conserve power

ThomasFarstrike · ThomasFarstrike · commit f9ee7a91cda1 · 2025-06-24T10:39:20.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,8 @@
+0.0.8
+=====
+- Move wifi icon to the right-hand side
+- Power off camera after boot and before deepsleep to conserve power
+
 0.0.7
 =====
 - Update battery icon every 5 seconds depending on VBAT/BAT_ADC
diff --git a/internal_filesystem/apps/com.micropythonos.camera/assets/camera_app.py b/internal_filesystem/apps/com.micropythonos.camera/assets/camera_app.py
@@ -138,6 +138,20 @@ def onStop(self, screen):
             webcam.deinit(self.cam)
         elif self.cam:
             self.cam.deinit()
+            # Power off, otherwise it keeps using a lot of current
+            try:
+                from machine import Pin, I2C
+                i2c = I2C(1, scl=Pin(16), sda=Pin(21))  # Adjust pins and frequency
+                #devices = i2c.scan()
+                #print([hex(addr) for addr in devices]) # finds it on 60 = 0x3C after init
+                camera_addr = 0x3C # for OV5640
+                reg_addr = 0x3008
+                reg_high = (reg_addr >> 8) & 0xFF  # 0x30
+                reg_low = reg_addr & 0xFF         # 0x08
+                power_off_command = 0x42 # Power off command
+                i2c.writeto(camera_addr, bytes([reg_high, reg_low, power_off_command]))
+            except Exception as e:
+                print(f"Warning: powering off camera got exception: {e}")
         print("camera app cleanup done.")
 
     def set_image_size(self):
diff --git a/internal_filesystem/boot_unix.py b/internal_filesystem/boot_unix.py
@@ -71,4 +71,28 @@ def catch_escape_key(indev, indev_data):
    # print(f"boot_unix: code={event_code}") # target={event.get_target()}, user_data={event.get_user_data()}, param={event.get_param()}
 #keyboard.add_event_cb(keyboard_cb, lv.EVENT.ALL, None)
 
+# On the Waveshare ESP32-S3-Touch-LCD-2, the camera is hard-wired to power on,
+# so it needs a software power off to prevent it from staying hot all the time and quickly draining the battery.
+# 1) Initialize camera, otherwise it doesn't reply to I2C commands:
+try:
+    from camera import Camera, GrabMode, PixelFormat, FrameSize, GainCeiling
+    cam = Camera(data_pins=[12,13,15,11,14,10,7,2],vsync_pin=6,href_pin=4,sda_pin=21,scl_pin=16,pclk_pin=9,xclk_pin=8,xclk_freq=20000000,powerdown_pin=-1,reset_pin=-1,pixel_format=PixelFormat.RGB565,frame_size=FrameSize.R240X240,grab_mode=GrabMode.LATEST)
+    cam.deinit()
+except Exception as e:
+    print(f"camera init for power off got exception: {e}")
+# 2) Soft-power off camera, otherwise it uses a lot of current for nothing:
+try:
+    from machine import Pin, I2C
+    i2c = I2C(1, scl=Pin(16), sda=Pin(21))  # Adjust pins and frequency
+    #devices = i2c.scan()
+    #print([hex(addr) for addr in devices]) # finds it on 60 = 0x3C after init
+    camera_addr = 0x3C # for OV5640
+    reg_addr = 0x3008
+    reg_high = (reg_addr >> 8) & 0xFF  # 0x30
+    reg_low = reg_addr & 0xFF         # 0x08
+    power_off_command = 0x42 # Power off command
+    i2c.writeto(camera_addr, bytes([reg_high, reg_low, power_off_command]))
+except Exception as e:
+    print(f"Warning: powering off camera got exception: {e}")
+
 print("boot_unix.py finished")
diff --git a/internal_filesystem/lib/mpos/ui/__init__.py b/internal_filesystem/lib/mpos/ui/__init__.py
@@ -382,6 +382,7 @@ def reset_cb(e):
     poweroff_label.center()
     def poweroff_cb(e):
         print("Power off action...")
+        remove_and_stop_current_activity() # make sure current app, like camera, does cleanup, saves progress, stops hardware etc.
         import sys
         if sys.platform == "esp32":
             #On ESP32, there's no power off but there is a forever sleep
@@ -548,6 +549,12 @@ def setContentView(new_activity, new_screen):
         end_time = utime.ticks_diff(utime.ticks_ms(), start_time)
         print(f"ui.py setContentView: new_activity.onResume took {end_time}ms")
 
+def remove_and_stop_current_activity():
+    current_activity, current_screen = screen_stack.pop()  # Remove current screen
+    if current_activity:
+        current_activity.onPause(current_screen)
+        current_activity.onStop(current_screen)
+        current_activity.onDestroy(current_screen)
 
 def back_screen():
     print("back_screen() running")
@@ -556,11 +563,7 @@ def back_screen():
         print("Warning: can't go back because screen_stack is empty.")
         return False  # No previous screen
     #close_top_layer_msgboxes() # would be nicer to "cancel" all input events
-    current_activity, current_screen = screen_stack.pop()  # Remove current screen
-    if current_activity:
-        current_activity.onPause(current_screen)
-        current_activity.onStop(current_screen)
-        current_activity.onDestroy(current_screen)
+    remove_and_stop_current_activity()
     prev_activity, prev_screen = screen_stack[-1] # load previous screen
     print("loading prev_screen with animation")
     lv.screen_load_anim(prev_screen, lv.SCR_LOAD_ANIM.OVER_RIGHT, 500, 0, True) #  True means delete the old screen, which is fine as we're going back and current_activity.onDestroy() was called
