""" VCNL4040 Assistive Switch (JSON-compatible, crash-resistant, beginner-friendly) Drop this file in CIRCUITPY as code.py. Features: - Loads settings from config.json (safe fallback if missing/corrupt). - Safe proximity reads with automatic re-initialization on I2C errors. - Persistent OFF (boot button) stored in microcontroller.nvm. - NeoPixel feedback for ON / OFF and temporary trigger feedback. - Debug prints that show the proximity and which key(s) were pressed. - Beginner-friendly comments throughout. """ # ------------------------ # Imports # ------------------------ import time import json import board import busio import usb_hid import neopixel import microcontroller from digitalio import DigitalInOut, Pull from adafruit_hid.keyboard import Keyboard from adafruit_hid.keycode import Keycode from adafruit_hid.mouse import Mouse import adafruit_vcnl4040 # ------------------------ # USER SAFETY / BEHAVIOR TOGGLE # ------------------------ USE_CONFIG = True # ------------------------ # Default configuration (safe defaults) # ------------------------ DEFAULT_CONFIG = { "proximity_threshold": 10, "key_press_duration_seconds": 0.1, "loop_delay_seconds": 0.05, "only_closer_trigger": True, "enable_debug_prints": True, "enable_neopixel_feedback": True, "neopixel_color_rgb": [0, 255, 0], "hold_key_until_proximity_change": False, "debounce_time_ms": 200, "key_action": {"type": "single_key", "keys": ["SPACE"]}, "mouse_action": {"type": "none", "scroll_amount": 1}, "enable_on_off_switch": True, "button_debounce_time_ms": 300, "on_state_neopixel_color_rgb": [0, 255, 0], "off_state_neopixel_color_rgb": [255, 0, 0], "delta_trigger": 6, # NEW: how much above baseline triggers "baseline_window": 30 # NEW: how many readings to average } # ------------------------ # Load config.json (if present and allowed) # ------------------------ config = {} if USE_CONFIG: try: with open("config.json", "r") as f: config = json.load(f) merged = DEFAULT_CONFIG.copy() merged.update(config) config = merged print("Loaded config.json.") except Exception as e: print("Could not load config.json, using defaults. Error:", e) config = DEFAULT_CONFIG.copy() else: print("USE_CONFIG is False — using built-in defaults.") config = DEFAULT_CONFIG.copy() # ------------------------ # Map string names to Keycode objects # ------------------------ keycode_map = {} for name in dir(Keycode): if not name.startswith("_"): try: keycode_map[name] = getattr(Keycode, name) except Exception: pass # ------------------------ # Convert JSON key list to actual Keycode objects # ------------------------ raw_keys = config.get("key_action", {}).get("keys", ["SPACE"]) ACTION_KEYCODES = [] for k in raw_keys: kk = keycode_map.get(k.upper()) if kk is None: print(f"Warning: Unknown key '{k}' in config.json; defaulting to SPACE") kk = Keycode.SPACE ACTION_KEYCODES.append(kk) # ------------------------ # Pull other config values into variables # ------------------------ PROXIMITY_THRESHOLD = int(config.get("proximity_threshold", 10)) KEY_PRESS_DURATION = float(config.get("key_press_duration_seconds", 0.1)) LOOP_DELAY = float(config.get("loop_delay_seconds", 0.05)) ONLY_CLOSER_TRIGGER = bool(config.get("only_closer_trigger", True)) ENABLE_DEBUG_PRINTS = bool(config.get("enable_debug_prints", True)) ENABLE_NEOPIXEL_FEEDBACK = bool(config.get("enable_neopixel_feedback", True)) NEOPIXEL_COLOR = tuple(config.get("neopixel_color_rgb", [0, 255, 0])) HOLD_KEY_UNTIL_PROXIMITY_CHANGE = bool(config.get("hold_key_until_proximity_change", False)) DEBOUNCE_TIME_MS = int(config.get("debounce_time_ms", 200)) MOUSE_ACTION = config.get("mouse_action", {}).get("type", "none") MOUSE_SCROLL_AMOUNT = int(config.get("mouse_action", {}).get("scroll_amount", 1)) ENABLE_ON_OFF = bool(config.get("enable_on_off_switch", True)) BUTTON_DEBOUNCE_MS = int(config.get("button_debounce_time_ms", 300)) ON_COLOR = tuple(config.get("on_state_neopixel_color_rgb", [0,255,0])) OFF_COLOR = tuple(config.get("off_state_neopixel_color_rgb", [255,0,0])) # NEW: relative trigger settings DELTA_TRIGGER = int(config.get("delta_trigger", 6)) BASELINE_WINDOW = int(config.get("baseline_window", 30)) # ------------------------ # Helpful startup print # ------------------------ print("Proximity switch starting with settings:") print(f" Threshold={PROXIMITY_THRESHOLD}, Key duration={KEY_PRESS_DURATION}s, Loop delay={LOOP_DELAY}s") print(f" Only closer trigger={ONLY_CLOSER_TRIGGER}, Debug={ENABLE_DEBUG_PRINTS}, NeoPixel={ENABLE_NEOPIXEL_FEEDBACK}") print(f" Action keys: {raw_keys}, Mouse action: {MOUSE_ACTION}, Hold until change: {HOLD_KEY_UNTIL_PROXIMITY_CHANGE}") print(f" Delta trigger={DELTA_TRIGGER}, Baseline window={BASELINE_WINDOW}") # ------------------------ # Hardware Initialization # ------------------------ keyboard = Keyboard(usb_hid.devices) mouse = Mouse(usb_hid.devices) try: pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.3, auto_write=False) except Exception as e: pixel = None print("NeoPixel not available:", e) # ------------------------ # IMPORTANT FIX: I2C FOR STEMMA QT # ------------------------ def init_i2c_and_sensor(): try: i2c = busio.I2C(board.SCL1, board.SDA1) # <-- CORRECT STEMMA QT PINS time.sleep(0.02) sensor = adafruit_vcnl4040.VCNL4040(i2c) time.sleep(0.02) return i2c, sensor except Exception as e: print("Sensor init failed:", e) return None, None i2c, sensor = init_i2c_and_sensor() if sensor is None: print("Warning: sensor not initialized at startup. Code will keep trying.") # Boot button setup if ENABLE_ON_OFF: try: button = DigitalInOut(board.BUTTON) button.pull = Pull.UP except Exception as e: button = None print("Boot button not available:", e) else: button = None try: persistent_off = (microcontroller.nvm[0] == 1) except Exception: persistent_off = False device_is_on = not persistent_off if ENABLE_NEOPIXEL_FEEDBACK and pixel is not None: pixel.fill(ON_COLOR if device_is_on else OFF_COLOR) pixel.show() if persistent_off: print("Device remembered OFF state. Press BOOT button to turn ON.") # ------------------------ # Safe read wrapper for VCNL4040 # ------------------------ def safe_read_proximity(timeout_ms=50): global i2c, sensor start = time.monotonic_ns() // 1_000_000 while True: if sensor is None: i2c, sensor = init_i2c_and_sensor() if sensor is None: time.sleep(0.05) return None try: return sensor.proximity except Exception as e: print("⚠️ Sensor read error:", e) try: try: i2c.deinit() except Exception: pass i2c, sensor = init_i2c_and_sensor() except Exception as e2: print("Re-init attempt failed:", e2) if (time.monotonic_ns() // 1_000_000) - start > timeout_ms: print("⏳ safe_read_proximity timeout — skipping this cycle") return None # ------------------------ # Boot button handler # ------------------------ last_button_press_ms = 0 def handle_boot_button(): global device_is_on, last_button_press_ms if button is None: return now_ms = time.monotonic_ns() // 1_000_000 if not button.value and (now_ms - last_button_press_ms) > BUTTON_DEBOUNCE_MS: device_is_on = not device_is_on last_button_press_ms = now_ms try: microcontroller.nvm[0] = 0 if device_is_on else 1 except Exception as e: print("Could not write persistent state to nvm:", e) if ENABLE_NEOPIXEL_FEEDBACK and pixel is not None: pixel.fill(ON_COLOR if device_is_on else OFF_COLOR) pixel.show() print("Device toggled:", "ON" if device_is_on else "OFF") if not device_is_on: try: keyboard.release_all() mouse.release_all() except Exception: pass # ------------------------ # MAIN LOOP VARIABLES # ------------------------ last_proximity = None last_trigger_time_ms = 0 DEBOUNCE_MS = int(DEBOUNCE_TIME_MS) # NEW: baseline tracking baseline_buffer = [] baseline = None # NEW: trigger state trigger_armed = True def now_ms(): return time.monotonic_ns() // 1_000_000 print("Ready. Entering main loop...") # ------------------------ # MAIN LOOP # ------------------------ while True: handle_boot_button() if not device_is_on: time.sleep(LOOP_DELAY) continue proximity = safe_read_proximity(timeout_ms=60) if proximity is None: time.sleep(LOOP_DELAY) continue # Update baseline buffer baseline_buffer.append(proximity) if len(baseline_buffer) > BASELINE_WINDOW: baseline_buffer.pop(0) # Compute baseline baseline = sum(baseline_buffer) / len(baseline_buffer) if last_proximity is None: last_proximity = proximity delta = proximity - baseline if ENABLE_DEBUG_PRINTS: print(f"Proximity: {proximity} (last: {last_proximity}) ARMED={trigger_armed} DELTA={delta:.1f} BASE={baseline:.1f}") # Arm trigger when we return to near baseline if delta < 1: # within 1 point of baseline trigger_armed = True # Trigger when delta exceeds threshold if trigger_armed and delta >= DELTA_TRIGGER: current_ms = now_ms() if (current_ms - last_trigger_time_ms) > DEBOUNCE_MS: if MOUSE_ACTION != "none": try: if MOUSE_ACTION == "scroll_up": mouse.move(wheel=MOUSE_SCROLL_AMOUNT) elif MOUSE_ACTION == "scroll_down": mouse.move(wheel=-MOUSE_SCROLL_AMOUNT) elif MOUSE_ACTION == "left_click": mouse.click(1) elif MOUSE_ACTION == "right_click": mouse.click(2) except Exception as e: print("Mouse action failed:", e) else: try: for kc, name in zip(ACTION_KEYCODES, raw_keys): keyboard.press(kc) if ENABLE_NEOPIXEL_FEEDBACK and pixel is not None: pixel.fill(NEOPIXEL_COLOR) pixel.show() time.sleep(KEY_PRESS_DURATION) keyboard.release_all() if ENABLE_NEOPIXEL_FEEDBACK and pixel is not None: pixel.fill(ON_COLOR) pixel.show() if ENABLE_DEBUG_PRINTS: print("Pressed keys:", ", ".join(raw_keys)) except Exception as e: print("Keyboard action failed:", e) last_trigger_time_ms = current_ms trigger_armed = False # disarm until it returns to baseline last_proximity = proximity time.sleep(LOOP_DELAY)