Gold price alarm using ESP32-C3 0.42 OLED display – MicroPython

from machine import (Pin, I2C, deepsleep, reset_cause,
                     PWRON_RESET, HARD_RESET, WDT_RESET, DEEPSLEEP_RESET, SOFT_RESET)
from time import sleep_ms, ticks_ms, ticks_diff
from Secrets import SSID, PASSWORD
import esp32
import micropython
import ssd1306
import urequests
import network
import gc

micropython.alloc_emergency_exception_buf(100)   # readable errors inside IRQs

# ---------------- Configuration ----------------
PRICE_URL = 'https://api.gold-api.com/price/XAU'
HIGH_LIMIT = 4130.0         # alarm when price >  this value
LOW_LIMIT = 4000.0          # alarm when price < this value FETCH_INTERVAL = 300000 # ms in deep sleep between price requests ALARM_DURATION_MS = 10000 # how long the alarm beeps WIFI_TIMEOUT_MS = 15000 SHORT_MAX_MS = 500 # shorter than this = short press LONG_MIN_MS = 3000 # this or longer = long press IGNORE_AFTER_MS = 300 # ignore bounce events after a press finished # ---------------- Startup info ---------------- RESET_CAUSES = { PWRON_RESET: "Power on / brownout", HARD_RESET: "Hard reset / crash", WDT_RESET: "Watchdog", DEEPSLEEP_RESET: "Wake from deep sleep", SOFT_RESET: "Soft reset", } print("Reset cause:", RESET_CAUSES.get(reset_cause(), reset_cause())) gc.collect() print("Free RAM:", gc.mem_free()) # ---------------- Hardware ---------------- i2c = I2C(0, scl=Pin(6), sda=Pin(5)) oled = ssd1306.SSD1306_I2C(72, 40, i2c) # 0.42" OLED: 9 chars x 5 lines alarm_pin = Pin(10, Pin.OUT, value=0) # buzzer or LED Button = Pin(3, Pin.IN, Pin.PULL_UP) # pressed = 0 # Deep sleep wake-up works on a level, so wake when the pin is LOW esp32.wake_on_gpio((Button,), esp32.WAKEUP_ALL_LOW) # ---------------- State ---------------- alarm_muted = False # toggled by a short press alarm_stop = False # set by a long press: end the alarm now busy = False # a button press is being handled last_end = 0 # time when the last press finished # ---------------- Helpers ---------------- def oled_print(text): """Print text on the OLED, wrapping every 9 characters (max 5 lines).""" oled.fill(0) for line in range(5): chunk = text[line * 9:(line + 1) * 9] if not chunk: break oled.text(chunk, 0, line * 8) oled.show() def go_to_sleep(): """Turn off the outputs and enter deep sleep. Never returns.""" alarm_pin.off() # Uncomment the line below to turn off the display during deep sleep. # This saves a little more battery power. # oled.poweroff() deepsleep(FETCH_INTERVAL) # ---------------- Button handling ---------------- def on_short_press(): global alarm_muted alarm_muted = not alarm_muted print("Short press: alarm", "muted" if alarm_muted else "active") def on_long_press(): global alarm_stop alarm_stop = True print("Long press: alarm ended") def BTN_PRESS_FUNC(pin): """Runs outside the interrupt (scheduled), so sleep and print are safe.""" global busy, last_end alarm_pin.off() # no constant tone while the button is held start = ticks_ms() long_detected = False while pin.value() == 0: # measure press time if ticks_diff(ticks_ms(), start) >= LONG_MIN_MS:
            long_detected = True
            break
        sleep_ms(10)

    if long_detected:
        on_long_press()
        while pin.value() == 0:                   # wait for release
            sleep_ms(20)
    else:
        duration = ticks_diff(ticks_ms(), start)
        if duration < SHORT_MAX_MS:
            on_short_press()
        else:
            print("Ignored:", duration, "ms")     # between 500 ms and 3 s

    sleep_ms(50)                                  # let the release bounce finish
    last_end = ticks_ms()
    busy = False


def BTN_PRESS_HANDLER(pin):
    """IRQ handler: must be very short. It only schedules the real work."""
    global busy
    if busy or ticks_diff(ticks_ms(), last_end) < IGNORE_AFTER_MS:
        return                                    # bounce or stale event
    busy = True
    try:
        micropython.schedule(BTN_PRESS_FUNC, pin)
    except RuntimeError:                          # schedule queue is full
        busy = False


Button.irq(handler=BTN_PRESS_HANDLER, trigger=Pin.IRQ_FALLING)


# ---------------- Alarm ----------------
def run_alarm():
    """Beep for ALARM_DURATION_MS. Short press = mute/unmute, long press = end."""
    start = ticks_ms()
    while ticks_diff(ticks_ms(), start) < ALARM_DURATION_MS and not alarm_stop:
        if alarm_muted:
            alarm_pin.off()
        else:
            alarm_pin.value(not alarm_pin.value())   # toggle = beep
        sleep_ms(200)
    alarm_pin.off()


# ---------------- Wi-Fi and price ----------------
def connect_wifi(ssid, password, timeout_ms=WIFI_TIMEOUT_MS):
    """Connect to Wi-Fi. Return True on success, False on timeout."""
    wlan = network.WLAN(network.WLAN.IF_STA)
    wlan.active(True)
    if not wlan.isconnected():
        wlan.connect(ssid, password)
        oled_print("Connecting wifi!!!")
        print("Connecting wifi!!!")

    start = ticks_ms()
    while ticks_diff(ticks_ms(), start) < timeout_ms: if wlan.isconnected(): print("Wi-Fi connected:", wlan.ifconfig()) oled_print("Online!") return True sleep_ms(500) print("Wi-Fi not found!") return False def find_key(obj, target_key): """Recursively search for a key in a nested dict or list.""" if isinstance(obj, dict): if target_key in obj: return obj[target_key] items = obj.values() elif isinstance(obj, list): items = obj else: return None for item in items: result = find_key(item, target_key) if result is not None: return result return None def get_gold_price(url=PRICE_URL, target_key='price'): """Return the gold price as float, or None on any error.""" response = None try: gc.collect() # free RAM before the TLS connection response = urequests.get(url) if response.status_code != 200: print("HTTP error:", response.status_code) return None price = find_key(response.json(), target_key) if price is None: print("Key not found:", target_key) return None price = float(price) print("Gold Price (XAU/USD):", price) return price except Exception as e: print("Error fetching price:", e) return None finally: if response is not None: response.close() # ---------------- Main program ---------------- # Deep sleep ends with a reset, so this code runs once per wake-up. try: if connect_wifi(SSID, PASSWORD): price = get_gold_price() if price is not None: alarm_on = price > HIGH_LIMIT or price < LOW_LIMIT
            oled_print('GoldPrice{:9.2f}H{:8.2f}L{:8.2f}Alarm:{}'.format(
                price, HIGH_LIMIT, LOW_LIMIT, 'ON' if alarm_on else 'OFF'))
            if alarm_on:
                run_alarm()
                if alarm_stop:
                    oled_print("Alarm off")      # visitor ended the alarm
                    sleep_ms(2000)
            else:
                sleep_ms(5000)                   # keep the values visible for 5 s
        else:
            oled_print("Price error")
            sleep_ms(3000)
    else:
        oled_print("No Wi-Fi!")
        sleep_ms(3000)
    go_to_sleep()
except KeyboardInterrupt:
    print("KeyboardInterrupt occurred!")