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feat(vl53l1x): Add proximity alert example with buzzer. #337

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Merged
Kaanoz-en merged 2 commits into from
Mar 30, 2026
Merged

feat(vl53l1x): Add proximity alert example with buzzer. #337

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feat(vl53l1x): Add proximity alert example with buzzer.
Mar 30, 2026
55691fc
fix(vl53l1x): Address review comments on proximity alert example.
Mar 30, 2026
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45 changes: 45 additions & 0 deletions lib/vl53l1x/examples/proximity_alert.py
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Original file line number Diff line number Diff line change
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"""Proximity alert using VL53L1X distance sensor and buzzer.

Beeps the buzzer when an object is detected within 200 mm. The pitch
increases as the object gets closer.
"""

from time import sleep_ms

from machine import I2C, Pin
from pyb import Timer
from vl53l1x import VL53L1X

DISTANCE_THRESHOLD_MM = 200

# Sensor configuration
i2c = I2C(1)
tof = VL53L1X(i2c)

# Buzzer initialisation
buzzer_tim = Timer(1, freq=1000)
buzzer_ch = buzzer_tim.channel(4, Timer.PWM, pin=Pin("SPEAKER"))
buzzer_ch.pulse_width_percent(0)

try:
while True:
distance = tof.read()
print("Distance: {} mm".format(distance))

if distance < DISTANCE_THRESHOLD_MM:
# Frequency ranging from 1500 (really close) to 500 (at 200mm)
freq = 1500 - (distance * 5)
# Security limits
freq = max(500, min(1500, freq))

buzzer_tim.freq(freq)
buzzer_ch.pulse_width_percent(50)
else:
buzzer_ch.pulse_width_percent(0)

Comment on lines +24 to +39
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Copilot AI Mar 30, 2026

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tof.read() can raise OSError("VL53L1X data ready timeout") (see lib/vl53l1x/vl53l1x/device.py:_ensure_data). If that happens while the buzzer is on, this script will exit without silencing it. Consider using a try: ... finally: (or catching Exception) around the loop to always set the buzzer duty back to 0 before exiting.

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@Kaanoz-en Kaanoz-en Mar 30, 2026

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This is an excellent point, I had handled the KeyboardInterrupt to prevent the PWM from running indefinitely, but I completely missed the potential OSError from the I2C bus timeouts. Moving the cleanup code to a finally: block is the perfect way to guarantee the buzzer is silenced no matter how the script exits. I'm updating the structure right away.

sleep_ms(50)

except KeyboardInterrupt:
pass
finally:
buzzer_ch.pulse_width_percent(0)
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