shaun/pico-hcsr04
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Added first order filter to distance measurement to reduce noise.

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This commit is contained in:
Shaun Setlock
2023-01-02 12:04:57 -05:00
parent 551e8f9e30
commit e9f9ce5acb
1 changed files with 14 additions and 8 deletions
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22
main.py
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@@ -1,14 +1,11 @@
# Built-in's
import network import network
import rp2 import rp2
import time import time
import json import json
import machine import machine
from machine import Pin
# From PyPI
from umqtt.robust import MQTTClient from umqtt.robust import MQTTClient
import wifi_config
# From this project...
import mqtt_config import mqtt_config
from pico_funcs import read_cpu_temp, wlan_up, led_error_code from pico_funcs import read_cpu_temp, wlan_up, led_error_code
from hcsr04_funcs import read_hc_sr04 from hcsr04_funcs import read_hc_sr04
@@ -43,13 +40,17 @@ def main():
) )
# Create HC-SR04 # Create HC-SR04
trig = machine.Pin(TRIG_PIN, machine.Pin.OUT) trig = Pin(TRIG_PIN, Pin.OUT)
echo = machine.Pin(ECHO_PIN, machine.Pin.IN, machine.Pin.PULL_DOWN) echo = Pin(ECHO_PIN, Pin.IN, Pin.PULL_DOWN)
# Let's Go! # Let's Go!
if DEBUG: if DEBUG:
print("Enter main loop") print("Enter main loop")
# First Time flag allows the 1st order filter to be initialized.
first_time = True
FILTER_CONSTANT = 0.9
while True: while True:
# Loop Clean-Up and Prep # Loop Clean-Up and Prep
@@ -71,7 +72,12 @@ def main():
# HC-SR04 Reading. # HC-SR04 Reading.
try: try:
distance = read_hc_sr04(trig, echo) sensor_value = read_hc_sr04(trig, echo)
if not first_time:
distance = distance * FILTER_CONSTANT + (1 - FILTER_CONSTANT) * sensor_value
else:
distance = sensor_value
first_time = False
hc_sr04_ready = True hc_sr04_ready = True
except: except:
continue continue