Merge pull request #68 from yeyeto2788/master

Addition of test timing script

Author: jposada202020

.gitignore

@@ -13,3 +13,4 @@ bundles
 .eggs
 dist
 **/*.egg-info
+venv

docs/examples.rst

@@ -6,3 +6,13 @@ Ensure your device works with this simple test.
 .. literalinclude:: ../examples/dht_simpletest.py
     :caption: examples/dht_simpletest.py
     :linenos:
+
+
+Time calibration advance test
+------------------------------
+
+Check what is the best time your sensor.
+
+.. literalinclude:: ../examples/dht_time_calibration_advance.py
+    :caption: examples/dht_time_calibration_advance.py
+    :linenos:

examples/dht_time_calibration_advance.py

@@ -0,0 +1,105 @@
+# SPDX-FileCopyrightText: 2021 yeyeto2788 for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+"""
+This script let's you check the best timing for you sensor as other people have face timing issues
+as seen on issue https://github.com/adafruit/Adafruit_CircuitPython_DHT/issues/66.
+
+By changing the variables values below you will be able to check the best timing for you sensor,
+take into account that by most datasheets the timing for the sensor are 0.001 DHT22 and
+0.018 for DHT11 which are the default values of the library.
+"""
+
+import json
+import time
+
+import board
+
+import adafruit_dht
+
+# Change the pin used below
+pin_to_use = "PG6"
+
+# Maximum number of tries per timing
+max_retries_per_time = 10
+# Minimum wait time from where to start testing
+min_time = 1500
+# Maximum wait time on where to stop testing
+max_time = 2000
+# Increment on time
+time_increment = 100
+
+# Variable to store all reads on a try
+reads = {}
+
+initial_msg = f"""
+\nInitializing test with the following parameters:
+
+- Maximum retries per waiting time: {max_retries_per_time}
+- Start time (ms): {min_time}
+- End time (ms): {max_time}
+- Increment time (ms): {time_increment}
+
+This execution will try to read the sensor {max_retries_per_time} times
+for {len(range(min_time, max_time, time_increment))} different wait times values.
+
+"""
+# Print initial message on the console.
+print(initial_msg)
+
+for milliseconds in range(min_time, max_time, time_increment):
+    # Instantiate the DHT11 object.
+    dhtDevice = adafruit_dht.DHT11(pin=getattr(board, pin_to_use))
+    # Change the default wait time for triggering the read.
+    # pylint: disable=protected-access
+    dhtDevice._trig_wait = milliseconds
+
+    # pylint: disable=protected-access
+    print(f"Using 'trig_wait' of {dhtDevice._trig_wait}")
+    # Reset the read count for next loop
+    reads_count = 0
+
+    # Create the key on the reads dictionary with the milliseconds used on
+    # this try.
+    if milliseconds not in reads:
+        reads[milliseconds] = {"total_reads": 0}
+
+    for try_number in range(0, max_retries_per_time):
+        try:
+            # Read temperature and humidity
+            temperature = dhtDevice.temperature
+            humidity = dhtDevice.humidity
+            read_values = {"temperature": temperature, "humidity": humidity}
+
+            if try_number not in reads[milliseconds]:
+                reads[milliseconds][try_number] = read_values
+
+            reads_count += 1
+        except RuntimeError as e:
+            time.sleep(2)
+        else:
+            time.sleep(1)
+
+    reads[milliseconds]["total_reads"] = reads_count
+
+    print(f"Total read(s): {reads[milliseconds]['total_reads']}\n")
+    dhtDevice.exit()
+
+# Gather the highest read numbers from all reads done.
+best_result = max([reads[milliseconds]["total_reads"] for milliseconds in reads])
+
+# Gather best time(s) in milliseconds where we got more reads
+best_times = [
+    milliseconds
+    for milliseconds in reads
+    if reads[milliseconds]["total_reads"] == best_result
+]
+print(
+    f"Maximum reads: {best_result}  out of {max_retries_per_time} with the "
+    f"following times: {', '.join([str(t) for t in best_times])}"
+)
+
+# change the value on the line below to see all reads performed.
+print_all = False
+if print_all:
+    print(json.dumps(reads))