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--- en:iot-open:practical:hardware:sut:stm32:emb4_1 [2024/04/22 17:40] – [Prerequisites] ktokarz
+++ en:iot-open:practical:hardware:sut:stm32:emb4_1 [2024/04/22 17:56] (current) – [Result validation] ktokarz
@@ Line 38: / Line 38: @@
 #include <DallasTemperature.h>
 </code>
-<note important>Also, remember to add the LCD handling library, as present in the EMB9 scenario, unless you decide to use another output device.</note>
+<note important>Also, remember to add the LCD handling library, as present in the STM_9 scenario, unless you decide to use another output device.</note>
 === Step 2 ===
 Declare the 1-Wire GPIO bus pin, 1-Wire communication handling object, sensor proxy and a variable to store readings:
 <code c>
-#define ONE_WIRE_BUS 6
+#define ONE_WIRE_BUS D0
 static OneWire oneWire(ONE_WIRE_BUS);
 static DallasTemperature sensors(&oneWire);
@@ Line 55: / Line 55: @@
   sensors.begin();
 </code>
 === Step 4 ===
 Read the data:
 <code c>
+  sensors.requestTemperatures();
   if (sensors.getDeviceCount()>0)
   {
     tempDS = sensors.getTempCByIndex(0);
-  }
-  else
-  {
-    // Sensors not present (broken?) or 1-wire bus error
   }
 </code>
@@ Line 75: / Line 71: @@
   * ''sensors.getAddress(sensorAddress, index)'' - reads device address given by ''uint8_t index'' and stores it in ''DeviceAddress sensorAddress''.
-The library can make non-blocking calls, which can also be implemented using timers, as presented in the scenario [[en:iot-open:practical:hardware:sut:esp32:adv1_1|]].
 ==== Result validation ====
 The observable temperature is usually within the range of 19-24C. If you find the temperature much higher, check your code, and if that is okay, please contact our administrator to inform us about the faulty AC.
+===== FAQ =====
+**I've got constant readings of value 85.0. What to do?**: Check if GPIO is OK (should be D0), check if you initialised controller class and call the function ''sensors.requestTemperatures();''. Give the OneWire bus and the sensor some recovery time (at least 250ms) between consecutive readings.
 <WRAP noprint>

en/iot-open/practical/hardware/sut/stm32/emb4_1.1713807627.txt.gz · Last modified: 2024/04/22 17:40 by ktokarz