Issue with integrating sensor + WIFI

[AggelosK]

Hello. I've came across an issue whiel trying to connect my sensor with my esp32s board.

Code:

Code: [Select all] [Expand/Collapse]

1. #include <Arduino.h>
2. #include <freertos/FreeRTOS.h>
3. #include <freertos/task.h>
4. #include <dht.h>
5. #include <HTTPClient.h>
6. #include <WiFi.h>
7. #include <WiFiMulti.h>
8. #include <WiFiClientSecure.h>
9. #include <WebSocketsClient.h>
10. #include <ArduinoJson.h>
11.  
12. HTTPClient http;
13.  
14.  
15. WiFiMulti WiFiMulti;
16.  
17. WebSocketsClient webSocket;
18. TaskHandle_t readerHandle;
19.  
20. namespace JSON {
21.     class serializer {
22.     public:
23.         static String serializeRequestData(const char* key1, int val1, const char* key2, int val2);
24.     };
25.     class deserializer {
26.     public:
27.         static DynamicJsonDocument deserializeData(const char* input);
28.     };
29. }
30.  
31. DynamicJsonDocument JSON::deserializer::deserializeData(const char* input) {
32.     DynamicJsonDocument doc(256);
33.     DeserializationError error = deserializeJson(doc, input);
34.     if (error) {
35.         Serial.print("deserializeJson() failed: ");
36.         Serial.println(error.c_str());
37.     }
38.     return doc;
39. };
40.  
41. String JSON::serializer::serializeRequestData(const char* key1, int val1, const char* key2, int val2) {
42.     DynamicJsonDocument doc(256);
43.     String JSONData;
44.     if(key1 && val1) {
45.         doc[key1] = val1;
46.     }
47.  
48.     if(key2 && val2) {
49.         doc[key2] = val2;
50.     }
51.     serializeJson(doc, JSONData);
52.     return JSONData;
53. }
54.  
55. using namespace JSON;
56.  
57. DHT dht(26, DHT11);
58.  
59.  
60. [[noreturn]] void reader(void *pvParameters) {
61.     while (true) {
62.         if (WiFiClass::status() == WL_CONNECTED) {
63.             int hum = dht.readTemperature();
64.             int temp = dht.readTemperature();
65.             Serial.printf("Task 1 Reads %d\n", hum);
66.         }
67.     }
68. }
69.  
70.  
71. void setup() {
72.     xTaskCreate(reader, "reader", 4048, nullptr, 1, &readerHandle);
73.     Serial.begin(9600);
74.     pinMode(2, OUTPUT);
75.     pinMode(26, OUTPUT); // DHT 11
76.     dht.begin();
77.     WiFi.mode(WIFI_AP_STA);
78.     WiFi.enableLongRange(true);
79.     WiFi.softAP("ESP-32-Server", "12345678910");
80.     WiFi.begin("ssid", "pass");
81.  
82.     while (WiFiClass::status() != WL_CONNECTED) {
83.         Serial.println("Connecting..");
84.         delay(500);
85.     }
86.     Serial.printf("[WS]: Connected to %s\n", WiFi.SSID().c_str());
87.  
88. }
89.  
90. void loop() {
91. }
92.  

GeSHi © Codebox Plus Extension

First of all, the issue im facing is that the sensor occasionally reads the maximum value for a signed 32-bit integer which indicates an error. Ive tried altering the delay - Even to 5000 but that doesnt seem to be the case. Nevertheless, when i removed the WiFi connecting code (CHECK BELOW), it worked without any issues - even in 500s read rate. I acknowledge that i am allocating enough memory for the task and etc but i dont seem to understand this behaviour. I would love for some help.
Regards,
Aggelos.

Wifi Code:

Code: [Select all] [Expand/Collapse]

1.  WiFi.mode(WIFI_AP_STA);
2.     WiFi.enableLongRange(true);
3.     WiFi.softAP("ESP-32-Server", "12345678910");
4.     WiFi.begin("ssid", "pass");
5.  
6.     while (WiFiClass::status() != WL_CONNECTED) {
7.         Serial.println("Connecting..");
8.         delay(500);
9.     }

GeSHi © Codebox Plus Extension

Console Output:

Code: [Select all] [Expand/Collapse]

1. Task 1 Reads 25
2. Task 1 Reads 2147483647
3. Task 1 Reads 2147483647
4. Task 1 Reads 2147483647
5. Task 1 Reads 2147483647
6. Task 1 Reads 25
7. Task 1 Reads 25
8. Task 1 Reads 25
9. Task 1 Reads 25

GeSHi © Codebox Plus Extension

[lbernstone]

Put dht.begin at the start of your reader function. Don't manually set the pinMode on that pin. Put a delay at the end of the while loop in reader.
If it still has problems, then we can troubleshoot.

[AggelosK]

Thank you for your reply. However, ive tried your solution and im still getting the same output.

Removed the pinMode setting for the DHT pin,

Code altered:

Code: [Select all] [Expand/Collapse]

1. [[noreturn]] void reader(void *pvParameters) {
2.     dht.begin(); //Changed location of the begin statement
3.     while (true) {
4.         if (WiFiClass::status() == WL_CONNECTED) {
5.             int hum = dht.readTemperature();
6.             int temp = dht.readTemperature();
7.             Serial.printf("Task 1 Reads %d\n", hum);
8.             vTaskDelay(pdMS_TO_TICKS(1000)); //should be rougly 1 second - Enough time
9.         }
10.     }
11. }
12.  
13. // . . .
14.  

GeSHi © Codebox Plus Extension

[lbernstone]

delay should be at the end of the while loop, not in the if. You need a delay on every pass here or else you are starving other processes (eg WiFi).
Do you actually need this to run continuously? The DHT is a slow device, and if it is unable to come up with a response, it may be giving you those negative numbers as an indication that it is timing out. Run it on a reasonable cycle that matches up with how frequently you will use the data.
I don't know much about the Adafruit library. I use UncleRus' drivers which are esp32 optimized, and allow you to pull both pieces of data in one query of the dht. It will give a clear error if it is unable to get a response from the dht.

[AggelosK]

Thank you for your response.

I intended to also add a vTaskDelay(pdMS_TO_TICKS(1000)) in the original code hwoever it still kept eventually showing wrong values. Positioning the taskcreation in the end still did not fix the issue. Nevertheless, i will take a look at the attached link.

[lbernstone]

I will recommend testing on https://wokwi.com . It lets you separate software from hardware issues more easily, and then you can share your example easily when you get a reproducible issue.

[AggelosK]

Thank you for your response.

I tried it but since it didnt have support for DHT11, i tried DHT22 and it worked perfectly. In the meantime, i tried with a different dht11 sensor however they both malfunctioned and produced the same wrong output. Should i consider that the sensor is way too slow and dht22 isnt?

Project: https://wokwi.com/projects/385810614370936833

[lbernstone]

A DHT22 is a thing closer to a USB power adapter than a Intel Core i5. They are made by many companies in China from a reference model, so you don't really know quite what you are getting in the package. Some will work quite perfectly, and may even have a brand name and a lot number on them. Some will be cheap junk, scraped off an old board and resold.

[AggelosK]

Yeah, true. Well m not sure what else do i have as a solution.


Pardon for my inactivity, i got a lot of stuff to accomplish.