Websocket reconnect after sleep mode

[Stumpy_L]

I'm working on a greenhouse monitor, currently I have a BME280 module connected to a ESP32 Dev board, this unit will be battery powered. In the house I have another ESP32 Dev board with a 3.5" TFT display. I connect both to my house WiFi router.

I have the monitor connect to the internet to get NTP time as well as I can send the BME values to ThinkSpeak. In order to keep that connection I used a websocket to also send the values to the base unit. This is my first websocket project, I found a good tutorial with the codes on YouTube, where else? The monitor is set as the server and the base the client. Although I would think that the base should be the server so I could have multiple monitors, clients, sending values to the base but that's another conversation.

Using the examples, I have gotten it all to work fine with one problem. To save battery life I put the monitor to sleep, so I lose the websocket connection. I have seen online people suggest heartbeats and adding java script to reconnect, that's beyond my knowledge, I have not done any Java script.

I came up with a crude and not very efficient way to reconnect. The monitor goes to sleep for 5 minutes, will be longer when I get this working, I wake it up for 1 minute. In the base's loop function I added a timer to keep trying to reconnect every 30 seconds. That works although after an hour or so the base gets hung up, again not the best way to do this. It does show me that is what I need to do, detect that I am no longer connected then try to reconnect.

Looking at the code below at the beginning of the loop function is my timer, I have commented out the if statement I was trying different parameters in websocket libraries, I'm also not very good at determining what I can use in the libraries.

So that's the question, what is the best way to reconnect to the server after it has gone to sleep and then woke back up?

Thanks for all comments and suggestions
John

Code: [Select all] [Expand/Collapse]

1.  
2. // Changed controller to ESP32
3. // Added websocket client
4.  
5. #include <SPI.h>
6. #include <TFT_eSPI.h> // Hardware-specific library
7. #include <WebServer.h>
8. #include <WebSocketsClient.h>
9. #include <ArduinoJson.h>
10.  
11. TFT_eSPI tft = TFT_eSPI();       // Invoke custom library
12.  
13. //==== Defining Variables
14.  
15. unsigned char text;
16. //char text[6] = "";
17. String inTemp, inHum, outTemp = "", outHum;
18. extern uint8_t SmallFont[];
19. extern uint8_t BigFont[];
20. extern uint8_t SevenSegNumFont[];
21.  
22. int x, y;
23.  
24. int currentPage = 0; //, selectedUnit;
25. int selectedUnit = 0;
26.  
27. char grnHouseTemp[20] = " "; // Greenhouse Temperature number
28. char grnHouseHum[20] = " "; // Greenhouse Humidity number
29. long int start_time = millis();
30. long int read_time = 4800; // time between reading Greenhouse data
31. int grnHouseRead = 0; // bit that system is reading Greenhouse status
32. float  grnHouse_Temp = 0; // Greenhouse temp
33. float  grnHouse_Hum = 0; // Greenhouse humdity
34. float  grnHouse_Press = 0; // Greenhouse pressure
35. boolean newData = false;
36.  
37.     // temporary array for use when parsing
38. const byte numChars = 64;
39. char receivedChars[numChars];
40. char tempChars[numChars];  
41.  
42.   // For Greenhouse
43. char temp_str1[25];
44. char humd_str1[25];
45. char prss_str1[25];
46. char Hour_strl[25];
47. char Min_strl[25];
48. char Batt_strl[25];
49.  
50. // Incoming data
51. struct incomingData {
52.  float In_Temp;
53.  float In_Prss;
54.  float In_Humd;
55.  int   In_Hour;
56.  int   In_Min;
57.  float Batt_Lvl;
58. }myincomingDataStructure;
59.  
60. // data from Greenhouse
61. struct dataStruct1 {
62.  float H1_Temp;
63.  float H1_Prss;
64.  float H1_Humd;
65.  float H1_Batt;
66. }myDataStructure1;
67.  
68. long int touchTime = 0; // time sceen was last touched
69. long int scrnSavTime = 60000; // Screen saver display time
70. int scrnSavOn = 0; //In screen saver mode
71. const int backLite = 53;
72.  
73. // WiFi
74. const char* ssid = "my_ssid"; // Wifi SSID
75. const char* password = "my_password"; //Wi-FI Password
76. WebSocketsClient webSocket; // websocket client class instance
77. StaticJsonDocument<120> doc; // Allocate a static JSON document
78. long int socket_Time = millis();
79. long int socket_Delay = 30000;
80.  
81. const String pin_stat = doc["PIN_Status"]; // String variable tha holds LED status
82. float Gh1_t = 1.1; // Float variable that holds temperature
83. float Gh1_h = 2.2; // Float variable that holds Humidity
84. float Gh1_p = 3.3; // Float variable that holds Pressure
85. float Gh1_b = 4.4; // Float variable that holds Battery Voltage
86. int Gh1_hr = 5; // integer for current hour
87. int Gh1_mn = 6; // integer for current minute
88.  
89. void setup() {
90.   Serial.begin(115200);
91.  // Serial.println("Start Setup");
92.  
93. // TFT setup
94.  
95.   tft.init();
96.   tft.fillScreen(TFT_BLACK); //clears screen, sets to Black
97.   tft.setRotation(1);  // rotates screen 180' for landscape mode
98.  
99.   currentPage = 0; // Indicates that we are at Home Screen
100.   selectedUnit = 0; // Indicates the selected unit for the first example, cms or inches
101.  
102.    // Draw intial screen
103.      drawHomeScreen();
104.    //drawGreenhouse1();  // Draws the Greenhouse 1 Status screen
105.    
106.   touchTime = millis(); // start touch time
107.  
108.  // Connect to local WiFi
109.   WiFi.begin(ssid, password);
110.   Serial.begin(115200);
111.   while (WiFi.status() != WL_CONNECTED) {
112.     Serial.print(".");
113.     delay(500);
114.   }
115.   Serial.println();
116.   Serial.print("IP Address: ");
117.   Serial.println(WiFi.localIP()); // Print local IP address
118.  
119.   //address, port, and URL path
120.   webSocket.begin("192.168.1.175", 81, "/");
121.   // webSocket event handler
122.   webSocket.onEvent(webSocketEvent);
123.   // if connection failed retry every 5s
124.   webSocket.setReconnectInterval(5000);
125.  
126. } // end void setup
127.  
128.  
129. void loop() {
130.  
131. if(millis() > socket_Time + socket_Delay){
132. //if(!connectFailedCb()){  
133.    //address, port, and URL path
134.   webSocket.begin("192.168.1.175", 81, "/");
135.   // webSocket event handler
136.   webSocket.onEvent(webSocketEvent);
137.   // if connection failed retry every 5s
138.   webSocket.setReconnectInterval(5000);
139.  
140.   socket_Time = millis();
141. } // end if(millis() > socket_Time + socket_Delay)
142.    webSocket.loop(); // Keep the socket alive
143.  
144.   // To get raw touch screen coordinates
145.  /*
146.       uint16_t x, y;
147.       tft.getTouchRaw(&x, &y);
148.       Serial.printf("x: %i     ", x);
149.       Serial.printf("y: %i     ", y);
150.       Serial.printf("z: %i \n", tft.getTouchRawZ());
151.       delay(250);
152. */
153.  
154.    display_cntrl(); // display screen controls
155.  
156.  
157. } // end void loop
158.  
159.  
160. // drawHomeScreen - Menu page
161.  
162.  // drawHomeScreen() {
163. void drawHomeScreen() {
164.   // Draws Home Screen
165.    tft.fillScreen(TFT_BLACK); //clears screen, sets to Black
166.  
167. // Prints the title on the screen
168.   tft.setCursor(80, 70);
169.   tft.setTextColor(TFT_WHITE);
170.   tft.setTextSize(3);
171.   tft.print("Greenhouse Monitor");
172.  
173.   // Draws the red line under the title
174.   tft.drawFastHLine(60, 100, 350, TFT_RED);
175.  
176.  
177.   // Button - Greenhouse page
178.  
179.   tft.fillRoundRect(140, 150, 210, 40, 25, TFT_BLUE);
180.   tft.drawRoundRect(140, 150, 210, 40, 25, TFT_WHITE);
181.   tft.setCursor(170, 160);
182.   tft.setTextColor(TFT_WHITE);
183.   tft.setTextSize(2);
184.   tft.print("Greenhouse");
185.  
186.  } // end void drawHomeScreen
187.  
188. void drawGreenhouse1() {
189.   // Draws Report Setup screen
190.   yield();
191. //  Serial.println("In drawGreenhouse1");
192.   // Sets the background color of the screen to black
193.   tft.fillScreen(TFT_BLACK);
194.  
195.  // Back to Home button
196.  
197.   tft.fillRoundRect(30, 20, 50, 30, 10, TFT_BLUE);
198.   tft.drawRoundRect(30, 20, 50, 30, 10, TFT_WHITE);
199.   tft.setCursor(40, 27);
200.   tft.setTextColor(TFT_WHITE);
201.   tft.setTextSize(2);
202.   tft.print("<-");
203.  
204.   tft.setCursor(100, 30);
205.   tft.setTextColor(TFT_WHITE);
206.   tft.setTextSize(1);
207.   tft.print("Back to Main Menu");
208.  
209.   // Prints the title on the screen
210.   tft.setCursor(80, 70);
211.   tft.setTextColor(TFT_WHITE);
212.   tft.setTextSize(3);
213.   tft.print("Greenhouse Status");
214.  
215.   // Draws the red line under the title
216.   tft.drawFastHLine(90, 100, 320, TFT_RED);
217.  
218.  // Label - Temperature
219.  
220.   tft.fillRect(20, 120, 90, 40, TFT_CYAN);
221.   tft.drawRect(20, 120, 90, 40, TFT_WHITE);
222.  // tft.fillRect(0, 0, 90, 40, TFT_CYAN);
223.  // tft.drawRect(5, 3, 90, 40, TFT_WHITE);
224.   tft.setCursor(32, 130);
225.   tft.setTextColor(TFT_BLACK);
226.   tft.setTextSize(2);
227.   tft.print("Temp = ");
228.   //tft.drawCentreString("Temp = ",120, 70, 4);
229.  
230.  // Label Humidity #
231.  
232.   tft.fillRect(20, 190, 90, 40, TFT_CYAN);
233.   tft.drawRect(20, 190, 90, 40, TFT_WHITE);
234.   tft.setCursor(35, 200);
235.   tft.setTextColor(TFT_BLACK);
236.   tft.setTextSize(2);
237.   tft.print("Hum = ");
238.  
239.  // Label Pressure
240.  
241.   tft.fillRect(240, 120, 100, 40, TFT_CYAN);
242.   tft.drawRect(240, 120, 100, 40, TFT_WHITE);
243.   tft.setCursor(250, 130);
244.   tft.setTextColor(TFT_BLACK);
245.   tft.setTextSize(2);
246.   tft.print("Press = ");
247.  
248.   // Label Update Time
249.  
250.   tft.fillRect(240, 190, 100, 40, TFT_CYAN);
251.   tft.drawRect(240, 190, 100, 40, TFT_WHITE);
252.   tft.setCursor(250, 200);
253.   tft.setTextColor(TFT_BLACK);
254.   tft.setTextSize(2);
255.   tft.print("Time = ");
256.  
257.   // Label Battery Level
258.  
259.   tft.fillRect(20, 260, 135, 40, TFT_CYAN);
260.   tft.drawRect(20, 260, 135, 40, TFT_WHITE);
261.   tft.setCursor(35, 270);
262.   tft.setTextColor(TFT_BLACK);
263.   tft.setTextSize(2);
264.   tft.print("Battery = ");
265.  
266. } // end of drawGreenhouse1
267.  
268. void webSocketEvent(WStype_t type, uint8_t * payload, size_t length) {
269.   //Serial.println("webSocketEvent");
270.  
271.   if (type == WStype_TEXT)
272.   {
273.     DeserializationError error = deserializeJson(doc, payload); // deserialize incoming Json String
274.     if (error) { // Print erro msg if incomig String is not JSON formated
275.       Serial.print(F("deserializeJson() failed: "));
276.       Serial.println(error.c_str());
277.       return;
278.     }
279.    
280.     const float t = doc["Temp"]; // Float variable that holds temperature
281.     Gh1_t = t;
282.     const float h = doc["Hum"]; // Float variable that holds Humidity
283.     Gh1_h = h;
284.     const float p = doc["Press"]; // Float variable that holds pressure
285.     Gh1_p = p;
286.     const float b = doc["Batt"]; // Float variable that holds battery voltage
287.     Gh1_b = b;
288.     const int hr = doc["Hour"]; // Float variable that holds current hour
289.     Gh1_hr = hr;
290.     const int mn = doc["Min"]; // Float variable that holds current minute
291.     Gh1_mn = mn;
292.    
293.     // Print the received data for debugging
294.     //Serial.print(String(pin_stat));
295.     //Serial.print(String(t));
296.     //Serial.println(String(h));
297.     // Send acknowledgement
298.     // webSocket.sendTXT("OK");
299.        
300.   //  Serial.print("LED = ");
301.   //  Serial.print("\t");
302.   //  Serial.print(pin_stat);
303.   //  Serial.print("\t");
304.    
305.     Serial.print("Temp = ");
306.     Serial.print(t);
307.     Serial.print("\t");
308.  
309.     Serial.print("Pressure = ");
310.     Serial.print(p);
311.     Serial.print("\t");
312.    
313.     Serial.print("Humidity = ");
314.     Serial.println(h);
315.  
316.     Serial.print("Time = ");
317.     Serial.print(hr);
318.     Serial.print(":");
319.     Serial.print(mn);
320.     Serial.print("\t");
321.  
322.     Serial.print("Battery = ");
323.     Serial.println(b);
324.  
325.     Serial.println();
326.    
327.   } // end if (type == WStype_TEXT)
328. } // end void webSocketEvent
329.  

GeSHi © Codebox Plus Extension