Hello guys!
I am trying to program an ESP32 board to read an analog and digital values and display both on a webpage. The board is running in SoftAP mode meaning it acts both as a webserver and access point with its own network.
I managed to make it work with only the digital value (temperature) but I have issues getting it to run with both analog (pressure) and digital values.
I use ds18b20 sensor for temperature and a generic analog pressure sensor.
My code is this:
// Import required libraries
#include <WiFi.h>
#include <ESPAsyncWebServer.h>
#include <OneWire.h>
#include <DallasTemperature.h>
// Data wire is connected to GPIO 4
#define ONE_WIRE_BUS 4
// Setup a oneWire instance to communicate with any OneWire devices
OneWire oneWire(ONE_WIRE_BUS);
// Pass our oneWire reference to Dallas Temperature sensor
DallasTemperature sensors(&oneWire);
// Variables to store temperature values
String temperatureC = "";
String pressureValue ="";
// Float Vars to store pressure values - NEW
const int pressureInput1 = 5; //select the analog input pin for the pressure OIL
//const int pressureInput2 = A2; //select the analog input pin for the pressure of FUEL
const int pressureZero = 285.3; //analog reading of pressure transducer at 0psi
const int pressureMax = 4095; //analog reading of pressure transducer at 100psi
const int pressuretransducermaxPSI = 100; //psi value of transducer being used
//const int baudRate = 115200; //constant integer to set the baud rate for serial monitor
//const int sensorreadDelay = 250; //constant integer to set the sensor read delay in milliseconds
//Float pressureValue = 0; //variable to store the value coming from the pressure transducer
// Timer variables
unsigned long lastTime = 0;
unsigned long timerDelay = 300;
// Replace with your network credentials - CHANGED
const char *ssid = "MyESP32AP";
const char *password = "123456789";
// Create AsyncWebServer object on port 80
AsyncWebServer server(80);
// OIL PRESSURE
String ReadPressureValue() {
int pressureValueRead = analogRead(pressureInput1); //reads value from input pin and assigns to variable
float pressureValueActual = (((pressureValueRead - pressureZero) * pressuretransducermaxPSI) / (pressureMax - pressureZero)) / 14.504; //conversion equation to convert analog reading to psi
Serial.print(pressureValueActual, 2); //prints value from previous line to serial
Serial.println("psi"); //prints label to serial
}
String readDSTemperatureC() {
// Call sensors.requestTemperatures() to issue a global temperature and Requests to all devices on the bus
sensors.requestTemperatures();
float tempC = sensors.getTempCByIndex(0);
if (tempC == -127.00) {
Serial.println("Failed to read from DS18B20 sensor");
return "--";
} else {
Serial.print("Temperature Celsius: ");
Serial.println(tempC);
}
return String(tempC);
}
const char index_html[] PROGMEM = R"rawliteral(
<!DOCTYPE HTML><html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
html {
font-family: Arial;
display: inline-block;
margin: 0px auto;
text-align: center;
}
h2 { font-size: 3.0rem; }
p { font-size: 3.0rem; }
.units { font-size: 1.2rem; }
.ds-labels{
font-size: 1.5rem;
vertical-align:middle;
padding-bottom: 15px;
}
</style>
</head>
<body>
<h2>ESP32 SoftAP</h2>
<p>
<span class="ds-labels">Temperature Celsius</span><br>
<span id="temperaturec">%TEMPERATUREC%</span>
<sup class="units">°C</sup>
</p>
<p>
<span class="ds-labels">Pressure PSI</span><br>
<span id="pressure1">%pressureValue%</span>
<sup class="units">PSI</sup>
</p>
</body>
<script>
setInterval(function ( ) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("temperaturec").innerHTML = this.responseText;
}
};
xhttp.open("GET", "/temperaturec", true);
xhttp.send();
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("pressureValue").innerHTML = this.responseText;
}
};
xhttp.open("GET", "/pressureValue", true);
xhttp.send();
}, 50) ;
</script>
</html>)rawliteral";
// Replaces placeholder with DS18B20 values - NEW - pressure values too
String processor(const String& var) {
//Serial.println(var);
if (var == "TEMPERATUREC") {
return temperatureC;
}
else if (var == "pressureValue") {
return pressureValue;
}
return String();
}
void setup() {
// Serial port for debugging purposes
Serial.begin(115200);
Serial.println();
// Start up the DS18B20 library
sensors.begin();
//Serial.println(xPortGetCoreID());
temperatureC = readDSTemperatureC();
pressureValue = ReadPressureValue();
// Wi-Fi Soft AP start
WiFi.softAP(ssid, password);
// Print ESP Local IP Address
Serial.println(WiFi.localIP());
Serial.println();
Serial.print("IP address: ");
Serial.println(WiFi.softAPIP());
// Route for root / web page
server.on("/", HTTP_GET, [](AsyncWebServerRequest * request) {
request->send_P(200, "text/html", index_html, processor);
});
server.on("/temperaturec", HTTP_GET, [](AsyncWebServerRequest * request) {
request->send_P(200, "text/plain", temperatureC.c_str());
});
// Start server
server.begin();
}
void loop() {
if ((millis() - lastTime) > timerDelay) {
temperatureC = readDSTemperatureC();
pressureValue = ReadPressureValue();
lastTime = millis();
}
}
The above code compiles fine but the ESP goes into boot loop with the below error:
Rebooting...
ets Jun 8 2016 00:22:57
rst:0xc (SW_CPU_RESET),boot:0x16 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1044
load:0x40078000,len:10124
load:0x40080400,len:5856
entry 0x400806a8
Temperature Celsius: 23.25
-0.48psi
Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.
Core 1 register dump:
PC : 0x4000c3f0 PS : 0x00060330 A0 : 0x800d9c6b A1 : 0x3ffb1f00
A2 : 0x3ffc16f0 A3 : 0x00000000 A4 : 0x00000001 A5 : 0x3fe866cb
A6 : 0x00000000 A7 : 0x00000008 A8 : 0x00000000 A9 : 0x00000000
A10 : 0x00000002 A11 : 0x3f400974 A12 : 0x00000003 A13 : 0x0000ff00
A14 : 0x00ff0000 A15 : 0xff000000 SAR : 0x0000001c EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000000 LBEG : 0x400014fd LEND : 0x4000150d LCOUNT : 0xffffffff
ELF file SHA256: 0000000000000000
Backtrace: 0x4000c3f0:0x3ffb1f00 0x400d9c68:0x3ffb1f20 0x400d9d62:0x3ffb1f40 0x400d0bf8:0x3ffb1f60 0x400da562:0x3ffb1fb0 0x4008982e:0x3ffb1fd0
Any help would be appreciated.
Thanks in advance
