I am extremely new to working with sensors and Arduino and IoT equipment altogether. I am using an Arduino Uno. I need to use an ADXL345 sensor with an ESP8266 Wifi module for a project. The two devices work on their own just fine. But when I connect them together, with the Generic ESP8266 Module board, the ADXL345 does not get detected.

I am using the 2.5.0 version of the ESP8266 library as that's the only one that seems to work with both the ESP8266 and the ADXL345 sensor.

Below is my code -

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>

/* Assign a unique ID to this sensor at the same time */
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(12345);

char ssid[] = "ssid";   // your network SSID (name) 
char pass[] = "pass";   // your network password
int keyIndex = 0;            // your network key Index number (needed only for WEP)
WiFiClient  client;

void displayDataRate(void)
{
  Serial.print  ("Data Rate:    "); 
  
  switch(accel.getDataRate())
  {
    case ADXL345_DATARATE_3200_HZ:
      Serial.print  ("3200 "); 
      break;
    case ADXL345_DATARATE_1600_HZ:
      Serial.print  ("1600 "); 
      break;
    case ADXL345_DATARATE_800_HZ:
      Serial.print  ("800 "); 
      break;
    case ADXL345_DATARATE_400_HZ:
      Serial.print  ("400 "); 
      break;
    case ADXL345_DATARATE_200_HZ:
      Serial.print  ("200 "); 
      break;
    case ADXL345_DATARATE_100_HZ:
      Serial.print  ("100 "); 
      break;
    case ADXL345_DATARATE_50_HZ:
      Serial.print  ("50 "); 
      break;
    case ADXL345_DATARATE_25_HZ:
      Serial.print  ("25 "); 
      break;
    case ADXL345_DATARATE_12_5_HZ:
      Serial.print  ("12.5 "); 
      break;
    case ADXL345_DATARATE_6_25HZ:
      Serial.print  ("6.25 "); 
      break;
    case ADXL345_DATARATE_3_13_HZ:
      Serial.print  ("3.13 "); 
      break;
    case ADXL345_DATARATE_1_56_HZ:
      Serial.print  ("1.56 "); 
      break;
    case ADXL345_DATARATE_0_78_HZ:
      Serial.print  ("0.78 "); 
      break;
    case ADXL345_DATARATE_0_39_HZ:
      Serial.print  ("0.39 "); 
      break;
    case ADXL345_DATARATE_0_20_HZ:
      Serial.print  ("0.20 "); 
      break;
    case ADXL345_DATARATE_0_10_HZ:
      Serial.print  ("0.10 "); 
      break;
    default:
      Serial.print  ("???? "); 
      break;
  }  
  Serial.println(" Hz");  
}

void displayRange(void)
{
  Serial.print  ("Range:         +/- "); 
  
  switch(accel.getRange())
  {
    case ADXL345_RANGE_16_G:
      Serial.print  ("16 "); 
      break;
    case ADXL345_RANGE_8_G:
      Serial.print  ("8 "); 
      break;
    case ADXL345_RANGE_4_G:
      Serial.print  ("4 "); 
      break;
    case ADXL345_RANGE_2_G:
      Serial.print  ("2 "); 
      break;
    default:
      Serial.print  ("?? "); 
      break;
  }  
  Serial.println(" g");  
}

void setup(void) 
{
  Serial.begin(115200);
  
  Serial.println("Accelerometer Test"); Serial.println("");

   delay(5000);
  
  /* Initialise the sensor */
  if(!accel.begin())
  {
    /* There was a problem detecting the ADXL345 ... check your connections */
    Serial.println("Ooops, no ADXL345 detected ... Check your wiring!");
    while(1);
  }

  WiFi.mode(WIFI_STA);

   delay(5000);

  /* Set the range to whatever is appropriate for your project */
  accel.setRange(ADXL345_RANGE_16_G);
  // accel.setRange(ADXL345_RANGE_8_G);
  // accel.setRange(ADXL345_RANGE_4_G);
  // accel.setRange(ADXL345_RANGE_2_G);
  
  /* Display additional settings (outside the scope of sensor_t) */
  displayDataRate();
  displayRange();
  Serial.println("");
}

void loop(void) 
{
  // Connect or reconnect to WiFi
  if(WiFi.status() != WL_CONNECTED){
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    while(WiFi.status() != WL_CONNECTED){
      WiFi.begin(ssid, pass);  // Connect to WPA/WPA2 network. Change this line if using open or WEP network
      Serial.print(".");
      delay(5000);     
    } 
    Serial.println("\nConnected.");
  }

  
  /* Get a new sensor event */ 
  sensors_event_t event; 
  accel.getEvent(&event);
 
  /* Display the results (acceleration is measured in m/s^2) */
  Serial.print("X: "); Serial.print(event.acceleration.x); Serial.print("  ");
  Serial.print("Y: "); Serial.print(event.acceleration.y); Serial.print("  ");
  Serial.print("Z: "); Serial.print(event.acceleration.z); Serial.print("  ");Serial.println("m/s^2 ");
  delay(500);
}

The circuit connections are as follows -

ESP8266--

• TX - Arduino TX (D1),
• RX - Arduino RX (D0),
• 3.3V - Arduino 3.3V,
• GND - Arduino GND,
• CH_PD - Arduino 3.3V,
• GPIO0 - Arduino GND,
• GPIO2 - No connection,
• RST - No connection

ADXL345 --

• VCC - Arduino 5V,
• GND - Arduino GND,
• SDA - Arduino SDA,
• SCL - Arduino SCL

ARDUINO UNO --

• RESET - Arduino GND

Can someone please, explain to me what I am doing wrong?