ESP32, Sensor

Interface LSM9DS1 9DOF IMU With TTGO T-Display ESP32

by Idris
December 3, 2019

ESP32, LSM9DS1, TTGO

Getting Started With TTGO T-Display ESP32.

Introduction

TTGO T-Display ESP32 is a tiny microcontroller board. It comes with 1.14″ LCD, 2 programmable push button, battery connector with a charging circuit. Since it uses ESP32 module, so it has WiFi and Bluetooth capability. Plus, the price is affordable. Yes, I love it. In this tutorial, I will share how to get started with this board and interface LSM9DS1 9DOF IMU sensor module.

Video

This video shows how to get started with TTGO T-Display ESP32 and interface LSM9DS1 9DOF IMU sensor module.

Hardware Preparation

This is the list of items used in the video.

TTGO T-Display ESP32 1.14 Display Module

LSM9DS1 9DOF Accel/Mag/Gyro/Temp Sensor Module

USB C to Type A Cable (1 Meter)

Jumper Wire

Adjustable 60W Soldering Iron (EU Plug)

Wiring connection table.

TTGO T-Display ESP32	LSM9DS1 9DOF IMU
3.3V	VDD
GND	GND
21	SDA
22	SCL

Sample Program

This is Arduino sample program to read LSM9DS1 data and display to LCD. It requires 2 additional library from Arduino Library Manager:

TFT_eSPI by Bodmer Version 1.4.16.
Adafruit LSM9DS1 Library by Adafruit Version 1.0.1

/*

  Tutorial: Interface LSM9DS1 with TTGO T-Display ESP32

  Board: ESP32 Dev Module (TTGO LCD)

  Ext libraries:

  – TFT_eSPI by Bodmer Version 1.4.16

  – Adafruit LSM9DS1 Library by Adafruit Version 1.0.1

 */

#include <SPI.h>

#include <TFT_eSPI.h>

TFT_eSPI tft = TFT_eSPI(); // Resolution 135 x 240

#define FF17 &FreeSans9pt7b

#define FF21 &FreeSansBold9pt7b

#define ROW1 0,16

#define ROW2 0,38

#define ROW3 0,60

#define ROW4 0,82

#define ROW5 0,104

#define ROW6 0,126

#include <Wire.h>

#include <Adafruit_LSM9DS1.h>

#include <Adafruit_Sensor.h>

Adafruit_LSM9DS1 lsm9ds1 = Adafruit_LSM9DS1();

#define BUTTON1 35

#define BUTTON2 0

long previousMillis = 0;

int interval = 200;

float accX, accY, accZ;

float gyroX, gyroY, gyroZ;

float magnetX, magnetY, magnetZ;

boolean button1Pressed = false;

boolean button2Pressed = false;

int fontColor = 1;

void setup()

{

  pinMode(BUTTON1, INPUT_PULLUP);

  pinMode(BUTTON2, INPUT_PULLUP);

  Serial.begin(115200);

  Serial.println(F("Start"));

  tft.init();

  tft.setRotation(3); // Change 1 or 3 for display orientation

  tft.fillScreen(TFT_BLACK);

  tft.setFreeFont(FF21);

  tft.setTextColor(TFT_RED);

  tft.setCursor(ROW1);

  tft.print("LSM9DS1 Reading");

  tft.setTextColor(TFT_WHITE);

  tft.setCursor(ROW2);

  tft.print("—————————————");

  tft.setTextColor(TFT_BLUE);

  tft.setCursor(ROW3);

  tft.print("A:");

  tft.setCursor(ROW4);

  tft.print("M:");

  tft.setCursor(ROW5);

  tft.print("G:");

  tft.setTextColor(TFT_WHITE);

  tft.setCursor(ROW6);

  tft.print("—————————————");

  tft.setFreeFont(FF17);

  if (!lsm9ds1.begin()) {

    Serial.println(F("Oops… Unable to initialize the LSM9DS1. Check your wiring!"));

    while (1);

  }

  Serial.println(F("Found LSM9DS1 9DOF"));

  lsm9ds1.setupAccel(lsm9ds1.LSM9DS1_ACCELRANGE_2G); // Set the accelerometer range

  lsm9ds1.setupMag(lsm9ds1.LSM9DS1_MAGGAIN_4GAUSS); // Set the magnetometer sensitivity

  lsm9ds1.setupGyro(lsm9ds1.LSM9DS1_GYROSCALE_245DPS); // Setup the gyroscope

}

void loop()

{

  if (millis() – previousMillis > interval) {

    lsm9ds1.read();

    sensors_event_t a, m, g, temp;

    lsm9ds1.getEvent(&a, &m, &g, &temp); 

    accX = a.acceleration.x;

    accY = a.acceleration.y;

    accZ = a.acceleration.z;

    magnetX = m.magnetic.x;

    magnetY = m.magnetic.y;

    magnetZ = m.magnetic.z;

    gyroX = g.gyro.x;

    gyroY = g.gyro.y;

    gyroZ = g.gyro.z;

    Serial.print(F("Accel X: ")); Serial.print(accX); Serial.print(F(" m/s^2"));

    Serial.print(F("\tY: ")); Serial.print(accY); Serial.print(F(" m/s^2"));

    Serial.print(F("\tZ: ")); Serial.print(accZ); Serial.print(F(" m/s^2"));

    Serial.print("Mag X: "); Serial.print(magnetX); Serial.print(F(" gauss"));

    Serial.print("\tY: "); Serial.print(magnetY); Serial.print(F(" gauss"));

    Serial.print("\tZ: "); Serial.print(magnetZ); Serial.println(F(" gauss"));

    Serial.print("Gyro X: "); Serial.print(gyroX); Serial.print(F(" dps"));

    Serial.print("\tY: "); Serial.print(gyroY); Serial.print(F(" dps"));

    Serial.print("\tZ: "); Serial.print(gyroZ); Serial.println(F(" dps"));

    Serial.println();

    tft.fillRect(40, 40, 200, 80, TFT_BLACK);

    if (fontColor == 1) {

      tft.setTextColor(TFT_GREEN);

    }

    else if (fontColor == 2) {

      tft.setTextColor(TFT_YELLOW);

    }

    else if (fontColor == 3) {

      tft.setTextColor(TFT_MAGENTA);

    }

    else if (fontColor == 4) {

      tft.setTextColor(TFT_PURPLE);

    }

    else if (fontColor == 5) {

      tft.setTextColor(TFT_CYAN);

    }

    else if (fontColor == 6) {

      tft.setTextColor(TFT_ORANGE);

    }

    else if (fontColor == 7) {

      tft.setTextColor(TFT_OLIVE);

    }

    tft.setCursor(40, 60);

    tft.print(accX); tft.print("x ");

    tft.print(accY); tft.print("y ");

    tft.print(accZ); tft.print("z");

    tft.setCursor(40, 82);

    tft.print(magnetX); tft.print("x ");

    tft.print(magnetY); tft.print("y ");

    tft.print(magnetZ); tft.print("z");

    tft.setCursor(40, 104);

    tft.print(gyroX); tft.print("x ");

    tft.print(gyroY); tft.print("y ");

    tft.print(gyroZ); tft.print("z");

    previousMillis = millis();

  }

  if (digitalRead(BUTTON1) == LOW &&

      button1Pressed == false) {

    button1Pressed = true;

    fontColor++;

    if (fontColor > 7) {

      fontColor = 1;

    }

  }

  else if (digitalRead(BUTTON1) == HIGH &&

      button1Pressed == true) {

    button1Pressed = false;

  }

  if (digitalRead(BUTTON2) == LOW &&

      button2Pressed == false) {

    button2Pressed = true;

    fontColor–;

    if (fontColor < 1) {

      fontColor = 7;

    }

  }

  else if (digitalRead(BUTTON2) == HIGH &&

      button2Pressed == true) {

    button2Pressed = false;

  }

}