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;
	}
	}