LoRa E32 device for Arduino, esp32 or esp8266: specs and basic usage – Part 1

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LoRa or Long Range wireless data telemetry is a technology pioneered by Semtech that operates at a lower frequency than NRF24L01 (433 MHz, 868 MHz or 916 MHz agains 2.4 GHz for the NRF24L01) but at thrice the distance (from 3000m to 8000m).

LoRa E32-TTL-100

You can find It here

We are going to test E32-TTL-100. It is a wireless transceiver module, operates at 410 441 MHz based on original RFIC SX1278 from SEMTECH, transparent transmission is available, TTL level. The module adopts LORA spread spectrum technology.

The module features FEC Forward Error Correction algorithm, which ensure its high coding efficiency & good correction performance. In the case of sudden interference, it can correct the interfered data packets automatically, so that the reliability and transmission range are improved correspondingly. But without FEC, those da te packets can only be dropped.
And with the rigorous encryption & decryption, data interception becomes pointless. The function of data compression can decrease the transmission time & probability of being interference, while improving the reliability & transmission efficiency.

Operating and transmission type

This device have some interesting function:

Transmission

LoRa E32 transmitting scenarios
Transparent transmission

This can be considered like a “Demo mode”, by default you can send message to all device of same configured address and channel.

Fixed transmission

This type of transmission you can specify an address and a channel where where you want send the message.
You can send message to a:

  • Specified device with a predeterminated Address Low, Address High and Channel.
LoRa E32 Fixed message to a specified device
  • Broadcast a message on predeterminated Channel.
Broadcast message to a set of channel devices

Normal mode

Simply send message.

Wake-up mode and power-saving mode

As you can intend if a device is in Wake-up mode can “wake” one or more devices that are in power-saving mode with a preamble communication.

Program/sleep mode

With this configuration you can change configuration of your device.

Specifications

Here’s the specifications for the module:

  • Module size: 21*36mm
  • Antenna type: SMA-K (50Ω impedance)
  • Transmission distance: 3000m(max)
  • Maximum power: 2dB(100mW)
  • Air rates: 2.4Kbps (6 optional level (0.3, 1.2, 2.4, 4.8, 9.6, 19.2kbps)
  • Emission length: 512Byte
  • Receive length: 512Byte
  • Communication Interface: UART – 8N1, 8E1, 8O1, Eight kinds of UART baud Rate, from 1200 to 115200bps (Default: 9600)
  • RSSI support: No (Built-in intelligent processing)
  • Working frequency: 410MHz-441MHz (Default 433MHz), Channel: 32
Electronic parameter Min. Typ. Max. Unit
Power supply 2.3 3.3 5.5 V
Communication level 3.0 3.3 3.6 V
Transmitting current 102 110 118 mA
Receiving current 121518mA
Sleep current 358 μA
Operating temperature -40 20 +85
Operating humidity 10 60 90 %
Storage temperature -40 20 +125

You must pay attention on communication level that differ from power supply, the second can receive voltage like 3.3v (esp8266 and esp32) and 5v (Arduino), but the first want a 3.3v, so to connecto to an Arduino you must use a Voltage divider (Voltage divider: calculator and application) to prevent damage to the device.

Pinout

E32 TTL 100
Pin No. Pin item Pin direction Pin application
1M0Input(weak pull-up)Work with M1 & decide the four operating modes.Floating is not allowed, can be ground.
2M1Input(weak pull-up)Work with M0 & decide the four operating modes.Floating is not allowed, can be ground.
3RXDInputTTL UART inputs, connects to external (MCU, PC) TXD outputpin. Can be configured as open-drain or pull-up input.
4TXDOutputTTL UART outputs, connects to external RXD (MCU, PC) inputpin. Can be configured as open-drain or push-pull output

5

AUX

Output
To indicate module’s working status & wakes up the external MCU. During the procedure of self-check initialization, the pin outputs low level. Can be configured as open-drain output orpush-pull output (floating is allowed).
6VCC
Power supply 2.3V~5.5V DC
7GND
Ground

As you can see you can set various modes via M0 and M1 pins.

Mode M1 M0 Explanation
Normal00UART and wireless channel is good to go
Wake-Up01Same as normal but a preamble code is added to transmitted data for waking-up the receiver.
Power-Saving10UART is disable and wireless is on WOR(wake on radio) mode which means the device will turn on when there is data to be received. Transmission is not allowed.
Sleep11Used in setting parameters. Transmitting and receiving disabled.

For the next simple test we are going to use Normal mode.

Connecting Wemos D1 mini (esp8266) for a basic usage

esp8266 have the advantage to have same voltage of communication interface so the connection schema is more simple than Arduino.

LoRa E32-TTL-100 Wemos D1 breadboard

It’s important to add pull-up resistor (4,7Kohm) to get good stability.

M0GND (Set normal mode)
M1GND (Set normal mode)
RXPIN D2 (PullUP 4,7KΩ)
TXPIN D3 (PullUP 4,7KΩ)
AUXNot connected
VCC3.3v
GNDGND

Connecting Arduino for a basic usage

Arduino working voltage is 5v, so we need to add a voltage divider on RX pin of LoRa module to prevent damage, you can get more information here Voltage divider: calculator and application.

You can use a 2Kohm resistor to GND and 1Kohm from signal than put together on RX.

LoRa E32-TTL-100 Arduino breadboard
M0GND (Set normal mode)
M1GND (Set normal mode)
RXPIN D2 (PullUP 4,7KΩ & Voltage divider)
TXPIN D3 (PullUP 4,7KΩ)
AUXNot connected
VCC3.3v
GNDGND

Simple communication sketch

If you put to 0 M1 and M0 pin you enter in “Normal” mode, than you can receive and trasmit all the data from device A to B, this modality is defined “Trasparent transmission”.

You can use 2 Arduinos or 2 Wemos D1 mini or one of kind.

At start send a message and if you write on serial from one of device the text is transferred to the other device. You can use 2 Arduinos or 2 Wemos or one and one as you prefer.

Arduino sketch:

/*
 * LoRa E32-TTL-100
 * Start device or reset to send a message
 * https://www.mischianti.org
 *
 * E32-TTL-100----- Arduino UNO
 * M0         ----- GND
 * M1         ----- GND
 * RX         ----- PIN 2 (PullUP & Voltage divider)
 * TX         ----- PIN 3 (PullUP)
 * AUX        ----- Not connected
 * VCC        ----- 3.3v/5v
 * GND        ----- GND
 *
 */
#include "Arduino.h"

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3); // RX, TX

void setup() {
  Serial.begin(9600);
  delay(500);

  Serial.println("Hi, I'm going to send message!");

  mySerial.begin(9600);
  mySerial.println("Hello, world?");
}

void loop() {
  if (mySerial.available()) {
    Serial.write(mySerial.read());
  }
  if (Serial.available()) {
    mySerial.write(Serial.read());
  }
}

Wemos D1 mini sketch:

/*
 * LoRa E32-TTL-100
 * Start device or reset to send a message
 * https://www.mischianti.org
 *
 * E32-TTL-100----- Wemos D1 mini
 * M0         ----- GND
 * M1         ----- GND
 * RX         ----- PIN D2 (PullUP)
 * TX         ----- PIN D3 (PullUP)
 * AUX        ----- Not connected
 * VCC        ----- 3.3v/5v
 * GND        ----- GND
 *
 */
#include "Arduino.h"
#include <SoftwareSerial.h>

SoftwareSerial mySerial(D2, D3); // RX, TX

void setup() {
  Serial.begin(9600);
  delay(500);

  Serial.println("Hi, I'm going to send message!");

  mySerial.begin(9600);
  mySerial.println("Hello, world?");
}

void loop() {
  if (mySerial.available()) {
    Serial.write(mySerial.read());
  }
  if (Serial.available()) {
    mySerial.write(Serial.read());
  }
}

But this basic usage is quite unusefully, so in the next chapter we are going to use my library and go in deep of device features.

Library

Here the last example with my library:

Arduino sketch:

/*
 * LoRa E32-TTL-100
 * Write on serial to transfer a message to other device
 * https://www.mischianti.org
 *
 * E32-TTL-100----- Arduino UNO
 * M0         ----- GND
 * M1         ----- GND
 * RX         ----- PIN 2 (PullUP &amp; Voltage divider)
 * TX         ----- PIN 3 (PullUP)
 * AUX        ----- Not connected
 * VCC        ----- 3.3v/5v
 * GND        ----- GND
 *
 */
#include "Arduino.h"
#include "LoRa_E32.h"

LoRa_E32 e32ttl100(2, 3); // RX, TX

void setup() {
  Serial.begin(9600);
  delay(500);

  Serial.println("Hi, I'm going to send message!");

  // Startup all pins and UART
  e32ttl100.begin();

  // Send message
  ResponseStatus rs = e32ttl100.sendMessage("Hello, world?");
  // Check If there is some problem of succesfully send
  Serial.println(rs.getResponseDescription());
}

void loop() {
	// If something available
  if (e32ttl100.available()>1) {
	  // read the String message
	ResponseContainer rc = e32ttl100.receiveMessage();
	// Is something goes wrong print error
	if (rc.status.code!=1){
		rc.status.getResponseDescription();
	}else{
		// Print the data received
		Serial.println(rc.data);
	}
  }
  if (Serial.available()) {
	  String input = Serial.readString();
	  e32ttl100.sendMessage(input);
  }
}

Here the Wemos D1 (esp8266) sketch:

/*
 * LoRa E32-TTL-100
 * Start device or reset to send a message
 * https://www.mischianti.org
 *
 * E32-TTL-100----- Wemos D1 mini
 * M0         ----- GND
 * M1         ----- GND
 * RX         ----- PIN D2 (PullUP)
 * TX         ----- PIN D3 (PullUP)
 * AUX        ----- Not connected
 * VCC        ----- 3.3v/5v
 * GND        ----- GND
 *
 */
#include "Arduino.h"
#include "LoRa_E32.h"

LoRa_E32 e32ttl100(D2, D3); // RX, TX

void setup() {
  Serial.begin(9600);
  delay(500);

  Serial.println("Hi, I'm going to send message!");

  // Startup all pins and UART
  e32ttl100.begin();

  // Send message
  ResponseStatus rs = e32ttl100.sendMessage("Hello, world?");
  // Check If there is some problem of succesfully send
  Serial.println(rs.getResponseDescription());
}

void loop() {
	// If something available
  if (e32ttl100.available()>1) {
	  // read the String message
	ResponseContainer rc = e32ttl100.receiveMessage();
	// Is something goes wrong print error
	if (rc.status.code!=1){
		rc.status.getResponseDescription();
	}else{
		// Print the data received
		Serial.println(rc.data);
	}
  }
  if (Serial.available()) {
	  String input = Serial.readString();
	  e32ttl100.sendMessage(input);
  }
}

If you have already change configuration you must restore base parameter:

//  If you have ever change configuration you must restore It
	ResponseStructContainer c;
	c = e32ttl100.getConfiguration();
	Configuration configuration = *(Configuration*) c.data;
	Serial.println(c.status.getResponseDescription());
	configuration.CHAN = 0x17;
	configuration.OPTION.fixedTransmission = FT_TRANSPARENT_TRANSMISSION;
	e32ttl100.setConfiguration(configuration, WRITE_CFG_PWR_DWN_SAVE);

but we are going to see It better in the next article.

Thanks

But this kind of usage is very very reductive, in the next articles we are going more in deep, and we start to use massively the library to simplify the complex configuration and settings.

Github library

  1. LoRa E32 device for Arduino, esp32 or esp8266: settings and basic usage
  2. LoRa E32 device for Arduino, esp32 or esp8266: library
  3. LoRa E32 device for Arduino, esp32 or esp8266: configuration
  4. LoRa E32 device for Arduino, esp32 or esp8266: fixed transmission
  5. LoRa E32 device for Arduino, esp32 or esp8266: power saving and sending structured data

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4 Responses

  1. Great library
    Is it possible to get quality parameters such as Signal strength, Signal to noise ratio & frequency error between sender & reciever in E32 module
    These are available in Ai Thinker RA-02 module & help in setting up a reliable network

  2. Llyodie says:

    Hi can i get example of two lora e32 devices to send and receive message? thanks 🙂 great tutorial btw

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