# XN04 - Temp-Hum / Lum

XN04 - Temperature - Humidity - Ambient Light

**X-NODE Temp-Hum / Lum** is a module that allows measurement of 3 environmental variables: **Temperature, Humidity and Ambient Light**. Ideal for IoT projects requiring control and monitoring of closed systems, such as air conditioning, refrigeration chambers, or automatic lighting adjustments. This module simplifies designs by reducing the need for multiple devices, offering a compact and efficient solution for monitoring applications. ### TABLE OF CONTENTS 1. [**How does it work?**](#i.-how-does-it-work) 2. [**Hardware description**](#ii.-hardware-description) 3. [**Specifications**](#iii.-specifications) 4. [**Pinout**](#iv.-pinout) 5. [**Usage**](#v.-usage) * [**UARTProtocol**](#uart-protocol) * [**UART Example Arduino Framework**](#uart-example-arduino-framework) * [**I2C Protocol**](#i2c-protocol) * [**I2C Example Arduino Framework**](#i2c-example-arduino-framework) 6. [**Downloads**](#vi.-downloads) * [**Schematic**](https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FbyV2zAlQAiqg46a3Lr8z%2Fuploads%2FcFaznEDQxatEy6prNwMl%2Fschematic.pdf?alt=media\&token=bff01aea-d514-49e9-8d7b-c41ae9a939ef) * [**Dimensions**](https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FbyV2zAlQAiqg46a3Lr8z%2Fuploads%2FEAvXcjTy4yVAr0qRZMzF%2Fdimensions.pdf?alt=media\&token=0d1a1c2b-f723-4763-bdcd-eb254c8511f1) ## I. How does it work? The **X-NODE Temp-Hum / Lum** is a module that combines 2 sensors: a [SHT40](https://sensirion.com/resource/datasheet/sht4x) from [Sensirion®](https://sensirion.com/) for measuring ambient temperature/humidity and an [LTR-329ALS](https://optoelectronics.liteon.com/upload/download/DS86-2014-0006/LTR-329ALS-01_DS_V1.pdf) from [LITEON®](https://www.liteon.com/en) for measuring indoor brightness. It also comes with an integrated controller, that allows you to obtain these variables using a series of *ASCII* commands. **X-NODE Temp-Hum / Lum** is compatible with the [mikroBUS™](https://www.mikroe.com/mikrobus) standard from [Mikroe®](https://www.mikroe.com/) for easy use with a large ecosystem of hardware development kits, and also features JST connectors compatible with the [Qwiic®](https://www.sparkfun.com/qwiic) standard from [SparkFun®](https://www.sparkfun.com/) for quick and easy I2C communication between various modules and development boards. ## II. Hardware description
1. [SHT40](https://sensirion.com/resource/datasheet/sht4x) sensor from [Sensirion®](https://sensirion.com/) 2. JST connectors compatible with [Qwiic®](https://www.sparkfun.com/qwiic) 3. [LTR-329ALS](https://optoelectronics.liteon.com/upload/download/DS86-2014-0006/LTR-329ALS-01_DS_V1.pdf) sensor from [LITEON®](https://www.liteon.com/en) 4. Hardware controller 5. UART <> I2C communication ports 6. X-NODE model 7. X-NODE type 8. [mikroBUS™](https://www.mikroe.com/mikrobus) standard connectors 9. Jumper pad to enable native I2C communication\* with the sensors. 10. Hardware version: R2 11. Main components on the X-NODE {% hint style="info" %} **Note:** The **X-NODE Temp-Hum / Lum** includes a hardware controller to simplify implementation, however, if you wish to use the sensors' native I2C protocol, you must send the command to turn off the hardware controller (see usage) and solder the I2C-EN pads (9). {% endhint %} ## III. Specifications
TypeTemperature, humidity, and ambient light sensor
ApplicationsDevelopment of IoT systems requiring monitoring within closed systems, such as air conditioning, refrigeration chambers, or automatic lighting adjustments.
Module 1SHT40
ManufacturerSensirion®
Module 2LTR-329ALS
ManufacturerLITEON®
Features* Temperature and humidity sensor with detection from 0 °C to 85 °C with typical accuracy of +/- 0.2 °C and +/- 1.8% RH, automatic calibration, 0.5 mA consumption, and high signal-to-noise ratio.
* Ambient light sensor with detection from 0.01 to 64 klx, 50 Hz/60 Hz noise suppression, and typical consumption of 90µA.
InterfaceUART, I2C
CompatibilitymikroBUS™ standard and Qwiic® standard
Size41 x 25.4 x 20.5 mm
Voltage3.3 V
{% hint style="info" %} For complete technical information, you can download each manufacturer's specifications at the following links: [SHT40](https://sensirion.com/resource/datasheet/sht4x) - [LTR-329ALS](https://optoelectronics.liteon.com/upload/download/DS86-2014-0006/LTR-329ALS-01_DS_V1.pdf) {% endhint %} ## IV. Pinout The following table shows the pinout of the **X-NODE Temp-Hum / Lum** with respect to the [mikroBUS™](https://www.mikroe.com/mikrobus) standard (the latter is in the two center columns).
## V. Usage For easy and quick use of the X-NODE, you can use the ASCII command set provided by the integrated hardware controller via UART serial communication, or more advanced use via the I2C protocol. ### UART Protocol **Configuration** UART communication uses the following configuration: * Baud rate: 115,200 bps * Parity: None * Data bits: 8 * Stop bits: 1 **Syntax** The UART protocol allows sending instructions in plain *ASCII* text. Each instruction consists of the X-NODE identifier, a command, and an end-of-line. **Identifier** The **ID** identifier is made up of the X-NODE model, which can be found at point 6 in the Hardware description section, and is complemented by an index, which can be a letter from A to Z, by default is **A**. To connect more than one module of the same model in a system, you must configure a unique identifier for each module, allowing up to 26 modules of the same model to be connected via UART protocol\*.
{% hint style="warning" %} **Note:** From this point on, the default index of the **X-NODE Temp-Hum / Lum** will be used for the rest of the manual: **XN04A**. {% endhint %} **Command list**
XN04A?Checks if communication was established successfully.
Response if successful: OK
Response if error: XN04A=Error
Example: XN04A=3
Error codes:
1: Temperature/humidity sensor error
2: Light sensor error
3: Both sensors errored
XN04A+VGets the current firmware version integrated in the X-NODE.
Response: XN04A=Version
Example: XN04A=2.0.0
XN04A+ID=(A-Z)Changes the ID index to a different uppercase letter from A to Z. Once changed, you must use the new ID to change it again.
Response: OK
Example: XN04C+ID=H
XN04A+TW=(1-126)Changes the factory I2C address to a different one, this only takes effect if the hardware driver is not disabled. The new address is written in decimal, selecting a value from 1 to 126.
Response: OK
Example: XN04A+TW=28
XN04A+GTGets the temperature value from the sensor. Returns the final value in °C with two decimals.
Response: XN04A=VAL
Example: XN04A=27.81
XN04A+GHGets the humidity value from the sensor. Returns a relative humidity (%) value.
Response: XN04A=VAL
Example: XN04A=80
XN04A+GLGets the light value from the sensor. Returns an ambient light value in Lux.
Response: XN04A=VAL
Example: XN04A=198
**Advanced commands**
XN04A+ETW=(0-1)Enables (1) or disables (0) the device's I2C interface.
Note: This setting is volatile, disconnecting power or sending the reset command will restore the I2C interface.
Response: OK
Example: XN04A+ETW=0
XN04A+SLPEnables deep sleep mode to reduce power consumption, during deep sleep, the device will not respond to UART commands. To wake the device, send a logic low (0) to the WAKEUP/UPDI pin.
Response: OK
Example: XN04A+SLP
XN04A+RSTResets the device, non-volatile values (e.g., ID, I2C address) are preserved, and volatile values return to default.
Response: OK
XN04A+SPSets the temperature/humidity sensor precision to high (H)* (default), medium (M), or low (L), lower precision allows faster updates.
Response: OK
Example: XN04A+SP=L
XN04A+SHTurns the humidity sensor heater on (1) or off (0). Use this if humidity readings are incorrect, enable the heater for at least 2 hours to repair the sensor.
Response: OK
Example: XN04A+SH=0
XN04A+SGSets the light sensor gain to 1 (1-64k lux, default), 2 (1-32k lux), 4 (1-16k lux), 8 (1-8k lux), 48 (1-1.3k lux), or 96 (1-600 lux), higher gain means lower range but higher precision.
Response: OK
Example: XN04A+SG=96
XN04A+SDTurns the hardware controller for the sensors on (1) or off (0).
Response: OK
Example: XN04A+SD=1
XN04A+SNReads the serial number of the temperature and humidity sensor.
Response: XN04A=
Example: XN04A=4294900000
When reading temperature, humidity, or light, the following error responses may occur: * **ERROR:** Sensor communication error. * **OL:** Light value overflowed the register, set a lower gain if possible. * **MEASURING:** Sensor reading not finished, wait at least 20 ms for initialization. * **HW\_DRIVER\_OFF:** Hardware controller is not enabled. **End of line** The X-NODE will only respond to a command when a set of end-of-line characters are sent, each command must end with: **\** * CR means carriage return. * LF means line feed. The combination **\** is a common way for computers to represent a new line, e.g., in a word processor to separate paragraphs. For the X-NODE, **\** characters are used to identify the end of a command. If the identifier matches the node, the command exists, and it ends with **\**, the node will send a response. Depending on your system, you must configure sending these characters differently. ### **UART Example Arduino Framework** {% hint style="info" %} Example code for [XC01 - R5](https://docs.microside.com/en/user-manuals/xide/x-nodes/xc01-mcu-wifi-ble/r5/xc01-mcu-wifi-ble-esp32-s3), see the manual to use our [XC01 - R5](https://docs.microside.com/en/user-manuals/xide/xc01-mcu-wifi-ble/r5/xc01-mcu-wifi-ble-esp32-s3#v.-setup-and-usage) in **Arduino IDE/PlatformIO** {% endhint %} ```cpp #include "Arduino.h" float getVariable( const char * command ){ // Clear the buffer if (Serial2.available()) { Serial2.read(); } // Send the command Serial2.print(command); Serial2.println(); // Wait for a response String variable_value = Serial2.readStringUntil('\n'); // If the response starts with the ID, communication was successful if (!variable_value.startsWith("XN04A=")) { Serial.println("Error"); return NAN; } // Convert ASCII value to decimal return variable_value.substring(variable_value.indexOf('=') + 1).toFloat(); } void setup() { // Initialize serial monitor Serial.begin(115200); // Initialize UART communication on MikroBUS port Serial2.begin(115200, SERIAL_8N1, 9, 10); } void loop() { // Get environmental variable values // Send command to get temperature // \r\n represents in C/C++ float temp = getVariable("XN04A+GT\r\n"); // Send command to get humidity float hum = getVariable("XN04A+GH\r\n"); // Send command to get light float lum = getVariable("XN04A+GL\r\n"); Serial.print("Temp: "); Serial.print(temp); Serial.println(" °C"); Serial.print("Hum: "); Serial.print(hum); Serial.println(" %"); Serial.print("Lum: "); Serial.print(lum); Serial.println(" lx"); delay(1000); } ``` ### I2C Protocol To establish communication, you must know the I2C address of the X-NODE, the factory value is 0x04. I2C addresses are usually represented in **hexadecimal**, make sure to use the correct number system. **Configuration** * Communication speed: 100 kHz - 400 kHz * Address: 7 bits {% hint style="info" %} **Note:** Make sure you do not have another device with the same address on the I2C BUS, if so, remember that the X-NODE can change its I2C address with the **XN04A+TW=(1-126)** command. {% endhint %} **Write** To write to a register of the **X-NODE Temp-Hum / Lum**, the I2C controller must perform the following operations: 1. Send a **start condition**: The controller generates a logic low (0) on SDA while SCL remains high (1). 2. Send the **X-NODE address**: The controller sends the 7-bit address. 3. Send the **operation type**: The controller indicates if the operation is read (0) or write (1). 4. Wait for an **acknowledge (ACK)**: The controller waits for a logic low (0) as confirmation (Acknowledgment) that a target with the sent address exists on the I2C BUS. If no response (1), there was a communication error or the address is incorrect. 5. Write **n bytes** of data: The controller writes n bytes in 8 bit (1 byte) sequences, MSB first. The target will send an **ACK** for each byte written. 6. Send a **stop condition**: The controller releases the I2C BUS by generating a logic high (1) on SDA while SCL is high (1). **Read** To read from a register of the **X-NODE Temp-Hum / Lum**, the I2C controller must perform the following operations: 1. Send a **start condition**: The controller generates a logic low (0) on SDA while SCL remains high (1). 2. Send the **X-NODE address**: The controller sends the 7 bit address. 3. Send the **operation type**: The controller indicates if the operation is read (0) or write (1). 4. Wait for an **acknowledge (ACK)**: The controller waits for a logic low (0) as confirmation (Acknowledgment) that a target with the sent address exists on the I2C BUS. If no response (1), there was a communication error or the address is incorrect. 5. Read **n bytes** of data: The target will send n bytes in 8 bit (1 byte) sequences, MSB first, after receiving a byte, the controller must send an **ACK** to request another byte, or a **NACK** to indicate the end of transmission and request the target to release the BUS. 6. Send a **stop condition**: The controller releases the I2C BUS by generating a logic high (1) on SDA while SCL is high (1). **Register list** In an I2C target, registers are memory addresses that allow configuring or obtaining data from the target. There are two types of operations: read (R) and write (W).
RegisterAddress (hex)TypeNo. BytesDescription
TEMP0x01R2Gets the temperature value in °C*100, divide by 100 to get °C
HUM0x02R2Gets the relative humidity value * 100, divide by 100 to get percentage (0-100%)
LUM0x03R2Gets the ambient light (ALS) value in Lux
HEATER0x04R/W1Turns the humidity sensor heater on (1) or off (0). Use this if humidity readings are incorrect, enable the heater for at least 2 hours to repair the sensor.
PRECISION0x05R/W - NV1Sets the temperature/humidity sensor precision to high (3)* (default), medium (2), or low (1), lower precision allows faster data updates.
GAIN0x06R/W - NV1Sets the light sensor gain to 1 (1-64k lux, default), 2 (1-32k lux), 4 (1-16k lux), 8 (1-8k lux), 48 (1-1.3k lux), or 96 (1-600 lux). Higher gain means lower range but higher precision.
SERIAL_NUM0x07R4Reads the serial number of the temperature and humidity sensor
DRIVER0x36R/W - NV1Turns the hardware controller for the sensors on (1) or off (0)
STAT0x37R1XNODE status, 0x00 if no errors, any other value means communication error.
Error codes:
1: Temperature/humidity sensor error
2: Light sensor error
3: Both sensors errored
FW0x38R3Firmware version, in major, minor, and patch: 0x02.0x00.0x00
UART_ID0x39R/W - NV1Reads and writes the ID index as a letter from A (0x41) to Z (0x5A)
TW_ADD0x3AR/W - NV1Reads and writes the device's I2C address from 1 (0x01) to 126 (0x7D). Requires a reset or a power-on sequence to be applied
UART_EN0x3BW1Enables (0x01) or disables (0x00) the device's UART interface
SLEEP0x3CW1Enables (0x01) or disables (0x00) deep sleep, the device will wake up if the master writes the device's I2C address on the BUS
RESET0x3DW1Writing 0x01 resets the device
WHO_AM_I0x3ER2First byte is the XNODE model, second byte is the hardware revision
**Non-volatile registers (NV)** Non-volatile registers are stored in the device's EEPROM, meaning they retain their values even if the device is powered off. **TEMP, HUM, LUM register structure:** When reading temperature, humidity, or light, the following reserved values indicate errors: * **0xFFFF:** Sensor communication error. * **0xFFFE:** Light value overflowed the register, set a lower gain if possible. * **0xFFFD:** Sensor reading not finished, wait at least 20 ms for initialization. * **0xFFFC:** Hardware controller is not enabled.
### **I2C Example Arduino Framework** {% hint style="info" %} Example code for [XC01 - R5](https://docs.microside.com/en/user-manuals/xide/x-nodes/xc01-mcu-wifi-ble/r5/xc01-mcu-wifi-ble-esp32-s3), see the manual to use our [XC01 - R5](https://docs.microside.com/en/user-manuals/xide/xc01-mcu-wifi-ble/r5/xc01-mcu-wifi-ble-esp32-s3#v.-setup-and-usage) in **Arduino IDE/PlatformIO** {% endhint %} ```cpp #include #include void setup() { // Initialize serial monitor Serial.begin(115200); // Set I2C communication pins Wire.setPins( 12, 13 ); // Initialize I2C communication Wire.begin(); } void loop() { // Get environmental variable values float temperature; float humidity; int lum; Wire.beginTransmission(0x04); Wire.write(0x01); if ( Wire.endTransmission() != 0) { delay(1000); return; } if (Wire.requestFrom(0x04, 2) != 2) { delay(1000); return; } // Divide by 100 to get value in Celsius temperature = ( (Wire.read() << 8) | Wire.read() )/100.0f; Wire.beginTransmission(0x04); Wire.write(0x02); if ( Wire.endTransmission() != 0) { delay(1000); return; } if (Wire.requestFrom(0x04, 2) != 2) { delay(1000); return; } // Divide by 100 to get value in percent relative humidity humidity = ( (Wire.read() << 8) | Wire.read() )/100.0f; Wire.beginTransmission(0x04); Wire.write(0x03); if ( Wire.endTransmission() != 0) { delay(1000); return; } if (Wire.requestFrom(0x04, 2) != 2) { delay(1000); return; } lum = ((Wire.read() << 8) | Wire.read()); Serial.print("Temperature:"); Serial.print(temperature); Serial.println(" C"); Serial.print("Humidity:"); Serial.print(humidity); Serial.println(" %"); Serial.print("Light: "); Serial.print(lum); Serial.println(" lx"); delay(1000); } ``` ## VI. Downloads
Schematichttps://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FbyV2zAlQAiqg46a3Lr8z%2Fuploads%2FcFaznEDQxatEy6prNwMl%2Fschematic.pdf?alt=media&token=bff01aea-d514-49e9-8d7b-c41ae9a939ef
Dimensionshttps://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FbyV2zAlQAiqg46a3Lr8z%2Fuploads%2FEAvXcjTy4yVAr0qRZMzF%2Fdimensions.pdf?alt=media&token=0d1a1c2b-f723-4763-bdcd-eb254c8511f1