RS485 Waterproof Ambient Light Sensor (0-200,000 Lux) แท้จาก DFRobot

Introduction

The Waterproof Digital Ambient Light Sensor is a robust and versatile device designed to measure light intensity across a wide range of environments, from 0 to 200,000 Lux. Utilizing the Modbus-RTU 485 communication protocol and powered by a DC 5-32V wide voltage supply, it ensures seamless integration with systems like the Arduino via compatible expansion boards.

With an IP68 waterproof rating, the sensor can withstand complete submersion, making it ideal for both indoor and outdoor applications, including weather stations, greenhouses, outdoor lighting, and automotive smart lights. Its high accuracy (±5%), broad measurement range, and durable construction make it a reliable solution for demanding environments.

IP68 Waterproof Design

The sensor is fully waterproof, meeting the IP68 standard, and can be submerged in water without damage. This makes it suitable for use in harsh outdoor environments, such as weather stations, greenhouses, and automotive applications, ensuring consistent performance in wet or humid conditions.

Wide Range and High Accuracy

With a measurement range of 0-200,000 Lux and a resolution of 0.01 Lux, the sensor provides precise light intensity readings across diverse scenarios, from dim indoor settings to bright outdoor environments. Its ±5% accuracy ensures reliable data for critical applications like plant growth monitoring and lighting control.

Easy Integration and Compatibility

The sensor supports the Modbus-RTU 485 protocol and can be easily connected to Arduino and other microcontroller platforms using expansion boards like the TTL to RS485 module or the Gravity: Active Isolated RS485 to UART Signal Adapter. Its simple wiring and wide voltage power supply (DC 5-32V) make it user-friendly and adaptable to various setups.

Applications

• Weather Stations: Monitor ambient light for accurate weather data collection.
• Greenhouses: Optimize plant growth by measuring light intensity in vegetable and flower cultivation.
• Outdoor Lighting: Automate streetlights or garden lighting based on ambient light levels.
• Automotive Smart Lights: Enhance vehicle safety with adaptive lighting systems.
• Factory Lighting: Ensure optimal lighting conditions in industrial workshops.

Specification

• Power supply voltage: DC 5-32V
• Working current: <10mA
• Output mode: RS485
• Measurement range: 0-200,000 Lux
• Resolution: 0.01 Lux
• Accuracy: ±5%
• Working temperature: -40°C~+80°C
• Protection level: IP68
• Thread length: 10mm
• Opening size: 25mm
• Wrench size: 33mm
• Cable diameter: 4-10mm
• Line length: 1m

Documents

• Product wiki
• Dimensional Drawing
• Communication Protocol
• Tutorial
• FAQ

Shipping List

• RS485 Waterproof Ambient Light Sensor (0-200,000 Lux) x1

Board Overview

Dimensional Drawing

Communication Protocol

1. Basic communication parameters

2. Data frame format definition

Using Modbus-RTU communication protocol, the format is as follows:

Initial structure ≥4 bytes of time

Address code = 1 byte

Function code = 1 byte

Data area = N bytes

Error check = 16-bit CRC code

End structure ≥4 bytes of time

Address code: The address of the sensor, which is unique in the communication network (factory default 0x01).

Function code: The function indication of the command sent by the host. This sensor reads the register function code 0x03 and writes the register function code 0x06

Data area: The data area is the specific communication data. Note that the high byte of 16-bit data is in front!

CRC code: A two-byte check code.

Register address

3. Communication protocol example and explanation

3.1、Read multiple register illumination data instruction

Inquiry frame:

Response frame:

Light value:

00 0C F4 73 (hexadecimal) =849011/1000 =>Light value = 849.011Lux

3.2, Modify the current address

Inquiry frame: (Modify the current address to 0x02)

Response frame:

3.3, Modify address, baud rate

Inquiry frame: (Modify address to 0x01, baud rate to 9600)

After modifying the address or baud rate, the sensor needs to be powered off and reconnected

Response frame:

3.4, query current address, baud rate

Inquiry frame:

Response frame:

The real address of the device read is 01, and the baud rate is 0x03, which is 9600.

3.5, Device factory reset command

Inquiry frame:

Response frame:

Tutorial

Requirements

• Hardware
  • DFRduino UNO R3 (or similar) x 1
  • Gravity: Active Isolated RS485 to UART Signal Adapter Module x1
  • RS485 Waterproof Ambient Light Sensor(0-200klux) x1

• Software
  • Arduino IDE

Connection Diagram

If the power of the RS485 device is small and the required current is less than 12V-160mA, the RS485 to UART signal conversion module does not require a 12V external power supply, making wiring more convenient.

Sample Code

#include <SoftwareSerial.h>
SoftwareSerial mySerial(2,3);
uint8_t Com[8] = { 0x01, 0x03, 0x00, 0x02, 0x00, 0x02, 0x65, 0xCB };
float LUX;
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
}
void loop() {
readLux();
Serial.print("Lux = ");
Serial.print(LUX, 3);
Serial.println(" (lux) ");
delay(1000);
}
void readLux(void) {
uint8_t Data[10] = { 0 };
uint8_t ch = 0;
bool flag = 1;
while (flag) {
delay(100);
mySerial.write(Com, 8);
delay(10);
if (readN(&ch, 1) == 1) {
if (ch == 0x01) {
Data[0] = ch;
if (readN(&ch, 1) == 1) {
if (ch == 0x03) {
Data[1] = ch;
if (readN(&ch, 1) == 1) {
if (ch == 0x04) {
Data[2] = ch;
if (readN(&Data[3], 6) == 6) {
if (CRC16_2(Data, 7) == (Data[7] * 256 + Data[8])) {
LUX = (Data[3] * 0x1000000 + Data[4] * 0x10000 + Data[5] * 0x100 + Data[6]) / 1000.000;
flag = 0;
}
}
}
}
}
}
}
}
mySerial.flush();
}
}

uint8_t readN(uint8_t *buf, size_t len) {
size_t offset = 0, left = len;
int16_t Tineout = 500;
uint8_t *buffer = buf;
long curr = millis();
while (left) {
if (mySerial.available()) {
buffer[offset] = mySerial.read();
offset++;
left--;
}
if (millis() - curr > Tineout) {
break;
}
}
return offset;
}

unsigned int CRC16_2(unsigned char *buf, int len) {
unsigned int crc = 0xFFFF;
for (int pos = 0; pos < len; pos++) {
crc ^= (unsigned int)buf[pos];
for (int i = 8; i != 0; i--) {
if ((crc & 0x0001) != 0) {
crc >>= 1;
crc ^= 0xA001;
} else {
crc >>= 1;
}
}
}

crc = ((crc & 0x00ff) << 8) | ((crc & 0xff00) >> 8);
return crc;
}

Expected Results

Print the collected light values

FAQ

Possible reasons for no output or output errors:

1. The sensor is a precision device. Please do not disassemble it by yourself when using it to avoid damage to the product.
2. If the reading value is 0, check whether there is a light source and whether the product protective cover is removed.
3. The 485 bus is disconnected, or the A and B lines are connected in reverse.
4. Check whether the power supply meets the marking.