DS-RF Selective Formaldehyde module HCHO Module

Description

Brief Introduction

DS-RF selective formaldehyde module can detect HCHO, VOC, TVOC, t & RH at the  same  time.  The  module  combines  selective  HCHO  sensor  with  advanced electronic control technology, converting HCHO concentration into PPM directly. The module realizes the  detection  of VOC  and  TVOC  based  on  fuel  cell  technology. DS-RF selective HCHO module is free from the influence of the interference gases, such  as  C2H5OH,  C6H6,  NH3,  CO,  etc.  DS-RF  selective  HCHO  module  is pre-calibrated in the factory and can be integrated into your system directly.

Typical Applications      

Smart home

Air purifier

Air conditioners

Portable devices

Wearable devices

HCHO detector

Key Features

Selective detection of HCHO

Detection of HCHO, VOC, TVOC, t, RH together

VOC & TVOC detection based on fuel cell tech.

High precision

Fast response

Long service life

High stability

      

Diagram

 

 

note：1 All dimension is in mm

2 The tolerance is ±0.15mm 

Definition of Pins

PIN	DEFINITION
Pin1	Vin(5V)
Pin2	GND
Pin3	RXD (0～3.3V data input)
Pin4	TXD( 0～3.3V data output)

Technical Specification

MODEL	DS-RF
Detection Principle	Micro fuel cell
Detectable Gas	HCHO	VOC	TVOC
Detection Range	0-1ppm	0-10ppm	0-10ppm
Overload	5ppm	100ppm	100ppm
Resolution	0.001ppm	0.001ppm	0.001ppm
Accuracy	±30ppb or ±10%（25±3℃ &50±5%RH） whichever is greater	/	/
Input Voltage	4.5~7VDC
Response Time (T90)	<120S
Operating temperature range	-40℃~60℃
Operating Humidity Range	10％－90％RH（non-condense）
Lifetime	6years in air
Warranty Period	12 months
Weight	10g

Cross Sensitivity of HCHO

Interference Gas	Concentration of Interference Gas(ppm)	Concentration of HCHO(ppm)
C2H5OH	10	<0.1
C6H6	10	0
CH3COOH	10	0
NH3	10	0
CO	1000	6
H2	1000	6

Communication Protocol

Ø General Settings

Module makes use of serial communication.

Communication configuration parameters are:

Baud rate	9600
Data bits	8 bits
Stop bit	1 bit
Parity bit	None

Ø Communication Command

There are two communication types: active upload type and Q&A type. The default type is active upload and it sends gas concentration once every second. Commands are as follow: 

0

1

2

3

4

5

6

7

8

9

10

11

12

13

start

reserved

C-high

C-low

C-high

C-low

C-high

C-low

±

t-high

t-low

RH-high

RH-low

Checksum

0XFF

0X05

HCHO ppb

HCHO ppb

VOC ppb

VOC ppb

TVOC ppb

TVOC ppb

t +:0/-:1

t ℃

t ℃

RH %

RH %

XX

Gas concentration = C-high*256 + C-low                  1ppm = 1000ppb

temperature = t-high + (t-low / 100 )

humidity = RH-high + (RH-low/ 100)

Switch to Q&A mode：

0	1	2	3	4	5	6	7	8
Start	Reserved	Switch command	Q&A	Reserved	Reserved	Reserved	Reserved	Checksum
0XFF	0X01	0X78	0X41	0X00	0X00	0X00	0X00	0X46

Switch to active upload mode：

0	1	2	3	4	5	6	7	8
Start	Reserved	Switch command	Active upload	Reserved	Reserved	Reserved	Reserved	Checksum
0XFF	0X01	0X78	0X40	0X00	0X00	0X00	0X00	0X47

To read temperature and humidity：

0	1	2	3	4	5	6	7	8
Start	Reserved	Command	Reserved	Reserved	Reserved	Reserved	Reserved	Checksum
0XFF	0X01	0X3F	0X00	0X00	0X00	0X00	0X00	0XC0

To return:

0	1	2	3	4	5	6	7	8
Start	Command	±	t-high	t-low	RH-high	RH-low	Reserved	Checksum
0XFF	0X3F	+:0/-:1	t ℃	t ℃	RH %	RH %	0x00	XX

temperature = t-high + (t-low / 100 )

humidity = RH-high + (RH-low/ 100)

To read gas concentration：

0	1	2	3	4	5	6	7	8
Start	Reserved	Command	Reserved	Reserved	Reserved	Reserved	Reserved	Checksum
0XFF	0X11	0X43	0X00	0X00	0X00	0X00	0X00	0XAC

To return:

0	1	2	3	4	5	6	7	8
Start	Command	C-high	C-low	C-high	C-low	Reserved	Reserved	Checksum
0XFF	0X43	HCHO ppb	HCHO ppb	VOC ppb	VOC ppb	0x00	0x00	XX

Gas concentration = C-high*256 + C-low