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UNICHIPS DUST S ensors Product Data Sheet

Doc. No. : DOC_EN01-DS1705A Page 1 of 12

Part Name DUST Sensor Part No. DS1705A Rev. 0.1

SPECIFICATION

Product Name: Dust Sensor DS1705A

Review Check Approve

Technology

Quality

Supplier



UNICHIPS Co., LTd.

Table of Contents

1. Description ............................................................................................................................................................ 3

2. Feature ................................................................................................................................................................... 3

3. Application ............................................................................................................................................................ 4

4. Schematic .............................................................................................................................................................. 4

5. Protocol .............................................................................................................................................................. 4

6. Electrical Characteristic ........................................................................................................................................ 6

7. Connector .............................................................................................................................................................. 7

8. Pin Configuration .................................................................................................................................................. 8

9. Electro - Optical Characteristics ........................................................................................................................... 9

10. Dust Signal Pulse ................................................................................................................................................ 9

11. Note for application .......................................................................................................................................... 10

12. Test Standard for dust sensor calibration .......................................................................................................... 13

13. Reliability .......................................................................................................................................................... 13

14. Packing specification ........................................................................................................................................ 13

15. Outline Dimension ............................................................................................................................................ 14

16. Document Revision History .............................................................................................................................. 14



UNICHIPS Co., LTd.

DS1705A

Dust sensor for air purifier

1. Description

DS1705A is a dust sensor that detects the dust particle concentration in air by using optical

sensing method. An infrared light emitting diode (IR LED) and a photo-sensor are optically

arranged in this device. The photo-sensor detects the reflected IR LED light by dust particles in air.

This dust sensor can detect the small particle like cigarette smoke and it can distinguish small

particles like smoke from large house dust by pulse pattern of signal output. This sensor has the

interface of PWM, UART.

2. Features

Compact size, light weight about 58.5(W) x 46(D) x 18(T) mm, ~23g.

UART output and PWM (pulse width modulation) output

Heart beat to monitor dust sensor life time and wire connection

Number display P.M 2.5

Constant air flow by heater resister in dust sensor.

Lead free and ROHS

Minimum particle size can be detected over 1㎛

(House dust size: avg. 20㎛, yellow dust size: avg. 20㎛, cigarette dust size: avg. 1㎛)



UNICHIPS Co., LTd.

3. Application

Detection of dust in the air, Indoor Air quality monitoring.

Air cleaner, Air purifier, Air conditioner.

Display P.M2.5, P.M10 particles by optical particle countering method.

Number Display of dust concentration

4. Schematic

5. Protocol(PWM mode)

5.1 PWM mode: normal mode.

- P1(Pin4) : PWM output for small particle(Average 1um)

20 second moving averaged pulse width by MICOM program to stabilize dust signal data

Single Low Pulse Output value at one second interval.

<Example>

LPO(5%) = Single pulse out of 50mSec pulse width at 1000mS interval

DS1705A MICOM

P1

P2

VCC

GND



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6. Electrical Characteristic

6.1 Absolute Maximum Ratings

Parameter Symbol Rating Unit

Supply voltage V cc -0.3 to + 7.0 V

Operating temperature T opr -10 to 60 ℃

Storage temperature T stg -30 to 80 ℃

6.2 Operating Supply Voltage and Signal Output

(Ta=25 ℃)

Parameter Symbol Rating Unit

Supply voltage V cc DC 5 ± 5%, Ripple <50mV at 60HZ*3 V

Current Consumption I cc < 100± 10% mA

Signal

output

PWM P1,P2

(PWM)

Hi : > 4.5V, Lo : <0.7V, *1

Negative Logic Pulse output Negative

Low pulse

UART

Baud rate 9600 bps

Data bit 8 Bits

Parity bit No Bit

Stop bit 1 Bit

Warm up time 100 Sec

6.3 Recommend Operating Temperature/Humidity

Parameter Rating Unit

Operating

Temp./Humidity -10℃ ~ 45℃, < 85%RH *1 ℃, %RH

*1. Dust sensor can detect the micro size water droplet, like fog and mist, as particles.

Please do not use the dust sensor in fog place, hot bath place or near humidifier.

But the de-solved water droplet in the high humid air is under submicron size and the dust sensor

cannot detect this submicron size water droplet.

7. Connector

Standard connector(DS1705A) Connector Part No. Symbol Description Maker

Connector SMAW250-05G 2.5mm pitch YeonHo Elec.(Korea)

http://www.yeonho.com/

Housing 25048HS-05

Terminal YST025

- SMAW250-05G is standard type connector.



UNICHIPS Co., LTd.

8. Connector Pin Configuration

Number Symbol Pin Description

Pin 1 GND Ground, Connect with System ground

Pin 2 P2 Low pulse Signal output(P2) of large particle, active low PWM

TXD TBD

Pin 3 Vcc Input Supply voltage (+5 V)

Pin 4 P1 Low pulse Signal output(P1) of small particle, active low PWM

Pin 5 NC no connected,

RXD TBD

- Please refer the drawing for pin number assignment.

- For P1 and P2, Do not need to external pull up resister, internal pull up resistor is 10K.

9. Electro-Optical Characteristics



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10. Dust Signal pulse

10.1 Single Low pulse width vs LPO(%) relationship

Parameter Symbol Conditions Min Typ Max Unit

Single Low pulse

width of a small

particle (P1) Tsp

*1

Cigarette smoke 1 LPO(%)/100*1000 mSec

Single Low pulse

width of a large

particle(P2) Tlp

*2

House dust 1 LPO(%)/100*1000 mSec

*1. Single low pulse width during 1000mS period is decided by LPO concentration.

In not heavily contaminated condition, 100,000 particle/ft3 of cigarette smoke, output pulse width of

P1 pin is the average detection result of average one micrometer size of particles based on cigarette

smoke during one second using eight second moving average.

The pulse width is calculated as follows:

- Typical LPO value of 100,000 particle/ft3 is 2% from Fig.1 data sheet.

- Output pulse width (mSec) = 2/100*1000(mSec) = 20mSec at 1000mSec interval.

*2. Low pulse width of a house dust is longer than cigarette smoke particle.

P2 can be used to detect large particle like house dust and pollen.



UNICHIPS Co., LTd.

11. Notes for application

11.1 EMI and Power line noise protection and malfunction

To protect EMI affection of photo sensor signal from motor and high voltage source, another

bottom metal shield case could be soldered on electronic PCB’s ground by customer requirements.

Normally, top shield case is enough to protect EMI from outer electronic goods. However, to

prevent EMI from high voltage negative ion generator and power line noise from electric dust

collector, please install the high voltage generator in the opposite side from dust sensor also pay

attention to prevent power line noise by using noise filter. The malfunction of dust senor can be

observed by taping all holes of dust sensor completely not to penetrate dust into open holes of dust

senor. After making clean the dust sensor chamber and taping all holes not to come any dusts into

optical zone of sensor and operate the sensor. In this experiment dust sensor has not to show any

low pulse output. If it is interrupted by EMI and line noise, many Low pulse output signal will be

showed up. In this case, please consult to UNICHIPS’s technical team.

11.2 Dust Sensor install Method

When customer install the dust sensor in air cleaner, dust sensor must be installed vertically in the

place that is not affected by air flow caused by motor fan rotation. We recommend to install dust

sensor in the front panel side. The dust sensor can detect the water vapor as dust. Please do not use

dust sensor in vaporizing place like bathroom or at near air humidifier. Dust sensor use IR

wavelength LED and the visible cutoff photo sensor, but the irradiation by lamp light of optical

sensing zone will cause malfunction of dust sensor. Please protect the center hole shaped triangle

for dust sensor optics not to irradiate directly. Please do not close the bottom and top hole for air

flow to measure the dust. The center hole of PCB is for screwing bolt to system. Please use screw

PH 3 pie for fixing. Please pay attention not to damage the sensor optics and cover case. The

heater resister is installed inside of dust sensor for inducing the forced air convection and the

heated air flows from bottom side to top side direction. The heater resister’s temperature is

increased over 40℃ than atmosphere. So, vertical positioning of dust sensor is important for air

flow direction and speed optical zone. The air flow direction and flow speed can affect the signal

output of dust sensor. Please keep ± 5 degree position vertically.

11.3 Cleaning

Cigarette tar on the lens should affect the sensitivity of dust senor. Wet swab with alcohol and rub

softly the lens and dry. Normally wet cleaning is not recommended, because there is a case this

device is not satisfied with its characteristics by wet cleaning. If large particle such as home dust

are accumulate in the dust sensor optics parts, please consider the maintenance such as vacuuming

or blowing off the dust by air.

11.4 Sensitivity adjustment, customized low pulse output data control by MICOM

programming

Dust sensor sensitivity is adjusted by MICOM program. Customer cannot change the sensitivity by

volume resister. MICOM send the low pulse output data proportional with dust concentration.

Also MICOM can be programmed to send the communication code with system MICOM like code

for LED level or code for monitoring sensor life. If customer wants to use dust sensor to special



UNICHIPS Co., LTd.

purpose like fire detection, MICOM program can be changed to send low pulse data for fire alarm

level warning. Please contact to UNICHIPS technical team for more information.

11.5 Responsibility

This product shall not contain the following materials banned in RoHS Directive. (2002/95/EC)

- Pb, Hg, Cd, Cr+6, PBB, PBDE

UNICHIPS takes no responsibility for any problems related to any intellectual property right of a

third party resulting from the use of UNICHIPS ’s device. UNICHIPS takes no responsibility for

damage caused by improper use of the device which does not meet the condition of absolute

maximum ratings to be specified in relevant specification sheet nor meet the condition of the

extremely high level of reliability and safety such as safety device, clean room monitoring, fire

alarm, life support equipment, etc.

This publication is the proprietary product of UNICHIPS and is copyright with all rights reserved.

Under the copyright laws, no part of this publication may be reproduced or transmitted in any form

of or by any means, for any purpose, without the express written permission of UNICHIPS. The

express written permission is also needed before any use of this publication by a third party.

Please contact with an UNICHIPS representative if there are any questions for this publication.

12. Test Standard for dust sensor calibration

The first standard is the certificated particle counter. (Metone, HACC)

The second standard is the master dust sensor and the master dust sensor is always used for the

process quality control of production.

This master dust sensor will be compared with the customer master sensor once every six month.

All dust sensor is calibrated by MICOM auto calibration program of dust sensor.



UNICHIPS Co., LTd.

13. Reliability

1 Drop Drop it unintentionally from 100cm height down to the hard wooden board

three times at random direction

- No damage,

- No breakage,

- Output

Within ±30% of

the initial LPO of

sample)

N=10

2 High temp.

Storage Leave in the atmosphere 80℃ for 1,000 hours

3 Low temp.

storage

Leave in the atmosphere -30℃ for 1,000 hour

4 Thermal Cycle

Repeat 20 times in the following cycle.

5 Thermal

Shock

Repeat 20 times in the following cycle.

6 High Temp.

Operation Operating it in the atmosphere of 60℃ for 1000 hours

7 Low Temp.

Operation Operating it in the atmosphere of -10℃ for 1000 hours

8 Mechanical

shock

Frequency : 5~55~5Hz

Acceleration : 21.6m/s^2(2.2G)

Direction : X,Y,Z direction for 2 hours

N=2



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14. Packaging Specification

TBD

15. Outline Dimension



UNICHIPS Co., LTd.

16. Document Revision History

No. Section and description of revision: Date Author

0.1 Initial released

Date post:	11-Sep-2018
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