AM2303 Datasheet by Adafruit Industries LLC

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Digital-output
Digital-output
Digital-output
Digital-output relative
relative
relative
relative humidity
humidity
humidity
humidity &
&
&
& temperature
temperature
temperature
temperature sensor/module
sensor/module
sensor/module
sensor/module
AM2303
AM2303
AM2303
AM2303
Capacitive -type humidity and temperature module/sensor
1.
1.
1.
1.
Feature
Feature
Feature
Feature &
&
&
& Application
Application
Application
Application :
:
:
:
* Full range temperature compensated * Relative humidity and temperature measurement
* C alibrated digital signal *O utstanding long-term stability *E xtra components not needed
* L ong transmission distance * L ow power consumption *4 pins packaged and fully interchangeable
2.
2.
2.
2.
Description:
Description:
Description:
Description:
AM2303 output calibrated digital signal. It utilizes exclusive digital-signal-collecting-technique and humidity
sensing technology, assuring its reliability and stability.Its sensing elements is connected with 8-bit single-chip
computer.
Every sensor of this model is temperature compensated and calibrated in accurate calibration chamber and the
calibration-coefficient is saved in type of programme in OTP memory, when the sensor is detecting, it will cite
coefficient from memory.
Small size & low consumption & long transmission distance(20m) enable AM2303 to be suited in all kinds of
harsh application occasions.
Single-row packaged with four pins, making the connection very convenient.
3. Technical
Technical
Technical
Technical Specification:
Specification:
Specification:
Specification:
Model
AM2303
Power supply
3.3- 6 V DC
Output signal
digital signal via single-bus
Sensing element
Polymer humidity capacitor & DS18B20 for detecting temperature
Measuring range
humidity 0-100%RH ; temperature -40~ 125 Celsius
thomasliul98518@ ahoo.com.cn salcs@aosong.com Address: No.56 chhc Road chhc Town Bai nDistrict Guan on China @3‘OR7L.© ace ’ C 1 mm 20.029 equence number: 1
Aosong(Guangzhou) Electronics Co.,Ltd---------------------------------------------------------------------------------------------------------------------
Tell: +86-020-36380552, +86-020-36042809 Fax: +86-020-36380562
http://www.aosong.com
Email: thomasliu198518@yahoo.com.cn sales@aosong.com
Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
- 2 -
4.
4.
4.
4. Dimensions:
Dimensions:
Dimensions:
Dimensions: (unit----mm)
(unit----mm)
(unit----mm)
(unit----mm)
Pin
Pin
Pin
Pin sequence
sequence
sequence
sequence number:
number:
number:
number: 1
1
1
1 2
2
2
2 3
3
3
3 4
4
4
4 (from
(from
(from
(from left
left
left
left to
to
to
to right
right
right
right direction).
direction).
direction).
direction).
5.
5.
5.
5. Operating
Operating
Operating
Operating specifications:
specifications:
specifications:
specifications:
(1)
(1)
(1)
(1) Power
Power
Power
Power and
and
and
and Pins
Pins
Pins
Pins
Power's voltage should be 3 .3 - 6 V DC . When power is supplied to sensor, don't send any instruction to the sensor
within one second to pass unstable status. One capacitor valued 100nF can be added between VDD and GND for
wave filtering.
(2)
(2)
(2)
(2) Communication
Communication
Communication
Communication and
and
and
and signal
signal
signal
signal
Single-bus data is used for communication between MCU and AM2303, it costs 5mS for single time
communication.
Accuracy
humidity +- 2 %RH(Max +-5%RH) ; temperature + -0.2 Celsius
Resolution or sensitivity
humidity 0.1%RH ; temperature 0.1Celsius
Repeatability
humidity +-1%RH ; temperature +-0.2Celsius
Humidity hysteresis
+-0.3%RH
Long-term Stability
+-0.5%RH/year
Sensing period
Average: 2 s
Interchangeability
fully interchangeable
Pin
Pin
Pin
Pin
Function
Function
Function
Function
1
1
1
1
VDD----power
VDD----power
VDD----power
VDD----power supply
supply
supply
supply
2
2
2
2
DATA--signal
DATA--signal
DATA--signal
DATA--signal
3
3
3
3
NULL
NULL
NULL
NULL
4
4
4
4
GND
GND
GND
GND
thomasliul98518@ ahoo.com.cn salcs@aosong.com Address: No.56 Renhe Road Renhe Town Baivun District Guangzhou China T 4‘ Hum ‘b—d 1mm :— —-¢ mm ‘L ma VCC’ rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr GND 77777777777777777777777777777777777777777 \ Him: \ ‘fififilfi‘ \ Mums Wi \ 4;; fig 4mm: 1- --1 3m U = fi%fififli — - i %% D '3 $ i d wait Host's 5 bit "1 " Sensor p
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Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
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Data is comprised of integral and decimal part, the following is the formula for data.
AM2303 send out higher data bit firstly!
DATA=8 bit integral RH data+8 bit decimal RH data+8 bit integral T data+8 bit decimal T data+8 bit check-
sum
If the data transmission is right, check-sum should be the last 8 bit of "8 bit integral RH data+8 bit decimal RH
data+8 bit integral T data+8 bit decimal T data".
When MCU send start signal, AM2303 change from low-power-consumption-mode to running-mode. When
MCU finishs sending the start signal, AM2303 will send response signal of 40-bit data that reflect the relative
humidity and temperature information to MCU. Wi thout start signal from MCU, AM2303 will not give response
signal to MCU. One start signal for one time's response data that reflect the relative humidity and temperature
information from AM2303. AM2303 will change to low-power-consumption-mode when data collecting finish if
it don't receive start signal from MCU again.
1) Check bellow picture for overall communication process:
------------------------------------------------------------------------------------------------------------------------------------
Host computer send out
start signal. Data transmission finished,
Sensor send out and RL pull up bus's voltage
response signal. Output data: 1bit"0" for next transmission
Pull up and wait Host's signal Sensor's signal Output data: 1bit "1"
response from sensor Sensor pull down
Pull up voltage and get bus's voltage
ready for sensor's output.
Single-bus output
------------------------------------------------------------------------------------------------------------------------------------
thomasliul98518@ ahoo.com.cn salcs@aosong.com Address: No.56 Renhe Road Renhe Town Baivun District Guangzhou China from sen
Aosong(Guangzhou) Electronics Co.,Ltd---------------------------------------------------------------------------------------------------------------------
Tell: +86-020-36380552, +86-020-36042809 Fax: +86-020-36380562
http://www.aosong.com
Email: thomasliu198518@yahoo.com.cn sales@aosong.com
Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
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2) Step 1: MCU send out start signal to AM2303
Data-bus's free status is high voltage level. When communication between MCU and AM2303 begin, program
of MCU will transform data-bus's voltage level from high to low level and this process must beyond at least 18ms
to ensure AM2303 could detect MCU's s ignal, then MCU will wait 20-40us for AM2303's response.
Check bellow picture for step 1:
------------------------------------------------------------------------------------------------------------------------------------
Host computer send start signal Sensor send out response signal
- and keep this signal at least 500us
500us
500us
500us - and keep this signal 80us
Host pull up voltage
-and wait sensor's response Sesnor pull up bus's voltage
Signal from host Start data transmission
Signal from sensor
Single-bus signal
------------------------------------------------------------------------------------------------------------------------------------
Step 2: AM2303 send response signal to MCU
When AM2303 detect the start signal, AM2303 will send out low-voltage-level signal and this signal last 80us
as response signal, then program of AM2303 transform data-bus's voltage level from low to high level and last
80us for AM2303's preparation to s end data.
Check bellow picture for step 2:
thomasliul98518@ ahoo.com.cn salcséfiaosongcom Address: No.56 Renhe Road Renhe Town Baivun District Guangzhou China smit lbil dal 26us—28us fia—vo' VCC """"""""""" T—bitfififi‘ GND --------------- . | Mafia 1 | $355 —-1 50115 p— | {’fi'vtfifififlfi: — %fl1§% / us signal
Aosong(Guangzhou) Electronics Co.,Ltd---------------------------------------------------------------------------------------------------------------------
Tell: +86-020-36380552, +86-020-36042809 Fax: +86-020-36380562
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Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
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------------------------------------------------------------------------------------------------------------------------------------
Start transmit 1bit data Start transmit next bit data
26-28us voltage-length means data "0"
Host signal Sesnor's signal
Single-bus signal
------------------------------------------------------------------------------------------------------------------------------------
Step 3: AM2303 send data to MCU
When AM2303 is sending data to MCU, every bit's transmission begin with low-voltage-level that last 50us,
the following high-voltage-level signal's length decide the bit is "1" or "0".
Check bellow picture for step 3:
------------------------------------------------------------------------------------------------------------------------------------
thomasliul98518@ ahoo.com.cn salcs@aosong.com Address: No.56 Renhe Road Renhe Town Baivun District Guangzhou China fiffi‘u‘ I 1Bit3=Ffifi \ 1 $ ‘ 52 —-f 50us I‘— I 13%?ififii _ — ififii‘? D 355'
Aosong(Guangzhou) Electronics Co.,Ltd---------------------------------------------------------------------------------------------------------------------
Tell: +86-020-36380552, +86-020-36042809 Fax: +86-020-36380562
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Email: thomasliu198518@yahoo.com.cn sales@aosong.com
Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
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70us voltage-length means 1bit data "1"
Start transmit 1bit data Start transmit next bit data
Host signal Sensor's signal
Single-bus signal
------------------------------------------------------------------------------------------------------------------------------------
If signal from AM2303 is always high-voltage-level, it means AM2303 is not working properly, please check
the electrical connection status.
6.
6.
6.
6. Electrical
Electrical
Electrical
Electrical Characteristics:
Characteristics:
Characteristics:
Characteristics:
*Collecting period should be : >1.7 second.
7. Attentions
Attentions
Attentions
Attentions of
of
of
of application:
application:
application:
application:
(1) Operating and storage conditions
We
don't recommend the applying RH-range beyond the range stated in this specification. The DHT11 sensor
Item
Condition
Min
Max
Unit
Power supply
DC
3.3
5.5
V
Current supply
Measuring
1.3
2.1
mA
Average
0.5
1.1
mA
Collecting
period
Second
1.7
2
Second
thomasliul98518@ ahoo.com.cn salcs@aosong.com Address: No.56 chhc Road. chhc Town Baivun District Guangzhou. China
Aosong(Guangzhou) Electronics Co.,Ltd---------------------------------------------------------------------------------------------------------------------
Tell: +86-020-36380552, +86-020-36042809 Fax: +86-020-36380562
http://www.aosong.com
Email: thomasliu198518@yahoo.com.cn sales@aosong.com
Address: No.56, Renhe Road, Renhe Town, Baiyun District, Guangzhou, China
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can recover after working in non-normal operating condition to calibrated status, but will accelerate sensors'
aging.
(2) Attentions to chemical materials
Vapor from chemical materials may interfere AM2303's sensitive-elements and debase AM2303's sensitivity .
(3) Disposal when (1) & (2) happens
Step one: Keep the AM2303 sensor at condition of Temperature 50~60Celsius, humidity <10%RH for 2 hours ;
Step two: After step one, keep the AM2303 sensor at condition of Temperature 20~30Celsius, humidity
>70%RH for 5 hours.
(4) Attention to temperature's affection
Relative humidity strongly depend on temperature, that is why we use temperature compensation technology
to ensure accurate measurement of RH. But it's still be much better to keep the sensor at same temperature when
sensing.
AM2303 should be mounted at the place as far as possible from parts that may cause change to temperature.
(5) Attentions to light
Long time exposure to strong light and ultraviolet may debase AM2303's performance.
(6) Attentions to connection wires
The connection wires' quality will effect communication's quality and distance, high quality shielding-wire is
recommended.
(7) Other attentions
* Welding temperature should be bellow 260Celsius.
* Avoid using the sensor under dew condition.
* Don't use this product in safety or emergency stop devices or any other occasion that failure of AM2303
may cause personal injury.