Digital humidity and temperature sensor-AM2302 AOSONG
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Your specialist in innovating humidity & temperature sensors Digital relative humidity & temperature sensor AM2302 1. Feature & Application: *High precision *Capacitive type *Full range temperature compensated *Relative humidity and temperature measurement *Calibrated digital signal *Outstanding long-term stability *Extra components not needed *Long transmission distance, up to 100 meters *Low power consumption *4 pins packaged and fully interchangeable 2. Description: AM2302 output calibrated digital signal. It applys 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(100m) enable AM2302 to be suited in all kinds of harsh application occasions. Single-row packaged with four pins, making the connection very convenient. 3. Technical Specification: Model Power supply Output signal Sensing element Operating range Accuracy Resolution or sensitivity Repeatability Humidity hysteresis Long-term Stability Interchangeability AM2302 3.3-5.5V DC digital signal via Aosong 1-wire bus Polymer humidity capacitor humidity 0-100%RH; humidity +-2%RH(Max +-5%RH); humidity 0.1%RH; humidity +-1%RH; +-0.3%RH +-0.5%RH/year fully interchangeable temperature -40~80Celsius temperature +-0.5Celsius temperature 0.1Celsius temperature +-0.2Celsius http://www.aosong.com Thomas Liu (Sales Manager) Email: thomasliu198518@aliyun.com , sales@aosong.com

Your specialist in innovating humidity A temperature sensors Pit ftqiHnc*- uujii(i-rr: I 2 J 4 (from U-fi I-J neb I dinctiuih]. 5. Electrical connection diagram: Rp is pull up resistor, when transmission distance beyond Power's voltage should be 3.3-5.5V 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 lOOnF can be added between VDD and GND for wave filtering. Aosong 1-wire bus is used for communication between MCU and AM2302. ( Aosong 1-wire bus is specially designed by Aosong Electronics Co.,...

_Your specialist in innovating humidity A temperature sensors DATA=16 bits RH data+16 bits Temperature data+8 bits check-sum Example: MCU has received 40 bits data from AM2302 as 16 bits RH data 16 bits T data checksum Here we convert 16 bits RH data from binary system to decimal system, Binary system Decimal system Here we convert 16 bits T data from binary system to decimal system, Binary system Decimal system When highest bit of temperature is 1, it means the temperature is below 0 degree Celsius. Check-sum=the last 8 bits of Sum=1110 1110 When MCU send start signal, AM2302 change from...

_Your specialist in innovating humidity A temperature sensors Data-bus's free status is high voltage level. When communication between MCU and AM2302 begins, MCU will pull low data-bus and this process must beyond at least l~10ms to ensure AM2302 could detect MCU's signal, then MCU will pulls up and wait 20-40us for AM2302's response. When AM2302 detect the start signal, AM2302 will pull low the bus 80us as response signal, then AM2302 pulls up 80us for preparation to send data. See below figure: Start data transmission Host's signal Sensor's signal 2). Step 2: AM2302 send data to MCU When...

Your specialist in innovating humidity & temperature sensors Attention: If signal from AM2302 is always high-voltage-level, it means AM2302 is not working properly, please check the electrical connection status. 7. Electrical Characteristics: Items Condition Min Typical Max Unit Power supply DC 3.3 5 6 V Current supply Measuring 1 1.5 mA Stand-by 40 Null 50 uA Collecting Second 2 Second period 8. Error and sources of error: Measure values maybe influenced by follow factors: Humidity errors Equilibration time too short, steam, water sprays, dripping water or condensation at the sensor, etc....

Your specialist in innovating humidity & temperature sensors 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. AM2302 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 AM2302's performance. (6) Attentions to connection wires The connection wires' quality will effect communication's...