RHT01 Datasheet, PDF (2/5 Pages) List of Unclassifed Manufacturers – Digital relative humidity & temperature sensor

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5. Electrical connection diagram:
6. Operating specifications:
(1) Power and Pins
Power's voltage should be 3.3-6V 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) Communication and signal
MaxDetect 1-wire bus is used for communication between MCU and RHT01. ( MaxDetect 1-wire bus is specially
designed by MaxDetect Technology Co., Ltd. , it's different from Maxim/Dallas 1-wire bus, so it's incompatible
with Dallas 1-wire bus.)
Illustration of MaxDetect 1-wire bus:
DATA=16 bits RH data+16 bits Temperature data+8 bits check-sum
Example: MCU has received 40 bits data from RHT01 as
0010 0001 0000 0000 0001 1010 0000 0000 0011 1011
16 bits RH data
16 bits T data
check sum
Here we convert 16 bits RH data from binary system to decimal system,
0010 0001 0000 0000 → 33
Binary system
Decimal system
RH=33.0%RH
Here we convert 16 bits T data from binary system to decimal system,
0001 1010 0000 0000 → 26
Binary system
Decimal system
T=26.0℃
When highest bit of temperature is 1, it means the temperature is below 0 degree Celsius.
Example: 1000 1010 0000 0000, T= minus 10℃
16 bits T data
Sum=0010 0001+0000 0000+0001 1010+0000 0000=0011 1011
Check-sum=the last 8 bits of Sum=0011 1011
When MCU send start signal, RHT01 change from standby-status to running-status.
When MCU finishs sending the start signal, RHT01 will send response signal of 40-bit data that reflect the relative
humidity and temperature to MCU.
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