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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.

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.