Data Sheet

Aosong(Guangzhou) Electronics Co.,Ltd. TEL：[phone] www.aosong.com
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Data format:
The 8bit humidity integer data + 8bit the Humidity decimal data +8 bit temperature integer data +
8bit fractional temperature data +8 bit parity bit.
◎Parity bit data definition
“8bit humidity integer data + 8bit humidity decimal data +8 bit temperature integer data + 8bit
temperature fractional data” 8bit checksum is equal to the results of the last eight.
Example 1: 40 data is received:
0011 0101 0000 0000 0001 1000 0000 0000 0100 1101
High humidity 8 Low humidity 8 High temp. 8 Low temp. 8 Parity bit
Calculate：
0011 0101+0000 0000+0001 1000+0000 0000= 0100 1101
Received data is correct：
Humidity：0011 0101=35H=53%RH
Temperature：0001 1000=18H=24℃
Example 2: 40 data is received:
0011 0101 0000 0000 0001 1000 0000 0000 0100 1001
High humidity 8 Low humidity 8 High temp. 8 Low temp. 8 Parity bit
Calculate：
0011 0101+0000 0000+0001 1000+0000 0000＝ 0100 1101
01001101≠0100 1001
The received data is not correct, give up, to re-receive data.
◎Data Timing Diagram
User host (MCU) to send a signal, DHT11 converted from low-power mode to high-speed mode,
until the host began to signal the end of the DHT11 send a response signal to send 40bit data, and
trigger a letter collection. The signal is sent as shown.
Data Timing Diagram
Note: The host reads the temperature and humidity data from DHT11 always the last measured
value, such as twice the measured interval of time is very long, continuous read twice to the second
value of real-time temperature and humidity values.