Please add support DHT22 Sensor

[khajievN]

Please add DHT22 temperature sensor in this driver.

[SergiyKorotun]

+1

[gmarat13]

+1

[emmynet]

+1

[emmynet]

I think it is not possible to implement a driver for this sensor for the GPIO speed transmission constraints.

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from: androidthings.rocks

In the Native SDK the GPIO speed is 0.15ms , which is still 150μs and nowhere near the 20-40μs required by the sensor.

Android Things and the fact it uses Linux, which is not a real-time operating system.
A conversation with a member of the Android Things team suggested the following:

Your not likely to get consistent sub-1ms timing at the application layer. If the data on the wire is timed the same as a UART, you might be able to write/read using a custom baud rate (thats ~25K baud). Otherwise you’ll probably have to implement it on an MCU.

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I tried to do a porting of rasbian c++ code but the Gpio::setValue(..)/Gpio::getValue() speed is high (150μs).

I think that if we use Native PIO, we have the same result.