Datasheet for the AM2301 digital temperature and humidity sensor, a 577 KB PDF. The AM2301, also sold as DHT21, uses a single-wire bus with a proprietary timing protocol. The document details wiring colours or pins, the data frame format with checksum, measurement ranges and accuracy, and supply voltage. Use it when servicing thermostats, incubators and climate controllers. Check the pull-up resistor on the data line and the cable length when readings fail or come back with checksum errors.
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