AM (wired DHT22) temperature-humidity sensor . DHT11 datasheet (https ://)(in chinese, so see the DHT22 datasheet too!). AM digital temperature and humidity module is a digital output signal containing a calibrated temperature and humidity combined sensor. It uses a. AM Datasheet PDF Download – Digital temperature and humidity sensor, AM data sheet.
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The reference calibration sources are the same as before, eleven saturated solutions and distilled water. So long as you do not attempt to read the device serial number, these three sensors function identically. Readings were taken once every six seconds.
AM Datasheet PDF –
The membrane obscures a,2302 manufacturer’s mark on the left hand device, but reading the internal serial number shows it to be an Si I am not sure. It is a nice compact and apparently robust unit, especially with the optional cover screen. The data scatter is small and the calibration error is linear in both the humidity and temperature directions. For this test I am running one device each, with and without.
The smaller, round data datashwet are the published reference values. Almost vaguely related and possibly of interest is monitoring radon in the house.
However, for all devices except the Si and AM the effect is small and the width of the envelope is not larger than the scatter of data points already observed. In contrast, the AM device G shows little error as a function of humidity Figure 12 but has the largest error as a function of temperature Figure Currently I am attributing it to bad luck in my getting a couple of faulty devices rather than a systematic fault with this model.
DHT22 Sensor Pinout, Specs, Equivalents, Circuit & Datasheet
If the device caps output at 0— it makes it daatasheet to apply your own re-calibration near the limits. Within the data obtained here, the BME is the undisputed winner. AM F output saturates at Serial data Temperature Range: As far as I have been able to acertain, all the other devices are polymer capacitance hygrometers.
Either way the performance of the sensor is same.
First, unlike all the other devices tested it includes a barometer. Two complete cycles of the loop from wet to dry and back to wet were performed.
Blue shows low readings and red are high. The absolute errors were a little datasheey than advertised, but repeatability was good and the thermal dependence not too severe.
As previously noted, this is my cherry-picked, best AM from a sample of six. It is true though that all values will be slightly biases one way or the other as conditions change.
(PDF) AM2302 Datasheet download
The shaded grey region is the specified tolerance from the dtasheet datasheets. I discuss these together though they are distinct devices from two different manufacturers. In the right hand panel the lag has been arbitrarily removed and the values normalised in order to compare the intrinsic response speed of the sensor elements.
It has a very rapid response, good if you need it, but satasheet likely need filtering and smoothing if you are more interested in meteorological humidity.
AM2302 Datasheet PDF
Many thanks to Nava Whiteford who has sent me some scanning electron micrographs of what is inside the BME Absolute accuracy seems comparable to the other sensors apart from the BME The others all continue uneffected but values were only logged from this sensor when they were sensible. The hysteresis curve traces a tight envelope and was highly repeatable on the two cycles performed.
Similarly the Sensirion SHT21 not included here also has a near identical specification and interface.