Velleman MM102 User manual

USER MANUAL AUGUST 2016
MM102
Red wire
5V positive
power supply
Black wire
GND negative
power supply
Yellow wire
Humidity output /
data request
ANALOG HUMIDITY SENSOR BOARD
This breakout board is equipped with a hygrometric sensor, thus
it lends itself to detect the moisture found in the environment it is
placed in. It operates at a very low voltage (it correctly operates at
up to 5.5 Vcc) and typically absorbs 200 microamperes: it is thus
ideal even in applications that are battery powered, and in which a
minimal absorption is required.
The HIH-5030-001 sensor has the great virtue of supplying an
analog output signal, consisting in a DC voltage that varies in an
almost linear manner, as the relative humidity (RH) varies; thus it
may be interfaced both to analog circuits that check the air ow of
a dehumidier installation, and it may be read by an A/D converter
or by a microcontroller’s input that is supplied with an analog/digital
converter.
The device’s sensor component is of the capacitive kind, and it is
composed of thermosetting polymers that have been cut with a la-
ser. The signal’s conditioning circuitry, integrated on a chip, is found in
the integrated circuit. The multilayer construction of the sensitive ele-
ment provides an excellent resistance to the greatest part of the risks
coming from applications such as, for example, condensation, dust,
lth, oils and common chemical products found in the measurement
environment.

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The measurement accuracy is ÷3%, given that the relative humidity is between 11% and 89%; the response time
to the humidity variations is of about 5 seconds. The variation curve for the device’s output voltage, as a function of
the relative humidity (having a 3.3 V power supply and an environmental temperature of 25° C) is shown in Fig. 1.
The component’s output is an high impedance one, and may pilot circuits having an impedance of no less than
65 kohms; otherwise the voltage supplied as a function of the humidity may not react to the curve shown in Fig.
1, but will vary in a different manner. In addition to the A/D converter, the device’s output may be connected to a
microampere meter having a pointer, or to an opportunely calibrated voltmeter, so to create a veritable hygrom-
eter, from which to obtain a direct indication of the relative humidity.
HIH-5030-001 sensor’s output voltage, as a function of the detected relative humidity.