DHT22 for room thermohygrometer

how wide is the measuring area (meter square) [m²] of a dht22 sensor?

The sensor can only measure the temperature of the air that is touching it so only a few square millimeters and certainly not metres

What application are you thinking of using the sensor for ?

For a room, a cultivation room (Green house)
So , how much sensors needed for that application

How big is the greenhouse ?
Are you aiming to control the temperature of the greenhouse or just measure it ?

If you circulate the air in the room and can control the temperature by means of heating, cooling and ventilation then you only need one sensor

How much control over the environment do you have ?

The area is 35m² and 2 meter high

Yes i want to control the humidity an temperature

Only one mcu in the environtment

Do you have referrences about? Article or something?

This may help;


greenhouse air circulation

Tom... :smiley: :+1: :coffee: :australia:

No, just my common sense

Where are you stuck at the moment ? Can you read the temperature and humidity from the sensor and display them on the Serial monitor ?

How are you doing to alter the environment ?
Heating ?
Cooling ?
Ventilation ?

Suppose the temperature is outside the target range then what are you going to change to bring it back into range ? Same question for humidity

I expect that there will be a interaction between the temperature and humidity, ie change one and the other one changes too. How are you going to deal with that ?

I just want to make sure that the sensor reading is represented condition of humidity and temperature in all area of green house. Cause i only used one sensor for a room.

I doing ventilation with fan and cooling with water mist pump

in this project focuses on controlling humidity than the impact of the process on changes in temperature values will be tolerated


Well keep the sensor away from any direct flow from the water mist, as this will degrade the sensor very quickly.
If you have ventilation, also make sure you have circulation of air around the greenhouse when the ventilation is off.
With good circulation you will only need one sensor to measure humidity and air temperature.

Can you post a plan of your greenhouse, showing where your ventilation and water mist is located and size of the building?

Tom... :smiley: :+1: :coffee: :australia:

For that condition mcu will activate a mist pump to bring the condition on range

The greenhouse size is 5 meter x 7 meter and 2 meter high. Fan will be install on two side of green house and nozzle will be install a long as greenhouse with ten points of mist nozzle

Thanks for your insight

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