Weather Station project
Use: Determining the likeliness of rain fall.
Relationship between Humidity and Rainfall:
Humidity is the amount of water vapour present in the air.
When the air becomes saturated with water vapour and can no longer absorb anymore vapour, the water condenses into clouds.
Temperature Limits Humidity
The temperature of a parcel of air puts a limit on how much water vapour (humidity) the parcel of air can hold. The warmer the air, the more water vapour it can hold. By the same token, cold air can hold significantly less water vapour than warm air.
Humidity Responds To Temperature
Humidity is water vapour contained in air. At higher temperatures, air can hold more water vapour than the same amount of air at lower temperatures. For example, if a sealed parcel of air experiences a rise in temperature with no addition of water vapour, the relative humidity of the parcel of air decreases because the warmer air is capable of holding more water.
Relative Humidity Is Based On Temperature
The relationship between temperature and humidity is often expressed by a percentage called relative humidity. Relative humidity is the ratio of water vapour present in air at a given temperature relative to the maximum amount of water vapour the air at that temperature could hold.
Temperature is a variable which effects Humidity
Cold = Less water vapour absorbed
Hot = More water vapour absorbed
Environmental Monitoring projects
Use: Making sure environmental conditions are maintained when Farming/Growing produce which requires specific conditions to grow.
Various sensors can be set up in a controlled farming environment to monitor variables which effect plant growth. The data collected by these sensors can be compared with optimal readings and thus can be used to determine whether any of the variables require optimisation.
Variables involved in plant growth:
Light – Lighting
Temperature – heating/electric heater/ventilation system
Water/moisture content in soil – water pump
Humidity – ventilation system
Light – Light Sensitive Diode can be used to monitor the light levels in the plant environment and a group of LEDs located around the plant, can be switched on when the light levels go below a certain point.
Readings fall below optimal levels – Flick switch to increase light or switch on additional lighting.
Readings go over optimal levels – Flick which to decrease or turn off additional lighting.
Temperature –Humidity sensor can be used to monitor the temperature levels in the plant environment.
Readings fall below optimal levels – Flick switch to activate heater and increase temperature or switch on additional heating.
Readings go over optimal levels – Flick switch to decrease or turn off additional heating.
Moisture –Moisture sensor can be used to monitor the amount of moisture in the soil.
Readings fall below optimal levels – Flick switch to activate water pump which feeds into the soil.
Readings go over optimal levels – Flick switch to decrease or turn off additional watering system.
Humidity –Humidity sensor can be used to monitor the amount of water vapour in the plants environment.
Readings fall below optimal levels – Flick switch to activate heater and increase temperature or switch on additional heating + Flick switch to activate water pump which feeds into the soil.
Readings go over optimal levels – Flick switch to decrease or turn off additional heating. + Flick switch to decrease or turn off additional watering system.
Bathroom Extractor Fan
Detects moisture content in the air – Switches on extractor fan when humidity breaches a certain threshold. Potential for adding LEDs into circuit to indicate where humidity readings are between thresholds.
This weeks Testing!….
Chosen Collaborative Project idea:
Bathroom Extractor Fan
Detects moisture content in the air – Switches on extractor fan when humidity breaches a certain threshold.
Reed Switch Module – Mechanical Switch
Humidity Sensor DHT11 – Moisture Sensor
Flow Chart for Circuit
Building the Circuit:
DHT11 Humidity Sensor + REED Switch
Red = VCC
Green = DATA
Black = GROUND
Pin 12 = DHT11 Humidity Sensor
Pin 2 = REED Switch (Magnet activated)
Breakdown of code:
Short video clip:
Tune in next week for more developments..