S3238806 Humidity and temp sensor report - project 3
From Physical Programming
SENSOR TECHNOLOGY REPORT – HUMIDITY AND TEMPERATURE SENSOR
What is humidity? Humidity is the percentage of the amount of moisture in the air compared to what the air can hold at that certain temperature. Usually warmer air can hold more moisture than cooler air can. The humidity scale is measured from 0 – 100.
Why do we care about the moisture content in the air? We may not realize it but the humidity affects a lot of things in many ways; people, animals, plants, and inanimate objects, having too high or low humidity can have negative effects. So to keep monitor of the humidity to the right level so that it doesn’t affect our health too much, plants not growing diseases, electronics, housing doesn’t get damaged, humidity sensor is used. An existing product that measures the moisture content in the air is the hygrometer. This works by leaving the device in an exposed environment and the device will read the air moisture content. It can be used in places such as in the home, green houses, industrial spaces, saunas, humidors, museums, coating industries and more where keeping a certain level of humidity is essential.
For this project we will be dealing with the Arduino microcontroller, here we will be using the basic Arduino board; Arduino Duelmilanove (aka, Arduino Main Board). The Arduino is capable of sensing its environment by receiving an input from a variety of sensors and perform some sort of an output. Here we will connect the humidity sensor to the Arduino, a humidity sensor can be a sensor with itself but it is usually combined with a temperature sensor as well, an example of a combined sensor from Modern Device.
To gain a better understanding of the different components of this sensor, there is a SHT21 digital and temperature sensor from Sersirion, which measures the moisture content. This is placed purposefully on the 14-bit sensor on the far end to get a better reading of the environment because when the sensor is attached to the Arduino the circuit heat can affect the results. This sensor is Arduino compatible. How this sensor can be interfaced with an Arduino micro-controller is the four pins on the sensor connect the two devices, the pins are inserted into the Arduino 12C protocol, and digital data is transmitted here. The sensor is designed to operate directly off the supply voltage coming from the Arduino, because the sensor is so small it consumes very little power. Some sort of output device is then connected to the Arduino, this could be a separate LCD screen or it could connect straight to your computer via USB connection. After the setup a coding is inputted and the humidity sensor is ready to be run and measure!
If we were to connect temperature sensor and humidity sensor separately to the Arduino, wires and breadboards would need to be used to run the device, here is an example of how it would be connected.
http://www.instructables.com/id/Arduino-Temperature-Humidity/
Some examples of interactive projects using this sensor technology:
“Antipasto Hardware Blog” – Created a project which maps out the relative humidity and temperature as a bar graph on the TouchShield Slide.
http://antipastohw.blogspot.com/2010/05/up-and-running-on-humidity-sensor.html
“Garduino: Gardening + Arduino” – Created a project where it waters plants whenever the soil moisture drops below a predefined value, turns on grow lights in the dark and alerts the user when temperature around the plant drops below 50 degrees.
http://www.instructables.com/id/Garduino-Gardening-Arduino/
“Circuit Lake” – Created a project using USB wireless humidity and temperature sensor.
http://www.circuitlake.com/usb-wireless-temperature-and-humidity-sensor.html
Created a project in making their own weather station.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1264143673
References
Modern Device, 2010, Humidity and Temp Sensor http://www.moderndevice.com/products/humidity-and-temperature-sensor
Antipasto Hardware Blog Open source Hardware at Liquidware, 31 May 2010, Up and running on the Humidity Sensor http://antipastohw.blogspot.com/2010/05/up-and-running-on-humidity-sensor.html
Arduino Forum, 22 January 2010, Humidity Sensor http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1264143673
Instructables, 15 December 2008, Garduino: Gardening + Arduino http://www.instructables.com/id/Garduino-Gardening-Arduino/
