Sensors+for+example,+heat+proximity,+magnetism,+light,+humidity,+Ph

=Strand 3: IT Systems=

Sensors for example, heat proximity, magnetism, light, humidity, Ph
**Sensors are used to detect various physical quantities, such as temperature, pressure, sound, light etc. Sensors are connected to the computers using an interface with special software e.g. the Vernier Sensors we use in the physics Lab. The data collected from the sensors can be displayed in several different ways e.g. graphs.**


 * Different types of sensors available are;**

**Temperature sensor:** One of the most common sensors is the temperature sensors. They are mainly used in cold countries to keep the temperatures constant of a central heating system.

**Proximity sensor:** A proximity sensor is made up of two halves. If the halves are moved away from each other, a signal is activated. Proximity sensors are mainly used on windows frames and doors in order to activate a signal when the objects are moved apart. The most common application of proximity sensors are for security purposes.

**Light sensor:** A light sensor has many uses. It can turn on lights in homes or streets when it becomes dark. It can also be used to detect the amount of light reflection of a barcode in an E.P.O.S. /P.O.S. terminal.

A humidity sensor is used to determine the amount of moisture present (in the atmosphere or soil).
 * Humidity sensor: **

A pH sensor is used to find out how basic or alkaline a solution is. It can be used for agricultural purposes or in sciences labs. A position sensor detects the angle of a spindle. It could be used to feedback the position of a robot arm.
 * pH sensor:**
 * Position sensor:**

**Mercury tilt switch:** If a device is tilted or moved, a blob of mercury in the switch also moves to complete the circuit. Mercury tilt switches can b used in pinball machines to check if someone is tilting the machine or in vending machines to trigger alarms.

Push switches are used in cars or fridges to switch on lights when the doors are open.
 * Push switch:**

**Sound sensor:** These types of sensors are used to detect the loudness/amplitude of the sound levels in decibels. Environmental health officers often use them to detect sound levels in Clubs, Residence areas etc. where loud music is often played.

The medical condition of a patient in an intensive care unit can be continually monitored using sensors connected to the patient. Respiration, blood pressure, temperature and electrical activity of the heart and pulse can all be measured by the sensors. A computer is used to continually monitor the results from the sensors and if the patient’s condition changes suddenly or values exceed given thresholds then an alarm sounds to alert medical staff.
 * Application of sensors in real life situations:**