Download to read offline
an overview of optical sensor and its application .pptx
- 1. Optical Sensors UST Done by: ShaimaAl-Ahdal Abrar Mohammed Malak Nassar Buthainah AL-Dubai Nov 2021 Under supervision of: Dr.Zaid Alhajj
- 2. Content What we aregoing to learn: 01 Definition of sensor 02 What are optical sensors 03 Operating Principle 04 Why optical sensors 05 Purposes of optical sensor 06 Usage of optical sensor 07 Types of optical sensor 08 Applications
- 3. What is a sensor? a device that responds to a physical stimulus (such as heat, light, sound, pressure, magnetism, or a particular motion) and transmits a resulting impulse (as for measurement or operating a control)
- 4. What is Optical sensor ? Itis a sensor that converts light rays into an electronic signal.
- 5. The operating principle: isthe transmitting and receiving of light in an optical sensor, the object to be detected reflects or interrupts a light beam sent out by an emitting diode. THE OPERATING PRINCIPLE
- 6. Why optical sensors;advantages: 1 Sensitivity 2 Free of EMI and RFI 3 Compact 4 Broadband 5 Electrical isolation 6 Wide range spectrum provides unique applications
- 7. Purpose to measure aphysical quantity of light and, depending on the type of sensor, then translates it into a form that is readable by an integrated measuring device
- 8. Usage • For contact-lessdetection • counting • positioning of parts.
- 9. Photoconductive devices usedto measure the resistance by converting a change of incident light into a change of resistance. The photovoltaic cell (solar cell) converts an amount of incident light into an output voltage. The Photodiodes convert an amount of incident light into an output current. Types of optical sensor Phototransistors are a type of bipolar transistor where the base-collector junction is exposed to light. This results in the same behavior of a photodiode, but with an internal gain.
- 10. Types of opticalsensors
- 11. Types of optical sensors’ system 1. Through-BeamSensors 2. Retro-Reflective Sensors 3. Diffuse Reflection Sensors
- 12. 1. Through- Beam Sensors The system consistsof two separate components: the transmitter and the receiver are placed opposite to each other. The transmitter projects a light beam onto the receiver. An interruption of the light beam is interpreted as a switch signal by the receiver. It is irrelevant where the interruption occurs. Advantage: Large operating distances can be achieved and the recognition is independent of the object’s surface structure, color or reflectivity.
- 13. 2. Retro- Reflective Sensors Transmitter andreceiver are both in the same house, through a reflector the emitted light beam is directed back to the receiver. An interruption of the light beam initiates a switching operation. Where the interruption occurs is of no importance. Advantage: Retro-reflective sensors enable large operating distances with switching points, which are exactly reproducible requiring little mounting effort. All objects interrupting the light beam are accurately detected independently of their surface structure or color.
- 14. 3. Diffuse Reflectio n Sensors Both transmitterand receiver are in one housing. The transmitted light is reflected by the object to be detected. Advantage: The diffused light intensity at the receiver serves as the switching condition. Regardless of the sensitivity setting the rear part always reflects better than the front part. This leads to the consequence to erroneous switching operations.
- 15. Medical Applications Biomedical Applications: Optical sensorshave robust applications in the biomedical field. Some of the examples are Breath analysis using tunable diode laser, Optical heart-rate monitors an optical heart-rate monitor measures your heart rate using light. A LED shines through the skin, and an optical sensor examines the light that reflected back. Since blood absorbs more light, fluctuations in light level can be translated into heart rate. This process is called as photoplethysmography
- 16. Any question ? Thankfor listening
- 17.