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Sense-Compute-Communicate-Actuate

Part 2: Sensors

The Humble Camera

Source: Khan Academy course “Pixar in a Box”
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  • The Pinhole Camera: https://youtu.be/jhBC39xZVnw
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  • Camera Lenses: https://youtu.be/Q5Jat06VM6o

    • The Smartphone Camera

    Source: Structure and Imaging Principles of a Smartphone Camera
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  • Article: https://www.utmel.com/blog/categories/optoelectronics/structure-and-imaging-principle-of-smartphone-camera
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  • Video: https://youtu.be/fkG3D0WXRAw

    • Infrared Camera

    Typically, the human eye can detect wavelengths from 380 to 700 nanometers. Infrared (IR) has wavelengths between 780 nm and 1 mm.
    While traditional visible-light cameras capture images of objects radiating light visible to the naked eye, an infrared camera captures what the human eye cannot see.

    Applications

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  • Electricians and building inspectors utilize IR technology to detect deterioration, corrosion, leaks, and other potential dangers.
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  • Thermal imagers are useful to monitor any mechanical and electrical equipment.
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  • medical professionals can look at infrared image of the human body
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  • researchers can study characteristics of new materials and product

    • LIDAR

    What does a 3D point cloud represent: https://youtu.be/2crAfWZOgf0
    ​

    Things to know about LIDAR

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  • What does LIDAR stand for?
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  • How does LIDAR measure distance?
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  • Can LIDAR detect size and shape of objects?
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  • What older technology is LIDAR similar to? How is LIDAR different from that technology?
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  • How is LIDAR a privacy-preserving technology?
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  • Why would some one use LIDAR instead of video?
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  • Name a few applications of LIDAR

    • Microphone

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  • How does a microphone work? https://www.youtube.com/watch?v=d_crXXbuEKE

    • IMU: Inertial Measurement Unit

    An inertial measurement unit (IMU) is a sensor that tracks the acceleration and angular velocity of an object over a period of time. if needed it can also track the Earth’s magnetic field. It provides real-time motion detection, indoor navigation, gesture and activity recognition as well as optical image stabilization (OIS).

    Things to know about IMUs

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  • Three types of sensors (usually)
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  • Accelerometer: measures velocity and acceleration
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  • Gyroscope: measures rotation and rotational rate
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  • Magnetometer: establishes cardinal direction (directional heading)
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  • These sensors are a type of MEMS (Micro ElectroMechanical Systems)

    • Applications

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  • It is used in smartphones and tablets to analyze the user’s movement.
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  • IMUs are used in headsets to track head orientation and in handheld controllers to capture hand movement
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  • In sports, this powerful technology can be used to capture and analyze athletes’ movements
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  • On manned and unmanned aircrafts, an IMU’s measurements can be used to calculate altitude and relative position
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  • IMUs serve as a supplement to GPS positioning systems, allowing the navigational device to continue with an estimated position and heading if it loses satellite connection.

    • GPS: Global Positioning System

    How does it work: https://youtu.be/70cDSUI4XKE
    (Resume at this point )

    Things to know about GPS

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  • Works with the help of a system of satellites. There are over 30 satellites used for GPS, orbiting over 16,000 miles (26,000km) above the Earth!
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  • Control centers on the ground make sure that the satellites operate properly.
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  • These satellites communicate with receivers. A receiver might be in your smartphone, car, or computer
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  • Receivers get signals from satellites. The signal usually contains the time from the satellites’ “atomic clock”.
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  • Receiver figures out how long it took the signal to arrive from the the satellite. It knows the speed of the signal (speed of light about 300,000,000 m/s). it computes
    Distance = signal speed x signal time
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  • GPS receiver needs signals from at least three satellites to find its position - using a process called Trilateration.
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  • Currently, a GPS-enabled smartphone usually knows your location within about 5 metres.
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  • What sort of problems do you face when using GPS?

    • To know more:

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  • The math behind GPS: https://letstalkscience.ca/educational-resources/backgrounders/math-behind-gps
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  • Who better than Garmin to talk about GPS: https://youtu.be/AUetJyTDUFY
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  • Gladys Mae West, American mathematician known for her work contributing to the development of the Global Positioning System (GPS). https://www.youtube.com/watch?v=McIemoQWv64&t=11s
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