Assignment 5: Input and Output

Objective: Learn about the different types of input and output devices.
Time: 1,5 hour

Part 1: Input

Input is measured by sensors. There are many types of sensors that could each measure a unit (put in brackets in the list below):

  • FSR (pressure)
  • LDR (light)
  • Accelerometer (acceleration)
  • Temperature sensor (temperature)
  • Tilt switch (conductance)
  • Magnetometer (earth magnetic field, orientation)
  • Switch (on/off value)
  • Camera (light)
  • Microphone (audio)
  • Sonar (high frequency audio)
  • Ultrasound (flow, liquids)
  • Touch (pressure)
  • Strain gauge (torsion)
  • Piezo (torsion with change in shape)
  • Flow sensor (flow)
  • GSR (wetness of skin)
  • Pulse sensor (pulse of our heart)
  • EEG (brain frequencies)
  • EMG (electrical activity of muscles)
  • EOG (eye movement)
  • Radiation sensor (radiation)
  • Humidity sensor (humidity)
  • Altitude sensor (altitude)
  • FLEX sensor (bending movement)
  • Gyroscope (angular velocity)
  • Slider (value in a range)

We can organise sensors in two ways:

  1. Based on what is measured (e.g. group all force sensors together)
  2. Based on the technology used in that sensor

Sensorwiki is one of the best information sources about sensors and is organised in the first way.

If we, as an example, take a linear potentiometer (slider) and try to connect it to Arduino, we will find out that some things are not as straightforward. This sensor maps position to resistance, but Arduino works with output voltages. That’s why we need to convert the range of resistance values into a voltage:

Position -> Resistance -> Voltage

Other problems include the high voltage that sensors (e.g. Piezo) can have. For those situations, a buffer need to be used. Lastly, it also matters if a sensor maps to analog or digital output. Nowadays accelerometers map to digital output.

Part 2: Output

We made a fairly similar list of output devices that one can use:

  • LED (light)
  • Piezo (sound, vibration)
  • Speaker using electromagned (sound)
  • Video screen (graphics)
  • Motor (movement)
  • Solenoids (used for relays and switches where something needs to be pushed up or down)
  • Heating element (heat)
  • Ultrasound (audio, flow)
  • Muscle wire (wire that actuates and changes length)
  • Haptic illusions (e.g. that a surface feels rough)

 

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