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Week9 - Input Devices

Missions of my week8 assignments:​

What should I achieve in this week:​

Group Assignment​

  • Probe an input device's analog levels and digital signals

Individual Assignment​

  • Measure something: add a sensor to a microcontroller board that you have designed and read it

Notes about Input Device​

Get singal into the microcontrollers, the input devices.

The communication/protocols: ports, comparator, A/D, I2C

I2C: SCL and SDA, two pull up registors

Switch: button, switch - for more detailed, once you push the button, there will be some bounces.

Magnet: hall effect sensor, current will change from the magnetic field, there are a 3D type - output/sensing the x,y,z about under the magnetic field - joy sticks, gaming system

Potentiometer: variable resistor

Step response: touch pad - sensing the postion of the pad, LVTD

  • Series connection with 1M resistor and line, there are magentic field between plates.
  • Measuring the chaning curve of the time/voltage, fix the time and measure the voltage, or fix the voltage and measure the time
  • XIAO RP2040 includes PIO which is a main processor and 8 federated processors
  • Ensure the design that can protect the inner components
  • Loop setting, settling time, avliding noise hint: using comparator to measure the current/voltage for there might be some distance in the PCB

Temperture: the resistor is depending on the temperature, once connected, measure the current or voltage

  • The "bridge": measure the small change, connect the "bridge" with a amplifier

Light: the resistor is depending on the light, once connected, measure the current or voltage

  • There are different types of light sensor, can measure differnt lights, reflection

Motion: the radar, sending the signals to the object and measure the save feedback, to see whether is moving

Distance: like radar, transmit the light and then receive finally output

Location, time: thanks to the addtional function module, once connected, the signal will send automatically

Acceleration: 9-axis IMU(inertial measurement unit) - 3 accelerometer for x, y, z, 3 gyroscope for xyz and 3 magnetometer for magnetic field - absolute oritentation. 6-axis IMU just 3 accelerometer and 3 gyroscope ; 3-axis IMU just 3 accelerometer.

Sound: microphone measure audio.

  • I2S(I2C-similar) - specifically for sound, the commonication protocols, which means using SDA SCL, I2S Arduino library.

  • Microphone on the bottom, not the top of the package

  • electrect is obsolete

Vibration: knock on the door, shake something, tab on the door

Force: the push, resistor can change by the pressure

Angle: differnt point

Pressure: more for air pressure, for the human pressure is force

try to make the ground is not far way from the sensor, for the interface - protection design

Pulse: heartbeat sensor

Air-pollution: chemical reaction

Image: like the camera sensor on XIAO ESP32S3 Sense

  • OpenCV is the most poopluar libraries for camera sensing
  • WebRTC: create a serial port from the brower (Thess.js)