Skip to content

Aktivnost

Osjetljivi brojač koraka

Srednji | MakeCode, Python | LED zaslon, Mjerač ubrzanja | Alati za poboljšavanje performansi, Dizajn predmeta i produkata, Ljudsko tijelo, Senzori, Sile

1. korak: Napravi

Što je to?

Brojač koraka možeš učiniti preciznijim ako ga prilagodiš svom načinu hodanja.

micro:bit pričvršćen na cipelu

Naučit ćeš

  • Kako micro:bit prikuplja numeričke podatke za ubrzanje
  • How to apply thresholds to sensor data to trigger events like increasing a step counter

Kako to radi

  • The Step counter and Low energy step counter projects use the ‘shake’ gesture to count steps. The 'shake' gesture uses several accelerometer sensor readings to decide if the micro:bit has been shaken.
  • You may find that the ‘shake’ gesture isn’t triggered every time you take a step, or that it’s triggered too easily, leading to inaccurate counting of steps.
  • To make a more accurate step counter, instead of using the ‘shake’ gesture, this program uses numerical data from the accelerometer to decide whether you’ve taken a step and, if you have, increase the steps variable by 1.
  • If the acceleration is greater than (>) 1500, the steps variable is increased by one and show the step count on the LED display output. 1500 is the threshold – the point at which a movement will trigger a step to be counted.
  • You may need to change the 1500 number to make the step counter more accurate – but you can decide what threshold to use, whereas with the ‘shake’ gesture the threshold has been decided for you by the people who designed the micro:bit.
  • Modifying the threshold to work for you is called calibration.
  • Note that when micro:bit is not moving, the accelerometer gives a strength reading of about 1000. This is caused by the Earth’s gravity pulling down on the micro:bit.

Što ti treba

  • micro:bit (ili MakeCode simulator)
  • Uređivač MakeCode ili Python
  • baterije (prema potrebi)
  • something to attach the micro:bit to your shoe or leg – string or Velcro.

2. korak: Kodiraj

3. korak: Unaprijedi

  • Make your batteries last longer by changing the program so it only shows the number of steps when you press button A.
  • Promijeni program tako da tipkom B vratiš brojač na 0.
  • Izmjeri duljinu svoga koraka pa neka micro:bit pomnoži taj broj s brojem koraka kako bi izračunao daljinu koju si prešao.
  • The accelerometer can measure forces in 3 dimensions, called the X, Y and Z axes. You can modify the code to choose which axis to measure, depending on which way up you fix your micro:bit to your leg or shoe.
image showing X axis across front of micro:bit, y axis up and down, z axis running back to front