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Actividad

Sensitive step counter

Intermedio | MakeCode, Python | Acelerómetro, Pantalla LED | Cuerpo humano, Diseño de producto, Fuerzas, Herramientas de rendimiento, Sensores

Paso 1: Hazlo

¿Qué es?

Un podómetro que puedes hacer más preciso por personalizarlo según tu propio estilo de caminar.

la micro:bit conectada a un zapato

What you’ll learn

  • How the micro:bit can collect numerical acceleration data
  • How to apply thresholds to sensor data to trigger events like increasing a step counter

Cómo funciona

  • 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.

Qué necesitas

  • micro:bit (o simulador MakeCode)
  • Editor de MakeCode o de Python
  • pilas (opcionales)
  • something to attach the micro:bit to your shoe or leg – string or Velcro.

Paso 2: Prográmalo

Paso 3: Mejóralo

  • Make your batteries last longer by changing the program so it only shows the number of steps when you press button A.
  • Modifica el programa para que el botón B reinicie el contador a 0.
  • Mide cuánto recorres con cada paso, y haz que el micro:bit lo multiplique por el número de pasos para mostrar la distancia total recorrida.
  • 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