Skip to content

Atividade

Contador de passos sensível

Intermediário | MakeCode, Python | Acelerômetro, Tela de LED | Corpo humano, Design do produto, Ferramentas de desempenho, Forças, Sensores

Passo 1: Projeto

O que é?

Um contador de passos que você pode tornar mais preciso, adaptando-o ao seu próprio estilo de caminhada

micro:bit preso ao sapato

O que você aprenderá

  • Como o micro:bit pode coletar dados numéricos de aceleração
  • How to apply thresholds to sensor data to trigger events like increasing a step counter

Como 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.

O que você precisa

  • micro:bit (ou simulador MakeCode)
  • Editor MakeCode ou Python
  • bateria (opcional)
  • algo para prender o micro:bit ao sapato ou perna - barbante ou velcro.

Passo 2: É hora de programar

Passo 3: Vamos melhorar

  • Make your batteries last longer by changing the program so it only shows the number of steps when you press button A.
  • Modifique o programa para que o botão B retorne o contador a 0.
  • Meça o comprimento do seu passo e faça o micro:bit multiplicar isso pelo número de passos para calcular a distância que você percorreu.
  • 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