# micro:bit專題 | 中等程度專題

## Sensitive step counter
### Step 1: Make it
What is it?
A step-counter you can make more accurate by tailoring it to your own walking style.

micro:bit attached to shoe
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
How it works
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.
What you need
micro:bit (or MakeCode simulator)
MakeCode or Python editor
battery pack (optional)
something to attach the micro:bit to your shoe or leg – string or Velcro.
### Step 2: Code it
MakeCode

### Step 3: Improve it
Make your batteries last longer by changing the program so it only shows the number of steps when you press button A.
Modify the program so button B sets the counter back to 0.
Measure the length of your step and get micro:bit to multiply this by the number of steps to calculate the distance you’ve walked.
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

###### tags: `micro:bit 中文學習資源`