Measurement Class Reference
Measurement API Reference

The measure module provides hardware level measurement.


Some electrical parts or circuits accept "pulse" and echo the "pulse" after delay.
This module is best suited for measuring that delay.

This module generates one pulse shot on an io, then measures the response time.

pulse generation

You can choose below to generate a pulse

  1. io_pulse: io number to generate pulse
  2. pulse: "positive" or "negative"
  3. pulse_width: pulse duration in values between ms. 0.001 to 1000.

Response measurement

You can choose below to measure response

  1. io_echo: io for measuring response
  2. measure_edges: maximum number of edges to detect. 1 to 4.
  3. timeout: timeout in ms, and default is 1000. 0.001 to 1000.
  4. callback: callback function after measurement or timeout

A callback function will be called when the edge count = measure_edges or timeout.
It has an array of edge information. For example, if you get a response like below

measure.echo() starts measurement.

// Javascript Example

  io_pulse: 0, // io for generate pulse
  io_echo: 1, // io to be measured
  pulse: "positive", // generate pulse pattern
  pulse_width: 0.1,  // generate pulse width
  measure_edges: 3, // 1 to 4. maximum edges to measure
  timeout: 1000, // this is optional. 1000(1sec) is default
  callback: function(edges) {
    // callback function

then, you will get below

// Javascript Example

callback: function(edges) {
  edges.length // == 2
  edges[0].edge // == true
  edges[0].timing // == t1
  edges[1].edge // == false
  edges[1].timing // == t2