ESP32 firmware providing a REST API for controlling the galileo science outreach setup

A ESP32 micro-controller to drive the galileo board experiment

This software package provides the ESP32 micro-controller firmware to drive the galileo board experiment.

Setup view

Web interface

HTML web interface

Doing the experiment

  • Install the four optical sensors either
    • at equal distances in order to see the acceleration, or
    • at increasing distances to obtain equal time intervals.
  • Stick the metal ball onto the electromagnet.
  • Press the button on the setup of the HTML interface Run button and observe the ball fall.
  • Press the HTML interface Get button at the motion end to get the detected times, velocities and accelerations.

Tutorial video:


  • The Start and Stop command are only used for debug.
  • The Get output is of the form
  "time": 0.000,        // Current time in second when the `Get` button is pressed.
  "start_time": 0.000,  // Experiment time in second, when the `Run` button is pressed.
  "detected_times": [0.000, 0.000, 0.000, 0.000], // Relative times of optical sensor detection, after start_time.
  "detected_velocities": [0.000, 0.000, 0.000],   // Times differences of optical sensor detection.
  "detected_accelerations": [0.00000, 0.00000]    // Times differences of times differences.
  • Result prediction:
    • The ball trajectory writes x(t) = k t^2, since the initial velocity is zero, and considering the electromagnet position as origin
      • with k = 1/2 g sin(alpha) ~ 1.5 when g = 9.81 m/s^2 is the gravity constant alpha ~ 15 deg is the board inclination.
    • In case of equal distances we expect the detected times and velocities to decrease, and accelerations to be similar.
    • In case of increasing distance we expect the detected times differences to be similar.


Package repository


This is a Node.js module, installed using the npmcommand line tools.

npm install git+


  • Refer to usage_galileo, for the Galileo mechanism web service usage.

npm script usage

npm install  : installs all package dependencies.
npm run build: builds the different doc and test files.
npm test     : runs functional and non-regression tests.
npm clean    : cleans installation files.
npm run sync : syncs the files with the git repository.


  • esp32gpiocontrol: ESP32 firmware providing a REST API for controlling the GPIO interface and higher functions

Dev Dependencies

  • aidebuild: Builds multi-language compilation packages and related documentation.