Demo code running on ESP32 micro, showing FreeRTOS concepts + MQTT + LED Strip + Accelerometer
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
components
main
.gitignore
LICENSE
Makefile
README.md

README.md

README

This repo contains the source code for a system of MQTT networked ESP32 based devices used to demonstrate various RTOS concepts for a local Nashville TN microcontroller meetup. The original event details are here: https://www.meetup.com/NashMicro/events/236602045/

Additionally, it was fun to play around and learn more about the ESP32 and MQTT.

Features:

  • A handful of fun LED Strip patterns
  • Builds including an Accelerometer will issue an MQTT event when tapped/bumped and also light up the LED Strip.
  • All builds subscribe to a Pattern MQTT event, enabling the ability to remotely change the LED Strip lighting pattern.
  • Builds without an accelerometer subscribe to an Accelerometer topic, and will light up their LED Strip when that topic is hit.
  • Some code modules written specifically to demonstrate various FreeRTOS concepts. Listed later in this readme document.

Target Hardware

Components

Wiring / GPIO usage

  • GPIO 5: LED and crude CPU usage monitor
  • GPIO 21: LED Strip data connection
  • GPIO 16: I2C-SDA for ADXL345
  • GPIO 17: I2C-SCL for ADXL345

It is assumed (and recommended) that the LED Strip itself is externally powered, due to heavy peak current demands with some LED patterns.

Setup

Minimum Requirements

  • ESP-IDF installed correctly on the development system. This code was tested against the latest IDF as of end of December 2016. NOTE: The ESP-IDF is a rapidly moving target. Your mileage may vary.
  • FWIW, development for this project was performed using Mac OSX, and using Eclipse for editing
  • I used the ESP32 Thing's built in serial bootloader to download new application code builds using the IDF's "make flash" feature. For faster downloads, I highly suggest using "make menuconfig" to increase the bootloader's serial bit rate AND use compression.

Configuration

Accelerometer

  • Use "make menuconfig" to enable or disable the accelerometer option. See "Component Config -> EshThing" options.

Wifi and MQTT

  • The wifi setup may be updated via "make menuconfig". See "Component Config"->"EshThing" to update SSID and password.
  • The target MQTT server may be updated via "make menuconfig". See "Component Config"->"EshThing" to update the target MQTT server.
  • The MQTT clientID may be updated via "make menuconfig". See "Component Config"->"EshThing" to update the MQTT ClientId.

MQTT Topics

  • "/EshThings/Events/Pattern"
    • All builds subscribe to this topic. A simple string/number is expected:
    • '0' none. Pattern is off.
    • '1' Hann Window pulse. Single pulse and then off.
    • '2' Hann Window repeating pulse
    • '3' Random noise using ESP32 random generator source
    • '4' SOS Morse Code pattern pulse. Single pulse and then off.
    • '5' Same as '1', but scaled by 0.5
    • '6' Same as '2', but scaled by 0.5
    • '7' Knight Rider
  • "/EshThings/Events/Accelerometer"
    • Builds WITHOUT a physical accelerometer will subscribe to this topic. Any event will trigger LED behavior.
    • Builds WITH a physical accelerometer will publish to this topic when a threshold of accelerometer data is crossed. The published data includes the magnitude information.

Teaching Demo

The purpose of this repository is to present various FreeRTOS concepts at a microcontroller meetup in Nashville TN. The concepts and their locations:

  • Semaphores: led_strip (third party)
  • Mutex: led_strip (third party as modified by Matthew)
  • Queues: ColorMappedDataVisualizer (original to this code)
  • Timers: PatternGenerator (original to this code)
  • Polling Thread: AccelReader (original to this code)

Third Party

Third party code and modules required or included directly in this project:

Other resources:

Who do I talk to?