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.
- 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.
- Sparkfun ESP32 Thing
- Adafruit NeoPixel Digital RGB LED Strip - Black 60 LED
- Code as published assumes 60 LEDs per device, but is easy to change.
- ADXL345 Accelerometer
- Build supports with or without accelerometer, using "make menuconfig" to change.
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.
- 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.
- 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.
- 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
- 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.
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 code and modules required or included directly in this project: