M5StickC

M5StickC orange and wearable. I have a few of these because they are cheap, come with lots of sensors, a tiny 80x160 LCD, and are nicely enclosed in a little case.

It uses an ESP32-PICO processor with 520KB of RAM and 4MB of FLASH. It's supposed to be a wearable so it has a battery. This MCU uses more power than an ESP32S3 if that matters to you.

Initially I set up one with a PIR hat and used it to control a light for about a year. Currently it's offline due to household politics. It works really perfectly for this with an MQTT connection to Home Assistant.

• What can I do with the internal temp sensor? There are sensors in both the PMIC and the MEMS sensors
• What can I do with its RTC? Datasheet https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/docs/datasheet/Stamp/StampTimerPower/RTC8563.pdf
• What can I do with the accel/gyro? Detect vibration or change of direction in a car? Step count? It supports "wake on motion". You can find its orientation by reading the accelerometer. "Down" is usually Z=1g for example.
• What can I do with the mic? Make lights blink? https://www.hackster.io/esikora/audio-visualization-with-esp32-i2s-mic-and-rgb-led-strip-4a251c
• Can I turn off TV's with the IR LED? https://www.hackster.io/alessandro-polselli/turn-m5stickc-into-universal-ir-remote-home-automation-d3ec0d

Internal photos (This "plus" version has bigger screen) https://www.gwendesign.ch/kb/m5stack/m5stickcplus/ and https://www.gwendesign.ch/kb/m5stack/m5stickc/

It has some magnets in it so you can stick it to things! Cool.

Batteries - it has an RTC button cell and a tiny (95mAH) LiPo. More of a UPS than a power supply.

Looks like taking it apart is a waste of time, things are pretty packed in there. Don't bother. Have lots of other ESP32 things already.

Development environment

So far I have tried ESPHome, CircuitPython and UIFlow on it so far. I have no interest in UIFlow, but I think since it runs on MicroPython you can ignore "flows" and load code.

Since this board has only 520KB of RAM I will probably not go much further with MicroPython and just break down and use C. ESPHome worked fine for my PIR sensor / MQTT IoT project, that's an option still for C programming.

Peripherals

Grove port GND 5V G32 G33 from the datasheet : GPIO32, ADC1_CH4, TOUCH9, RTC_GPIO9 GPIO33,

ADC1_CH5, TOUCH8, RTC_GPIO8

LCD display

6-axis IMU

PMIC

MIC

RTC

IR LED G9

Red LED G10

Button1 = Power on / off / reset

Button2 = G37

Button3 = G39

Pin header (used for add-ons such as the PIR Hat) -- GND 5VOUT G26 G36 G0 BAT 3V3 5VIN

GPIO26, DAC_2, ADC2_CH9, RTC_GPIO7, EMAC_RXD1

SENSOR_VP 5 I GPIO36, ADC1_CH0, RTC_GPIO0

GPIO0, ADC2_CH1, TOUCH1, RTC_GPIO11, CLK_OUT1, EMAC_TX_CL

Temperature

Projects

Motion sensor -- ESPhome + PIR Hat + a spare phone charger = a cheap motion sensor that reports over WiFi + MQTT.

LED strip controller -- working on this soon, to control RGBW strips over WiFi, or maybe I will press on with the Nordic nRF52840's and Zigbee.

CircuitPython

All the same things, but now in Python. That's the goal.

Download it from Circuit Python site

Install it

Load in my program, setting up the Grove connector to be a UART.

Connect my GPS over Grove.

Resources

https://docs.m5stack.com/en/core/m5stickc

https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/docs/datasheet/core/esp32-pico-d4_datasheet_en.pdf

Micropython

UIFlow guidebook