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; use
esptool.exe --port COM6 --chip esp32 erase_flash esptool.exe --port COM6 --chip esp32 write_flash -z 0x0 adafruit.......bin
Open the COM port in Putty, set the settings.toml file to allow WiFi, restart and connect over web interface.
Load in my program, setting up the Grove connector to be a UART.
Connect my GPS over Grove.
