Because I was not satisfied with the information about the water temperature of the Baltic Sea during a past vacation stay, I built a thermometer with M5Stack components and a remote temperature sensor and presented it in a blog post. With the remote DS18B20 temperature sensor, I measured the water temperature at a depth of one meter.

Now the vacations are approaching again, and the message from the BSH still shows very cool water at the end of May.

I have extended the presented thermometer to follow the water temperature changes and be immune from bigger surprises.
Because of the slightly larger display, I replaced the M5StickC with an M5StickC+ and used an M5StickC 18650C to increase the battery capacity. In addition, the thermometer is much easier to handle.

To have the readings available on my mobile phone, I use it as a mobile hotspot and send the readings from the M5StickC+ via WiFi to the mobile phone, which then sends the data to the Pushover server. From there, the data is then distributed to the selected end devices.

This setup won't affect the water temperature, but I can record it in writing. And if it stays that cold, then I can document my heroism.

The link to the original post in German is https://wordpress.com/post/ckblog2016.net/4227

There is no serial response from this unit. No answer to AT @ 115200. Any idea?

Please have a look to my blog https://ckblog2016.net/2018/03/03/esp32-adc-dac/. Sorry for German language.

Hi @felmue
It was a good idea to replace the PIR by a wire. I have tried that w/o success.
I have prepared a Vbat measuring to see if battery is ok when USB is disconnected.
The CoreInk had now 3588 loops w/o USB connected. The battery goes from 4.1 V to 3.721 V after all these cycles (one second each). The battery is ok.
Thanks again.
Claus

@felmue said in M5CoreInk wake up by EXT0 (PIR Hat):

gpio_hold_en(GPIO_NUM_12); // POWER_HOLD_PIN
gpio_deep_sleep_hold_en();

Hi Felix

This are the last commands in my setup() now - but w/o success:

  esp_sleep_enable_ext0_wakeup(GPIO_NUM_36,1); //1 = High, 0 = Low

  //Go to sleep now
  if (DEBUG) 
  {
    Serial.println("Going to sleep now");
    Serial.flush();
  }
  delay(2000);
  gpio_hold_en(GPIO_NUM_12); // POWER_HOLD_PIN
  gpio_deep_sleep_hold_en();
  esp_deep_sleep_start();

I want to wake up an M5CoreInk by EXT0 (PIR Hat).
If I connect USB counting works. If I disconnect the USB cable the display loses its contrast and the software crashes.
I have no idea what's wrong. A program with wakeup by timer works.
The source is saved at https://github.com/ckuehnel/Arduino2020/tree/master/M5Stack/CoreInk_PIR.
Any hint is welcome.
best regards, Claus

@m5stack It works now as expected.

I tried the example for MQTT Unit and it works on Public Broker of Hivemq.com. But, I can see messages with a distance of one minute. In the serial output of the M5Atom I used, I can see the following in the meantime.
...
MQTT disconnected
MQTT disconnected
+MQUNCONNECT
+MQCONNECT
MQTT disconnected
MQTT disconnected
MQTT disconnected
MQTT disconnected
MQTT disconnected
+MQCONNECT
+MQUNCONNECT
MQTT disconnected
MQTT disconnected
MQTT disconnected
...
What is responsible for the disconnection?
How can I sent MQTT messages in a ten seconds cycle, for example?

I bought this unit but had no success configuring the device.
Scanning with an I2C scanner result in an I2C address 0x35. The microchip standard is 0x60.
Are there examples for M5Stick or Seeeduino XIAO?

@felmue said in Core2 PortC not working:

GPSRaw.begin(9600, SERIAL_8N1, 13, 14);// GPS init

Hi @felmue

Thanks a lot. It works. I small hint in the documentation would be nice.

Ciao Claus