Easy IoT is a simplest IoT Solution presented by DFRobot
Esepcially this one: https://www.dfrobot.com/wiki/index.php/ ... U:_DFR0492

Looks like the ATMega328P is ok, I can run programs (and blink led). Serial console sometimes work, sometimes COM port is not available. My phone (Samsung Galaxy A5 2016) could find the bluetooth device, but there was only one time when I saw bluetooth communication is working (on the serial console). I have installed BlunoBasicDemo and several other programs on android, but this device is not detected at all.
The AT+ commands work on the serial console - if the device is really reachable.
I have replaced the USB cable, the USB port, even Windows and Linux were tried. But the USB connection is not really reliable, BLE looks does not work at all (just one time it worked).
I have upgraded the firmware (to 1.1) but that did not help at all.

So what am I missing?
Hm. I now made a lot of different tests, I'm not really sure about the result.
1. I can upload sketch, which does not use bluetooth and worked perfectly. That is not an issue at all.
2. Yes, the port used was sometimes lost, sometimes changed and it happened both on linux and windows.
3. I have installed the BlunoBasicDemo apk, which sometimes found the device, sometimes not. I don't know how it was related to the OS I use (linux/windows) and the port.
4. if I try (another) app to connect to this device using bluetooth and the connection failed the device cannot be seen any more and even BlunoBasicDemo cannot connect to it. Reset, disconnect does not help, sometimes the reboot of the phone helped, but sometimes not.
5. The AT commands work, if port was set properly.
6. it looks like bluetooth works better if USB was not connected (Firebeetle works on battery).

So the main problem is the bluetooth communication between FireBeetle and my Android device is - how to say - occasional, unreliable.

I would like to get a "howto" or example or tutorial on how should I set it up, but it looks like the official documentation is insufficient. Or just I could not find it.