IoT for entrepreneurs: faq
1. The screen shows a lot of white particles
2. "DynamicJsonBuffer not declared in this scope"
This error appears when you compile the sketch, you can not download the sketch to the board.
Solution: you installed a version of the library ArduinoJson which is too recent and not stable
close your Arduino IDE.
Uninstall the ArduinoJson library by following these steps.
Install the correct version of the ArduinoJson library, which should be annotated as stable. As of September 2018, the latest stable version is 5.13.2. To find this version, go to Sketch → Include Library → Manage Libraries. Type "ArduinoJson" in the search bar. Before installing it, make sure to select version 5.13.2 in the drop down menu!
Relaunch the Arduino IDE to make sure the changes take effect.
3. "fatal error: Adafruit_SSD1306.h: No such file or directory"
install the library from Sketch → Include Library → Manage Libraries: type SSD1306 in the search bar and find it.
|In the list of SSD1306 Libraries, make sure you install the one by Adafruit, not Acrobotic.|
Import this lirary in your sketch via Sketch → Include Libraries → find it in the list!!
4. "cannot access COM1 / espcomm_open failed"
if you are on a Mac:
New / recent Mac only: make sure you installed this:
Older Mac (Mac OS 10.12.6 or older): make sure you installed this instead:
All Macs: in the Arduino IDE, with your sketch open, go to
Toolsand put your mouse above (don’t click!)
Port:. Then select:
→ In the list of ports, select the one that has "/dev/cu.SLAB_USBtoUART" in the name
if you are on a PC:
→ In the list of ports, try selecting each port (COM1, COM17… you might have different ones) until the error disappears.
5. Upload complete but nothing on screen
the wifi ssid is invalid: the name of the ssid you are using includes spaces or special characters (like: "my super wifi")*
→ Use a wifi ssid and passwords which are simpler (like: "mysuperwifi")
If you are on a Mac Computer, the adaptator for USB cables (white cable on the picture below) does not work:
→ try changing the usb cable. Some cables don’t work.