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3. Troubleshooting

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Ioannis Charalampidis edited this page Jan 23, 2019 · 4 revisions

3.1. Compile error "undefined reference to `uNode’”

Your compiler cannot link against the uNode library. Try the following:

  1. Make sure that your Arduino IDE is at version 1.8.6 or later
  2. Try re-installing the uNode library:
  3. Close your Arduino IDE
  4. Open your Documents / Arduino / libraries folder
  5. Delete the uNode folder
  6. Re-install the library from the zip file

3.2. java.io.IOException: Cannot run program "python.exe": …

Arduino cannot find your python installation.

  1. Make sure that you have python 2.7 installed (python 3.x is not supporteed)
  2. Make sure that python exists in your system path (windows instructions can be found here)

3.3. I triple click my RESET button but the Access Point never appears

If you are powering your device with batteries, make sure that you have enough voltage. You need at least 3.4V as your input voltage in order for the WiFi to operate normally.

Alternatively, try reseting the device once, wait 10 seconds and then triple-reset again.

3.4. When I connect D0 to GND the device does not boot

Due to the limited number of GPIOs available, we are using the GPIO2 as our D0. Unfortunately, GPIO2 also controls the boot mode of the device. If you have connected D0 directly to the ground, you have most probably selected an invalid boot mode and your device will never boot.

To mitigate this problem, try using the DTR pin as your GND, as shown on the schematic below:

This pin is not connected while the device is booting and will allow it to start without any problem. When the sketch is started, it will be pulled LOW, and therefore it will behave like a GND.

3.5. I am unable to program the μNode using an FTDI adapter

  1. If you are powering the board from the FTDI adapter, make sure it can provide enough current. Some cheap FTDI adapters have a very small regulator for 3.3v and it does not provide enough current for ESP to work.

  2. Make sure that your FTDI adapter’s RTS pin is connected to the RTS pin on the board. A typical 6-pin FTDI adapter does not include the RTS pin on the header, but on the sides.

  3. If it still doesn’t work, make sure that you have selected “dtrset” reset method from the Arduino “Tools” menu.

  4. If you still have issues, it could be that the FTDI adapter does not properly control the DTR pin. You can try the following:

    1. Connect the DTR pin to GND
    2. Press once the RESET button
    3. Without powering off the device, plug in you FTDI adapter and press Upload.

3.6. I see garbage on the Serial Monitor

There are two kinds of messages sent on the serial monitor and both of them are using different settings. Make sure that your baud rate is set correctly depending on the messages that you want to see:

  • For ESP8266 boot messages, the baud rate should be 74880.
    
Use this baud rate to debug boot issues (ex. booting on the wrong mode), or to get stack traces in case of a critical exception.

  • For normal operation messages, the baud rate should be 115200.
    Use this baud rate to monitor the device actions (ex. when it powers up/down the peripherals, when it’s transmitting messages etc.)

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