My Arduino UNO is up and running, but no mqtt messages


I don’t have anything connected to my Arduino UNO apart from recover and transmitter.
I built the project a month ago so don’t have the results, but there’s nothing wrong with it.
From memory, it was unstable when I went down to 128 so I decided to stick with 256…


Are you now connected to D3 or D2? (nothing to RX)


It’s all as per Wiki - pins 3 and 4.


If you plug the usb cable at start could you post what OMG shows on serial monitor?


Well, I normally power up my Arduino via the round power connector.
When I disconnect it from mains power adapter and connect to my PC with a USB cable, it starts just fine, here is the opuput in Serial Monitor:
Simple ethernet config
OpenMQTTGateway ip:
Ethernet ok
Connecting to MQTT by IP adress
ZgatewayRF setup done
Setup OpenMQTTGateway end
MQTT connection…
Connected to broker
Subscription OK to the subjects

I tried to power it up via USB cable (using a 5V phone charger with a USB socket), but it doesn’t make any difference to the original situation - it hangs until I press reset button on it.

I suspect that Arduino receives something via USB that makes it boot when connected to PC.
Any idea how to overcome it?


What is the measured voltage on this plug?


It’s 9V. (stupid min 20 characters rule)


Could you post a photo of your setup (not with usb but the board wired with the power connector)?


there is no difference to this picture, I just plug a power adapter into the slot.
And as I said, it works the same if I power it up via USB port.


It seems that you have data connected to TX on this picture and not to D3 as it should




Did you try with some basic blink sketch if you have the same behaviour (also with w5100 connected)?


No I didn’t.
What should I upload?
I presume it needs some basic configuration as well?


Not, just upload a basic blink example provided with the ide, add the w5100, connect a led with a resistor and see if you reproduce the same behaviour


Any instructions on what pins to connect a led to?


Ok, can’t try anything because I tried to upload the latest 0.9beta to my Arduino UNO, but forgot to disconnect the Ethernet shield. When I tried to upload, it shows:
vrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00

Disconnected the shield, even tried a different UNO - same errors.
Installed Arduino IDE on a Windows machine, same errors.
Tried to upload a Blink program through platformio, same errors on both boards.
Tried a different USB cable.
Loop test doesn’t seem to work.

The worst thing is that the OMG that was working now does not work when I connect it back (it blinks its LEDs on the Ethernet shield, but I can see no mqtt messages from OMG at all). It shows nothing in Serial Monitor in Arduino IDE.

How 2 boards could die simultaneously? Have you ever heard about something like that?


Are you sure of your board parameters (from arduino tools menu)?


Well, I selected Arduino UNO. Last time I uploaded even with Arduino Ethernet or Arduino WiFi, and it worked fine…


If I understand well now this is working?


No, it isn’t. I mean that Board type I select is Arduino UNO so there is no error.
Just wanted to say that previously when I payed with it, it was possible to select Arduino Ethernet or Ardiono WiFi and upload went ok as far as I remember.