WizNet5100 ethernet module chip temperature

  • Hello!

    Maybe someone who uses W5100 based Ethernet module in MQTT gateway can tell how hot the chip in ethernet module is?

    Mine was (and still is) hot and accordingly to specs this kind of modules will consume typically 185mA (3,3V) in 100M connection what is a lot. But problem is that now gateway is not responding to openHAB and ping dont get answer.

    Gateway serial port only shows messages from radio network and no TCP debug information. Module have lights blinking and chip is hot but nothing happens. Is it so that W5100 burnt himself out? It worked continiously few weeks.

    But ENC based MQTT I didnt get to work and soft SPI version didnt fit into Nano memory. Probably I will test it with Mega and see if this combination will work. Does someone have ENC based MQTT gateway what is working?


  • Contest Winner


    yes, I had this problem and had to adjust the power supply... I had a 12V 1000mA, but knocked it down to 9V and it ran cool. I think my issue is poor quality wiznet board I bought. Anyway, it works fine for me now.

    you may not have fried the board... disconnect it and let it cool down, try again.

  • Thanx for your feedback!

    I have also 12V power adapter but it is connected to 5V switching regulator (5V linear regulator 7805 got too hot and heatsink took lots of space) and with this 5V I power Nano and ethernet module and for radio is separate 3,3V linear regulator powered from 12V.
    Everything is cool exept ethenet module chip and module 3,3V regulator.

    I waited a day but no communication between Nano and ethernet module (all lights are blinking) and no ping reply. I also uploaded simple web server sketch but web server also not working.

    First step is ordering one cheap w5100 module from China. And also check things with oscilloscope.

    Probably I must take a time and test ENC based ethernet module with Mega and softSPI. And if this combination not working or working but not reliable then old good serial port is last resort.
    But openHAB will not have serial binding for mysensors what mean that I have to look to another controller or make my own controller.


  • Contest Winner

    check out the cool controllers developed for raspberry pi... lots of good stuff happening here like PiDome.

    good luck with the next shield! (I have fried a couple myself)

  • Yep, I already looked too PiDome because it can be used with serial gateway. But using standard MQTT was very appealing.

    If not only me have fried w5100 boards then probably they are suitable only using as clients not servers. And they cannot connect to servers too often.


  • I use a cheap Chinese 5100 module together with the MQTT gateway and it is warm but have not measured any actual temperature. Works 24 hours a day (now for a couple of months). Most problems have been due to the MQTT code implementation itself . But for most "simple" sensors it runs OK with Openhab.

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