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Newbie in Arduino and MQTT project-Need help

Former Member

Hi,

I am a newbie in Arduino and MQTT projects..I want to use Temperature sensor as MQTT client by connecting it with Arduino UNO and Ethernet Shield.

I want to buy the required components.Kindly let me know whether the below are the correct components for this...

 

Arduino UNO-Are the both same product?If no,which one is the best to buy?

1)https://www.sparkfun.com/products/11021

2)http://www.simplelabs.co.in/content/arduino-uno

 

Ethernet shield-Are the both same product?If no,which one is the best to buy?

1) http://www.ebay.in/itm/Ethernet-Shield-W5100-for-arduino-UNO-Mega-/141511630995?_trksid=p2054897.l4275

2)https://www.sparkfun.com/products/9026?

 

Hope I have to  buy RJ45 cable?

One more wire seems to be connected from the Arduino board with computer USB port as per the video "https://www.youtube.com/watch?v=xj6eA8BIvlQ".Not sure what is the use of it..Kindly explain me..

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  • in reply to Former Member

    1) If the modem is a cable modem with an RJ45, yes you can connect with it. If it has more than 1 RJ45, then it will act as a router as well. Please tell what type of modem to confirm.

    2) Yes that is the minimum current. Did you see:

    Current rating: Since you'll probably be connecting other things to the Arduino (LEDs, LCDs, servos) you should get an adapter that can supply at least 500mA, or even 1000 mA (1 ampère). That way you can be sure you have enough juice to make each component of the circuit function reliably.

    You may need a bit more for the Ethernet shield...

     

    Cheers,

    Clem

  • in reply to Former Member

    Clem,

              pretty well answered your questions and more current capacity is useful at times.  The other thing to watch is that the power supply you buy is 9-12 volt DC output, excessive input voltage is inefficient and can cause the regulator to run hot.  The other point to note is that if you do use accessories that draw a lot of current, powerful servo's, motors etc.  then it is better to power these from an independent supply rather than from the Arduino pins.  You also have to keep in mind that the Arduino UNO 328 package has an overall current limit of 200 mA for all pins combined, and a limit for any individual pin of 40 mA.  The 3.3 volt output pin can only supply 50 mA to external circuits.  Thus if you are only running the UNO and the attached device do not exceed 200 mA then the 250 Ma supply is adequate.

     

    good luck

    Bob

  • in reply to clem57

    Hi Clem,

    I have Wireless ADSL 2+ Router..I just noticed that I have modem which also acting as Router only at home.Thanks for clearing this query for me. image