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I plan on purchasing a Nano clone, an Ethernet shield (ENC28J60), an LCD and a DHT22 humidity + temperature sensor. This will be used in a wine cellar to monitor relative humidity and temperature.

The DHT sensor, LCD and Nano all operate on 5V logic. The Ethernet shield does not operate at 5V, but rather at 3.3V.

Does the Nano have a way to connect the two, will they work anyway (probably not), or should I use a CD4050 that is recommended on adafruit?

Any guidance is appreciated; I'm still amazed in what $10 in parts can do.

Also, in regards to the DHT22 sensor, what do I need in terms of a resistor? I've seen some people say you absolutely need a 4.7K resistor on the data pin for "pull up", and others who say it's unnecessary. Can someone give a definite answer, either way?

Edit, wrong link on my nano clone.

  • Could you provide links to something else than ebay? FYI, the second link is blocked in some countries, making it impossible to see what you're talking about. – jfpoilpret Nov 8 '14 at 6:30
  • Also is that a shield or a breakout board? – jfpoilpret Nov 8 '14 at 6:32
  • I believe it's a shield. Sorry, didn't know ebay was blocked for anyone. – Ethan Nov 8 '14 at 17:10
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Just get one with a 3.3v regulator on it. PS logic levels are allowed to be 5v.

DHT22 and LCD will also work fine on 3.3v so, alternatively, you could also get a 3.3v Nano.

The resistor value for the DHT22 depends on the length of wire between the DHT and Nano. Just buy them to be sure, or get a breakout board that already has them on the board (along with a capacitor, which is nice).

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