1 DHT22 sensor on 2 Arduino uno boards

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1

Hi,
I want to use one DHT22 sensor for two Arduino uno boards.
One board is will use to display temperature with seven segment LED display and the other board is to display humidity at the same time.
Is there a way to do this with one sensor?
Thanks for the help!
Guido van Laere

2

It would be rather silly to use two "UNO" boards.

Just use one (and a Nano is better than a UNO for any practical application). Problem solved. :grinning:

3

Why two boards? The workload you mentioned is not much for a single board.

If it must be two...easiest will be to connect them with Serial, so one board reads the DHT22 and then transfers the reading to the other.

4

Thanks for your answer, but I'm a beginner with Arduino, so sorry for my questions....

I understand that I connect the DHT22 to the first Nano board en give this signal to a second Uno board.
So I need to make one pin of the first board output of the DHT22 and connect it with the second board?

I know how to have serial communication via an USB port to your computer, but I need to make one port available for serial communication. Can you give a direction where to find an example for this? I don't understand how to program this.

Thanks for your help,
Guido

5

Why are you even trying to use two boards?

Serial Input Basics and SoftwareSerial is what you need to know for starters. If you want to know more about the TTL Serial protocol adn how it works, start here.

6

Paul__B:
It would be rather silly to use two "UNO" boards.

wvmarle:
Why two boards? The workload you mentioned is not much for a single board.

wvmarle:
Why are you even trying to use two boards?

Are you getting the message here?

7

Hi,
Welcome back to the forum.

Please read http://forum.arduino.cc/index.php/topic,148850.0.html.

Thanks.. Tom... :slight_smile:
PS. Why two Nanos?

8

TomGeorge:
PS. Why two Nanos?

Heh, heh. :grinning:

9

Paul__B:
Heh, heh. :grinning:

Dear Paul,
I'm a beginner and have been able to make a working temperature and humidity meter with great difficulty. The temperature is now displayed every 5 seconds, followed by the humidity. Now I want to use 2 displays (TM1637). I have now received 2x a Nano boards and want to control this with 1 sensor.
Of course it will be possible to combine everything on one board and with a sensor. But I might want to try that in a next step.
Guido

10

Nanos are certainly the better choice.

There is no problem at all driving two TM1637 displays from one board, you just use two instances of the call to the library. Unlike using I2C, you do need to use a different two pins for each of the two displays but unless there is something you have not described yet, you have plenty of pins available.

So you need to combine the code for the two different display functions. That is not particularly difficult, you need to post your two codes here according to the instructions and we can work through it with you.

The idea of using two Arduinos and then having to formulate a complete communications protocol between the two would actually make the problem considerably more difficult as you would still be connecting the DHT22 sensor to one and reading and parsing both parameters from it, just as you would if you connect both displays to that one. And you cannot sensibly "share" this particular sort of sensor between two devices.

11

Unless you want those two displays to be so far from one another that wiring becomes impractical, using a single board is indeed going to be the easy way.

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