DHT22 communication isolation

Using Arduino Sensors
1

Hello person, is there any way to galvanically isolate the arduino communication with the DHT22 sensor using optocouplers?, I know it works in 2-way communication like TX and RX.

2

Nope! You will need supporting electronics on each side of the communication link. Look at your example and Check how they are supporting it, there is electronics to do that.

3

Welcome back.

Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project :wink: See About the Installation & Troubleshooting category.

4

Hi, @heinsschonhals

Can you describe your project and why you need galvanic isolation?
How far between the sensor and the controller?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

5

hi, @TomGeorge ,
I'm designing a board that uses the atmega2560, to which I'm making a robust board for use in more "hostile" environments, so all inputs, and outputs, both analog and digital, I'm galvanically isolating with optocouplers, some sensors like the hc -sr04 also works with this isolation, but as the DHT22 has one-wire communication I haven't found this possibility yet, I tested it with two optocouplers, one for each side but it didn't work! Oh, I'm stuck on this one.

6

Hi,
You may have to change your sensor to one that uses I2C and use an I2C isolator IC.

Google;

i2c isolator ic

Tom... :smiley: :+1: :coffee: :australia:

7

because it is an alternative, but it can limit the distance a little

8

Hi,
Yes, I2C has its limits on distance.
The other method would be, but it would be costly, use analog output devices and get industrial grade analog isolators.

They are used at my workplace for projects, but not cheap.

I'm not sure what these companies use.

https://www.controllino.com/

Tom... :smiley: :+1: :coffee: :australia:

9

The advantage of the DHT22 is to offer temperature and humidity, I think the best way is still to use an analog sensor for each one, because the analog inputs have already been isolated with the optocouplers.

10

Hi,

What opto couplers are you using, most are only digital ON/OFF, there are linear analog types.

Tom... :smiley: :+1: :coffee: :australia:
PS:I'm off to bed, 2:15am here, g'dnight mate... :sleeping: :sleeping: :sleeping: :sleeping:

11

fiz um circuito com amplificador operacional e utilizando 2 optoacopladores pc817, ja testei na pratica e funciona bem

12

Hi,

Great stuff. :+1: :+1: :+1:

Tom... :smiley: :+1: :coffee: :australia:

13

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