I2C multiple same sensors (SI7021)

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hasanpb
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I2C multiple same sensors (SI7021)

#1 Post by hasanpb » 07 Sep 2017, 18:14

Hi,
I would like to ask you, if it is possible to connect more than one of same sensor (SI7021) on one I2C bus on ESPEASY.

Thanks
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toffel969
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Re: I2C multiple same sensors (SI7021)

#2 Post by toffel969 » 07 Sep 2017, 19:04

hasanpb wrote: ↑07 Sep 2017, 18:14 Hi,
I would like to ask you, if it is possible to connect more than one of same sensor (SI7021) on one I2C bus on ESPEASY.

Thanks
No you cannot connect two i2c with same adress
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hasanpb
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Re: I2C multiple same sensors (SI7021)

#3 Post by hasanpb » 07 Sep 2017, 21:19

Ok. Thanks for answer.
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papperone
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Re: I2C multiple same sensors (SI7021)

#4 Post by papperone » 07 Sep 2017, 23:10

Yes, you can do it of course! using a (still!) not supported I2C expander named TCA9548A.
There were some discussion on how to implement it in ESPEasy but due to the not easy intergation with current I2C handler it was decided to park it for release 2.1
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Shardan
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Re: I2C multiple same sensors (SI7021)

#5 Post by Shardan » 08 Sep 2017, 15:04

as i2c is of limited lenght you would be able to place
two si7021 on a distance of about 1 m reliably.
How much sense would that make?

Basically it is possible to use i2c expander to extend the length.
Expander and a doubler chip might work ... i'd prefer a second esp in that case.

It usually gets out of mind that i2c was devsloped as an in-box bus system
for tv sets, cd players and such.

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Shardan
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