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AHT10 - I2C problem

msimon

I just bought AHT10 humidity and temperature sensor. I have seen that it supports I2C and it is cheap so I didn't think thoroughly and bought two. I wanted to try them then I encounter a problem that only a single AHT10 can be connected to single I2C bus. I thought it is related to static address but it is worse (breakout board also showing two address but no details in the datasheet). The datasheet says that "Only a single AHT10 can be connected to the I2C bus and no other I2C devices can be connected." It sounds like traditional serial communication like RS232 not I2C. 

Is it normal to advertise it as an I2C device? and I also wonder what is the technical issue preventing to connect other devices with different address. Did you have any experience similar to this on any other sensor?

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  • Just curious, what is the scenario where they will both be deployed connected to the same microcontroller?
    Ordinarily, the distance cannot be too great with I2C (i.e. i2C not normally used for local/remote sensing, unless remote is something inside the same enclosure (usually). Do you intend to have the sensors connected over a long distance?

  • in reply to shabaz

    I am planning to put one inside the hive the other outside the hive on the same microcontroller. I am thinking to put them roughly 10cm away from each other located on the top of the hive. However, the configuration may change as there are various thermal spots inside the hive. Actually, I may need more than two still researching characteristic of the hive temperature. 

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  • in reply to shabaz

    I am planning to put one inside the hive the other outside the hive on the same microcontroller. I am thinking to put them roughly 10cm away from each other located on the top of the hive. However, the configuration may change as there are various thermal spots inside the hive. Actually, I may need more than two still researching characteristic of the hive temperature. 

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  • in reply to msimon

    I see; in that case, perhaps something like this could be useful, it's a low-cost component (PCA9548A), called an I2C Multiplexer if you're looking for such types of parts. Then you're free to add quite a lot of sensors. 

    Personally I'd do it in software though (i.e. using GPIO pins) if there are enough pins. But this could be a scalable way for up to 8 devices (actually up to 64 devices, since you can install many of these PCA.. chips but that seems an unlikely scenario).

    image

  • in reply to shabaz

    Actually, there may be a translation error. It works with TMP102 sensor. I also think GPIO is a good option.

    I won't invest in a mux for these unreliable sensors. I just want to play with them and see how I can mitigate it. If things not sorted, I will buy a better sensor.