EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: S. Petrukhin on June 06, 2023, 01:58:46 pm
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Hi, friends!
Please help me understand the humidity sensor SHT30-ARD.
Sensirion does not have such a sensor or it is very old. Perhaps this is some kind of Chinese version.
This sensor is not a SHT30-DIS (have't I2C) and not a SHT30-ARP (have't analog output).
When power is applied to it, a short pulse passes to pin 1 and then a sequence of 5.4 seconds duration out to pin 4.
What is it and how to decode it?
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For starters, what indication do you have that such a chip exists? :-//
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For starters, what indication do you have that such a chip exists? :-//
It's on my desk and works in someone else's system. :)
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For starters, what indication do you have that such a chip exists? :-//
It's on my desk and works in someone else's system. :)
I guess I was curious about the exact lettering on the chip, and what the package looks like. ;)
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For starters, what indication do you have that such a chip exists? :-//
It's on my desk and works in someone else's system. :)
I guess I was curious about the exact lettering on the chip, and what the package looks like. ;)
The appearance of a regular ST30.
The connection is very similar to the SHT30-ARP, but it outputs a digital signal.
Inscription:
SHT30
ARD33P
I can take a photo only tomorrow...
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Is the pulse repeating or only occurs once on startup? If it repeats could be a PWM representation of T and RH.
What is connected on pin 1 and 4 in their system, any capacitors, resistors, etc.?
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Is the pulse repeating or only occurs once on startup? If it repeats could be a PWM representation of T and RH.
What is connected on pin 1 and 4 in their system, any capacitors, resistors, etc.?
It doesn't look like PWM or SDM, there is no smooth signal of some duty cycle, there is a stream of random bits.
The circuit is unknown on the receiving side, both outputs are 10nF capacitors near the sensor.
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Is the pulse repeating or only occurs once on startup? If it repeats could be a PWM representation of T and RH.
What is connected on pin 1 and 4 in their system, any capacitors, resistors, etc.?
It doesn't look like PWM or SDM, there is no smooth signal of some duty cycle, there is a stream of random bits.
The circuit is unknown on the receiving side, both outputs are 10nF capacitors near the sensor.
To me it wouldn't make sense to have a 10nF capacitor on a data line. That is the recommended circuit for SHT30-ARP analog output version.
Maybe the analog output circuitry has been damaged.
"The first two digits XY (=AR) describe the output mode. The third letter (A) represents the manufacturing year (4 = 2014, 5 = 2015, etc). The last three digits (BCD) represent an
alphanumeric tracking code. That code can be decoded by Sensirion only and allows for tracking on batch level through production, calibration and testing – and will be provided upon justified request."
The part number you gave is for SHT30-ARP.
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To me it wouldn't make sense to have a 10nF capacitor on a data line. That is the recommended circuit for SHT30-ARP analog output version.
Maybe the analog output circuitry has been damaged.
"The first two digits XY (=AR) describe the output mode. The third letter (A) represents the manufacturing year (4 = 2014, 5 = 2015, etc). The last three digits (BCD) represent an
alphanumeric tracking code. That code can be decoded by Sensirion only and allows for tracking on batch level through production, calibration and testing – and will be provided upon justified request."
The part number you gave is for SHT30-ARP.
Yes, I know, I have studied the documentation.
This is probably a sensor from another manufacturer.
I remember a time when real I2C or full I2C was written in the description of sensors, therefore, before that or sensors with some incomplete I2C. I think it's just him, but I can't find a description for that incomplete I2C.
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Why would another manufacturer use the exact same marking as Sensiron but have different functionality? Doesn't make sense.
If the lines are I2C they wouldn't have capacitors, they'd have pullup resistors.
You can buy a clone of SHT30-D but its marked as "GX HT30": https://www.micros.com.pl/mediaserver/CZ_SHT30_GX_0001.pdf (https://www.micros.com.pl/mediaserver/CZ_SHT30_GX_0001.pdf)
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Dear friends!
This, however, turned out to be an analog sensor. A strange sequence of bits not similar to PWM or FM transmits exactly the voltage that should be integrated on the capacitor.
I was confused by the fact that there is no capacitor and resistor in someone else's circuit, the signal goes directly to the MC pin.
There are probably some algorithms for software integration of this signal.
Thank you for your participation and help!