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  1. #1

    No idea what is on this board inside of a temp/humidity unit from store.

    I read the "read before you post" and I am new to this kind of thing, so I do not know if this is a micro-controller or not, please do not ban me if so.. I have googled this thing forever and still dont know what I am looking at.

    I have attached a pic, it was inside of a 10 dollar humidity temp detector at the store. I opened it to make sure it wasnt emitting EMF (the box said nothing about being wireless but I wanted to see for myself).

    I just want to know what these parts are, and if it has an antenna that it didnt want people to know about.

    I am sorry I am amateur at this, I spent an hour searching all the numbers on the board with no info gained and stopped after I got lost reading about analog off-board ferrite cages or something like that.. I have no clue about any of this stuff.

    thanks sirs.

    Click image for larger version. 

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  2. #2
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    Re: No idea what is on this board inside of a temp/humidity unit from store.

    As far as your concern, and upto my knowledge, there is no RF parts in this design.
    This circuit seems to be a cheap Chinese design, which uses...
    1. COB IC (Big black round dot) - for processing.
    2. A crystal oscillator (silver cylinder), to provide a clock frequency to COB IC.
    3. some kind of sensor (Leaded part on bottom left.)
    4. a Switch Input (PCB traces near C/F print) - (C/F seems to be Celsius / Fahrenheit)
    5. Few passive component. - to make circuit work.
    6. Red / Black wires for battery connection.


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    Re: No idea what is on this board inside of a temp/humidity unit from store.

    Hi,

    I agree with the above.

    A bit more detailed about the "COB":
    It is a silicon chip glued on the PCB (COB = Chip On Board)
    Very small bonding wires electrically connect the chip with the board.
    The black compound mainly protects the chip and the bonding wires from nechanical stress.

    The chip does:
    * the timing control
    * analog to digital conversion
    * data processing
    * charge pump (for display control)
    * display control

    The chip is the most complex part of this device. It may contain several thousand transistors
    ... although it may be in the size if 1mm x 1mm.

    Do an internet search for "chip on board" for more informations and pictures.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.


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    Re: No idea what is on this board inside of a temp/humidity unit from store.

    Click image for larger version. 

Name:	IMG_4642.jpg 
Views:	1 
Size:	141.1 KB 
ID:	155884

    I believe the component bottom left is a "resistive humidity sensor". Looks almost identical to this one.


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    Re: No idea what is on this board inside of a temp/humidity unit from store.

    Quote Originally Posted by ec_nisarg View Post
    As far as your concern, and upto my knowledge, there is no RF parts in this design.
    This circuit seems to be a cheap Chinese design, which uses...
    1. COB IC (Big black round dot) - for processing.
    2. A crystal oscillator (silver cylinder), to provide a clock frequency to COB IC.
    3. some kind of sensor (Leaded part on bottom left.)
    4. a Switch Input (PCB traces near C/F print) - (C/F seems to be Celsius / Fahrenheit)
    5. Few passive component. - to make circuit work.
    6. Red / Black wires for battery connection.
    Quote Originally Posted by KlausST View Post
    Hi,

    I agree with the above.

    A bit more detailed about the "COB":
    It is a silicon chip glued on the PCB (COB = Chip On Board)
    Very small bonding wires electrically connect the chip with the board.
    The black compound mainly protects the chip and the bonding wires from nechanical stress.

    The chip does:
    * the timing control
    * analog to digital conversion
    * data processing
    * charge pump (for display control)
    * display control

    The chip is the most complex part of this device. It may contain several thousand transistors
    ... although it may be in the size if 1mm x 1mm.

    Do an internet search for "chip on board" for more informations and pictures.

    Klaus
    Quote Originally Posted by Kajunbee View Post
    Click image for larger version. 

Name:	IMG_4642.jpg 
Views:	1 
Size:	141.1 KB 
ID:	155884

    I believe the component bottom left is a "resistive humidity sensor". Looks almost identical to this one.
    Well I am extremely impressed with the replies wow, thank you guys so very much.. honestly. I know its pretty lame to show up and "wtf is this circuit board!", but I am grateful you all took the time to help out and provide some real quality info. Couldnt have found it myself (i tried).

    Its just hard to trust these little electronics devices these days, even ones from major chain stores.. I even heard about walmart allowing all types of agreements with random gadget manufacturers to let them mine data on people, so I can never be too sure just what is inside these things.

    Thanks a bunch for the help.



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  6. #6
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    Re: No idea what is on this board inside of a temp/humidity unit from store.

    Hi,

    Its just hard to trust these little electronics devices these days,
    What´s the alternative: Human or horse hair? Can one trust them more than electronics?

    In either way: If you want reliable results you should look for certified humidity meters.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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