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MAX31855 only reads when I touch board
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MAX31855 only reads when I touch board

by jamesgame66 on Sat Nov 21, 2020 8:11 am

Using the sample serialthermocouple code and a K type sensor (I've tried at least 4) I cannot get a constant reading of the internal and thermocouple temperature unless I hold the MAX31855 board between my thumb and forefinger and they are in contact with the components on the attached photo.
IMG_20201121_115810.jpg
IMG_20201121_115810.jpg (297.04 KiB) Viewed 30 times


Excuse my lack of intimate knowledge of electronics but it seems that I am shorting or somehow affecting one or more of these components through my skin. I have tried two different MAX31855 boards and had exactly the same behaviour.

To be clear, if I dont touch the board then all measurements are reported as 0.00 but when I touch and hold the board then I get something close to the correct thermocouple temperature,

jamesgame66
 
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Re: MAX31855 only reads when I touch board

by adafruit_support_bill on Sat Nov 21, 2020 12:03 pm

Please post photos showing all of your soldering and connections to the board.

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Re: MAX31855 only reads when I touch board

by jamesgame66 on Sat Nov 21, 2020 12:41 pm

Here are the connections
Attachments
IMG_20201121_162603_1.jpg
IMG_20201121_162603_1.jpg (202.97 KiB) Viewed 25 times
IMG_20201121_162613.jpg
IMG_20201121_162613.jpg (271.2 KiB) Viewed 25 times
IMG_20201121_162556.jpg
IMG_20201121_162556.jpg (258.23 KiB) Viewed 25 times

jamesgame66
 
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Re: MAX31855 only reads when I touch board

by adafruit_support_bill on Sat Nov 21, 2020 2:14 pm

Please post some photos showing your soldering on the board.

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Re: MAX31855 only reads when I touch board

by jamesgame66 on Sat Nov 21, 2020 2:29 pm

I havent carried out any soldering on the MAX31855 if that is what you mean

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Re: MAX31855 only reads when I touch board

by adafruit_support_bill on Sat Nov 21, 2020 3:36 pm

If you did not solder the headers to the board then it will not work reliably.

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Re: MAX31855 only reads when I touch board

by jamesgame66 on Sat Nov 21, 2020 5:01 pm

The headers are pre-soldered to the board as per this photograph
Attachments
IMG_20201121_205832.jpg
IMG_20201121_205832.jpg (263.28 KiB) Viewed 16 times

jamesgame66
 
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Re: MAX31855 only reads when I touch board

by adafruit_support_bill on Sat Nov 21, 2020 11:00 pm

That is not an Adafruit board. You should contact the seller of the board for technical assistance.

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Please be positive and constructive with your questions and comments.