MAX31865 RTD to Digital Converter (pt100) - Home Brew Forums
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Old 12-08-2012, 12:34 AM   #1
Liquiddog
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I just ordered three of these chips. Anybody else interested in figuring out how to interface one with an Arduino? More to come.



 
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Old 12-08-2012, 01:24 AM   #2
Vesku
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Any particular reason that you want to use pt100 with the Arduino instead of the ds18b20? ds18b20's are very very good and easy to work with. All of mine have been super linear and they all give out the same reading -> no need to calibrate like the analog devices.

Keep us posted how it goes. I'm waiting for an AD620, so I can add scale(s) on my Arduino....



 
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Old 01-02-2013, 02:55 AM   #3
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Quote:
Originally Posted by Liquiddog View Post
I just ordered three of these chips. Anybody else interested in figuring out how to interface one with an Arduino? More to come.
They interface over SPI (Serial Peripheral Interface). I have done a ton of C code for SPI devices so I could help you with that but I've never used Arduino hardware or the wiring language.

They have a SPI library but as I said I've never used it. The Maxim device uses half-word (16 bit) transfers and I don't know if the library handles transfers that large...

- Matt.

 
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Old 01-10-2013, 08:24 AM   #4
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QFN package looks a bitch to solder

http://store.curiousinventor.com/gui..._Soldering/QFN

 
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Old 01-10-2013, 09:17 AM   #5
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Quote:
Originally Posted by alien View Post
QFN package looks a bitch to solder

http://store.curiousinventor.com/gui..._Soldering/QFN
Not too bad with the right stuff. Inspection scope, apply solder pasted with a pic, set part down. I'd run it in my toaster oven. Then touch up with an iron around the periphery.

I do them all the time this way. Freehand, without the scope, or with normal wick solder, might be dicey.
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Old 01-10-2013, 06:57 PM   #6
alien
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OK. And in the event of disaster one can just sample some more from Maxim

 
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Old 01-11-2013, 02:18 PM   #7
mattwood2000
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Quote:
Originally Posted by alien View Post
QFN package looks a bitch to solder

http://store.curiousinventor.com/gui..._Soldering/QFN
Toaster oven reflow works quite well with these...just need a little patience and a steady hand.

 
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Old 01-24-2013, 08:58 PM   #8
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I'm trying to do this exact thing but with PT1000. Have you had any luck?

 
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Old 01-25-2013, 01:12 AM   #9
alien
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This might help http://www.mouser.com/pdfdocs/Maxim-...asurements.pdf

Edit: in fact the MAX31865 data sheet says it can handle PT1000.

 
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Old 01-25-2013, 06:07 PM   #10
Liquiddog
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Quote:
Originally Posted by tjackson View Post
I'm trying to do this exact thing but with PT1000. Have you had any luck?
Haven't quite made it to this project. I'm planning to pick up a Schmart board this weekend to mount the chip. Not the cheapest route ($10 per chip) but looks like the easiest.


One of the above comments suggests the standard Arduino libraries may not support this chip's SPI interface which I'm also going to look at this weekend.



 
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