I'd like to connect PT100 to the core

Hi,
I’d like to connect PT100 to the core, but how to connect?
Could you kindly give me advice?

PT100 thermocouple found in some 3D printers?

You need a bridge circuit in order or something similar made into a chip.

That’s what I learnt after tearing some machines apart :slight_smile:

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A quick search on google and ebay yielded NO good information on PT100. Please provide a specification sheet for the device you are trying to connect to the Spark Core and we can help point you in the right direction.

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Hi Daisuke,

Is there a particular reason you want to use the pt100 sensor? I tried connecting a pt100 to an Arduino for some brewing gear a couple of years back without much success. The pt100 requires some extra circuits to interface with the Arduino (and similar for the park core). I can’t remember the details, but i think it involved a voltage splitter as well as an amplifier. I struggled with noise in my circuit and gave up when I discovered that the DS18B20 sensor is much easier to use since it is digital. Have you tried this instead?

I bought it here

I’d like to send temperature info to my phone every hours.

Hi. I’d like to make the templature directing device can get official approval of the Japan Meteorological Agency. The approval requires devices has water proof and accuracy of temperatures. The devices is tested on environment of -50 to +50degree Celsius. The test request span of instrumental error should be below -0.3 to +0.3degree Celsius. That’s why I want to use Pt100.

More of the same, specs… but nothing to help you actually determine what it is, or how to hook it up.

- Color: White
- Material: Aluminum + plastic
- PT100 insulated probe
- Temperature: -20~500'C
- Cable length: 1.77 meter
- Widely used in science and industry applications including temperature measurement for kilns,
gas turbine exhaust, diesel engines, and other industrial processes

Dimensions: 9.45 in x 0.59 in x 0.59 in (24.0 cm x 1.5 cm x 1.5 cm)
Weight: 3.88 oz (110 g)

One of the reviews suggests it’s a Thermistor, not a Thermocouple. Either way we are just throwing darts at the wall and won’t be able to REALLY help you. There are ways to characterize this yourself if it’s a NTC Thermistor. I would suggest reading this whole thread :slight_smile: https://community.spark.io/t/thermistors-and-the-spark-core/1276

If you need that kind of accuracy, I would buy a K type thermocouple probe and connect it to a Fluke 179 multimeter. Even then I wouldn’t consider it more accurate than +/- 0.5°C

Hi @Daisuke

I think you might want to read this app note from Maxim:

http://www.maximintegrated.com/app-notes/index.mvp/id/3450

One of the challenges with getting really accurate measurements from RTD/thermocouples (assuming what you bought is really a platinum rtd) is that you need to use 3- or even better 4-wire connections (Kelvin connection) to isolate the current carrying wires from the sensing wires. Another challenge is that the most accurate way to connect one is with a wheatstone bridge. These two things mean that you will need external components since the core’s analog ground is the same as the digital ground for the power supply,

Figure 9 in the app note shows a way that would work well with core, using 3v3* as the reference voltage:

http://www.maximintegrated.com/images/appnotes/3450/3450Fig09.gif

Hmm, so I’ll admit I’ve never used a Platinum RTD before… I guess it’s more accurate but slower than a thermocouple:

Cheap thermocouple amps:

With SPI to take the error out of the A/D conversion that you’ll likely experience somewhat:

Or maybe +/-0.5°C DS18B20 is the way to go:

Hmm, so I’ll admit I’ve never used a Platinum RTD before… I guess it’s more accurate but slower than a thermocouple:

Cheap thermocouple amps:

With SPI to take the error out of the A/D conversion that you’ll likely experience somewhat:

Or maybe +/-0.5°C DS18B20 is the way to go: