Thermocouple

Hello, I need help with connecting Thermocouple to my Arduino. I use a Arduino micro and the following K-type thermocouple:

https://www.aliexpress.com/item/New-K-Type-Thermocouple-Temperature-Sensor-92CM-Wire-Thermocouple-Probe-20-300C/32832656978.html

I'm really new at Arduino and I'm not sure whether I need an adapter or how to connect my thermocouple to Arduino. I saw that there are several libraries ready but not for this specific thermocouple, I'm just trying to understand how the connection itself is done and monitoring the information.

Thanks you very much!

The thermocouple puts out a very small amount of voltage. You need an additional component between the thermocouple and the Arduino to amplify the signal to something your Arduino can read. For this purpose I use one of the MAX31855K modules. Another option is the MAX6675, which has a smaller range of temperatures it can measure and is probably costs a bit less. You will find Arduino libraries for either of those chips.

thanks you very much!

If I'm connecting a few thermocouples at the same time, do I need a few amplifiers?

I believe there are multi-channel thermocouple amplifiers but the ones I listed can only use a single thermocouple. However, they use the SPI bus so you should be able to connect multiple modules to your Arduino, one per thermocouple. The first one uses three pins on your Arduino but each additional module can share the same Arduino pins for DO and CLK. It's only the CS pin that must be on a separate Arduino pin for each module because that is the pin that enables the module you want to communicate with. Having said that, I've only ever used a single module at a time because I only need to read one thermocouple.

What temp range are you trying to measure.
For normal/human temps (-40C to 150C), a DS18B20 might be a better and cheaper solution.
Leo..

Can I connect the sensor directly to Arduino? When the Arduino is fed from a 9V battery

oh but I see that one of its legs go to 5V, so how can I connect 5 sensors at the same time?! :confused:

You can connect a whole bunch of digital DS18B20 temp sensors to the same Arduino pin.
Because of the unique internal address, the Arduino can talk to one at the time.
All ground pins go to ground, all power pins go to 5volt (or 3.3volt for a 3.3volt Arduino), and all datapins go to one Arduino pin.
One pull up resistor is required between data pin and power, usually 4k7.
Leo..

thanks you so much!

Sorry for the ignorance, maybe I did not understand right .. can I connect 5 different thermocouples to the same 5V input? how?!

I wasn’t talking about thermocouples.
Thermocouples need special amplification (one per thermocouple).
The thermocouple itself is cheap, but the amplifier is not.
That’s why they are not often used for normal/human temps.
Again, what are you trying to measure
Leo…

I need to monitor temperature of each finger

Liz0905:
Can I connect the sensor directly to Arduino? When the Arduino is fed from a 9V battery

Which sensor?

Liz0905:
Sorry for the ignorance, maybe I did not understand right .. can I connect 5 different thermocouples to the same 5V input? how?!

Please explain exactly what you mean by "5V input".

Liz0905:
I need to monitor temperature of each finger

There are probably better options than a thermocouple for that purpose. Usually thermocouples are used for measuring very high temperatures that would destroy other types of sensors, like inside a pottery kiln.

maybe you know which sensor can I use for this purpose?

Thanks you!

Third time. What are you trying to measure.

Do you need temp sensors for the fingers of a glove? Normal human temps?

Maybe small 10k thermistors would do.
You just need one analogue input per thermistor.
Leo..

Wawa:
Third time. What are you trying to measure.

Do you need temp sensors for the fingers of a glove? Normal human temps?

Maybe small 10k thermistors would do.
You just need one analogue input per thermistor.
Leo..

Yes! That's exactly what I wrote before, I need to monitor the temperature of five fingers simultaneously.

Thanks you,
Liz

Lots of 10-pack or 100-pack small thermistors on ebay for a few dollars.
Enter “10k thermistor” in the search bar.
Leo…

Wawa:
Lots of 10-pack or 100-pack small thermistors on ebay for a few dollars.
Enter "10k thermistor" in the search bar.
Leo..

Thanks you so much!

Liz