Hi, I am new to arduino. I would like to read K-type thermocouple data via a MKR thermal shield. I have two questions if anyone can kindly help me with.
Can I attache MKR thermal shield on Arduino Nano 33 IoT? I read Nano 33 IoT is similar to MKR WiFi 1010.
Could you share a picture showing how to connect MKR thermal shield to the Nano 33 IoT please?
Thank you in advance for your help.
lucymamaxx:
- Can I attache MKR thermal shield on Arduino Nano 33 IoT?
Yes, but you can't plug it directly in to the board as you could on one of the MKR boards because the Nano boards have a different form factor. You'll need to use some jumper wires to make the necessary connections, which negates the benefits of using the MKR Therm Shield vs using a MAX31855 module.
lucymamaxx:
2. Could you share a picture showing how to connect MKR thermal shield to the Nano 33 IoT please?
No picture, but here are the connections you need to make:
VCC | VCC
GND | GND
10 | 12
9 | 13
A4 | Any free pin other than A4 or A5
On the MKR Therm Shield, the CS pin of the MAX31855K is connected to pin A4. The reason I recommend against connecting that pin to A4 or A5 on your Nano 33 IoT is because on the Nano 33 IoT, A4 and A5 are the I2C bus, which is connected to the crypto chip on the board. If you use A4 and A5 for anything other than I2C on then you will not be able to use the crypto chip and some WiFi operations won't work. If you're using the Arduino_MKRTHERM library, you can configure any CS pin you like via the constructor. For example, if you used pin 10 for CS, you would configure it like this:
THERMClass MAX31855(10);
And then use that object instead of the default THERM object:
Serial.print(MAX31855.readTemperature());
There are other libraries for the MAX31855 you can use as well and I think most of them will let you configure the CS pin in some similar manner.
Dear pert,
Thank you very much for your generous advises. It seems like I'd better opt for other shield instead of MKR shield since it doesn't provide any conveniency in term of connection.
May I ask which thermal shield you would recommend for Nano 33 IoT which is easy and simple to connect and relatively easy to program (library support, etc.). You've mentiond MAX31855 module, is this one you would recommend?
Could you kindly show me how to connect your recommended shield to Nano 33 IoT please?
BTW when you mentioned Nano 33 IoT pin 12 and 13, they are marked as D12 and D13 on the board?
Thank you very much in advance.
lucymamaxx:
May I ask which thermal shield you would recommend for Nano 33 IoT
I haven't ever seen shields made for the Nano form factor.
lucymamaxx:
relatively easy to program (library support, etc.).
A MAX31855 is a MAX31855 no matter what shape of PCB it's soldered to or who sold it to you. Any of the several MAX31855 Arduino libraries will work fine for all of them.
lucymamaxx:
You've mentiond MAX31855 module, is this one you would recommend?
MAX31855 is the thermocouple amplifier chip on the Arduino MKR Therm shield. That's the chip I have experience with. There is also the MAX6675, which is cheaper, but has a bit smaller temperature range.
This is the MAX31855 module I use:
with this library:
https://github.com/RobTillaart/Arduino/tree/master/libraries/MAX31855
lucymamaxx:
Could you kindly show me how to connect your recommended shield to Nano 33 IoT please?
Just the same as I told you in my previous reply.
lucymamaxx:
BTW when you mentioned Nano 33 IoT pin 12 and 13, they are marked as D12 and D13 on the board?
Correct. The "D" stands for "digital".
Dear Pert,
Thank you so much for your kind reply and pointing me to the right direction. I found very detailed tutorials on how to connect the thermocouple to amplifier to arduino. I still have couple of questions if you can kindly help me with.
Showing in the following pictures attached, is the adafruit MAX31855 amplifier already have soldered on pins or do I need to solder them on myself? Do you find a small capacitor is necessary?
Also, what wires can I use to link arduino pins and the pins on the amplifier? Are those female to female jump wires alright?
Is it correct that I need to link Nano's "3.3V pin" as marked on the board to Vin pin on the amplifier? The other 3Vo pin, is this a output voltage pin?
Many thanks in advance again! Really appreciate your time on my very ametur questions...
Lucy
In addition, Do I need to solder the K-type thermocouple adopter onto the amplifier or that is just insert into the board? Many thanks.
lucymamaxx:
Thank you so much for your kind reply and pointing me to the right direction.
You're very welcome. I'm glad if I can be of some assistance. Luckily, I have a good deal of experience with the MAX31855 due to having used it in an Arduino-based custom temperature controller for my glass annealing kiln.
lucymamaxx:
is the adafruit MAX31855 amplifier already have soldered on pins
No. The header pins are not soldered, nor are the screw terminals for the thermocouple on the Adafruit module. The board comes with the header pins and the screw terminals, but they are not soldered. It does mean extra work, but it also makes the module more flexible in case you preferred to use some other sort of connections.
You can buy similar MAX31855 modules with soldered pins and terminal on eBay if you prefer. At the time I did my project, the price difference between the Adafruit product and the ones from China was not so big and I decided that for such an important part of my project I wanted to be sure to get quality parts. Months later, Adafruit contacted me to let me know they had discovered through their own investigation that the manufacturer of the MAX31855 had made a manufacturing error on some of their chips that caused them to not work correctly. They gave the date codes of the affected chips and offered to replace any I had received. It turned out I did have a couple of these in the backup modules I had purchased (though luckily the one in use in my kiln controller was good) and Adafruit sent me replacements for those modules without even requiring me to return the bad ones. I'm quite certain I never would have gotten that level of customer service from the eBay sellers of the Chinese MAX31855 modules.
lucymamaxx:
Do you find a small capacitor is necessary?
No. If you compare that picture to the one on the Adafruit product page, you'll see the Adafruit module has that capacitor built in, while the module in your picture does not.
lucymamaxx:
Also, what wires can I use to link arduino pins and the pins on the amplifier? Are those female to female jump wires alright?
Yes. Those will work.
lucymamaxx:
Is it correct that I need to link Nano's "3.3V pin" as marked on the board to Vin pin on the amplifier?
You can do that, but I think it's a better idea to connect the Nano's 5V pin to the Vin pin on the MAX31855 module.
lucymamaxx:
The other 3Vo pin, is this a output voltage pin?
Yes. That just provides a 3.3 V output from the voltage regulator on the MAX31855 module in case you have a use for it.
lucymamaxx:
Do I need to solder the K-type thermocouple adopter onto the amplifier or that is just insert into the board?
That's the screw terminals I mentioned above. You definitely need to solder them. If you just insert it into the board you won't get a reliable electrical connection and you'll have problems with your thermocouple readings.
Dear Pert,
Thank you very much for your kind advises!
Another question that I find it is very difficult to find answers online is how to power Nano 33 IoT using a battery. I am thinking of either to use a lithium battery of 3.7V (Lithium Ion Battery Pack - 3.7V 6600mAh : ID 353 : $24.50 : Adafruit Industries, Unique & fun DIY electronics and kits) or a battery holder along with 3 AAA batteries to give 4.5V (3 x AAA Battery Holder with On/Off Switch and 2-Pin JST : ID 727 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits). To power Nano 33 IoT, I plan to connect battery positive to Vin Pin and negative to Ground.
However, this is nothing online from Arduino Nano 33 IoT — Arduino Official Store what the acceptable battery voltage range is for Nano 33 IoT. It only mentioned that it operates at 3.3V and the USB power is 5V? I just wonder if you have any experience of powering it by a battery whether the above two options will work. If they don't fit with Nano 33IoT, do you have any suggestions which battery I should use?
It looks like from the battery or battery holder picture, then end of the wires has a adopter similar to a female jump wire. Can I just plug this onto male pins of VIN/GND?
Many thanks in advance.
Lucy
You have two options for powering the Nano 33 IoT:
The 3 x AAA batteries should work, but they are at the very bottom of the allowable voltage range at full charge so you are probably not going to be able to use the full capacity of the batteries. A 4X pack would be better. Note that if you're using rechargeable batteries, they only provide 1.2 V when fully charged.
A USB power pack (which provides 5 V) would be another option.
lucymamaxx:
It looks like from the battery or battery holder picture, then end of the wires has a adopter similar to a female jump wire. Can I just plug this onto male pins of VIN/GND?
I don't have a connector like the one on the battery pack. I can't tell from the picture of the lithium battery which connector it uses. The product description says it's a "JST" but that's stupid because JST is a connector manufacturer that makes hundreds, if not thousands of different types of connectors. On the common battery connectors I do have, you can connect them to the male header pins.
Dear Pert,
Thank you very much! Thank you for pointing out the voltage range for Vin Pin. I just realise this is written on the outer package of Arduino where I really need to look at first.
In terms of how long batteries will last, Can I use the capacity in terms of mAh divided by the current? May I ask if you know what is the normal amp running through Arduino Nano 33 IoT. I found the max.value of 40mA when using pins as output, but this seems a lot and the batteries of AA rating with 2400mAh won't last very long under this amount of current (about 2.5 days).
Also, if I am not using the the full voltage of the batteries, does it mean I can use the battery for longer time?
Thank you very much in advance.
Lucy
The thing you need to understand is that the voltage of the battery drops as its energy is drained. Here you can see the voltage vs mAh of a typical AAA alkaline battery:
lucymamaxx:
May I ask if you know what is the normal amp running through Arduino Nano 33 IoT.
One significant factor is the use of the WiFi radio. This takes a lot of power. Another factor is whether the ATSAMD21 microcontroller and the NINA WiFi module is left continuously running or put to sleep whenever possible.
Dear Pert,
Thank you very much for this chart and your detailed explanation. So what really matters is when the battery voltage (say 4 AAA batteries, 6V) drop down to 5V, that is the length of my usage time. In which case, does it mean the higher voltage I use (max.I can use is 21V, so split into individual battery, the voltage limit is a lot lower) the longer it will take to reach 5V limit?
My application is to use Arduino Nano 33 IoT to read the thermocouple data monitoring a oven on the shop floor and transmit the logging data via WiFi to a database and the data collection will be always on. So I do need to use the WiFi non-stop. And I am hoping to use batteries that can last a long period of time, most likely 1 year or 2. In this case, what current ampere do you reckon I should use to calculate the battery life?
Many thanks in advance.
Lucy
I just read a article saying that just to power an arduino requires 15mA due to all of its LED/internal components, etc. And seems like the only way to power an arduino for a long time using battery is to build an arduino from scratch losing all those energy consuming components which probably too much work for me. Plus the costs of so many batteries.
Maybe alternative I should use a wall socket instead? In this case, what do I need to link the socket to arduino? If I use electricity directly from socket, at 5V and 15mA, it only use 0.657kw electricity per year and cost next to nothing anyway.
Many thanks.
You can use a cell phone charger plugged into the USB jack on the Nano.
Thank you very much, Pert!
Yes, plan to use a 5V phone charger to power it directly.
