Suggestions for small BLE development board microcontrollers?(For wearable)

I am working on a wearable project that needs ble capabilities. I started out making sure the project was feasible and luckily I was able to figure it out. The bad news is that my tester microcontroller is way too big. I used an esp32 with the components being attached to a breadboard so that brings me to my questions.

What are your suggestions for the smallest BLE capable microcontroller? I came across the TinyPico and Beetle BLE which seem cool but I don’t know how easy programming these would be. Then i came across single modules like the ESP-WROOM-32 which seems very small but programming it seems more difficult than the other two options. Perhaps I’m also missing other options?

Additionally I have never actually soldered stuff before (I’m fairly new). That doesn’t mean I don’t want to solder stuff just if a suggestion requires an experienced solder it might be more hard for me.

----EDIT—

Due to confusion on why i’m asking this here is some context

"Here is what i am trying to achieve. I am working on a personal project. Something that if I can succeed in creating a prototype by myself I would be interested in working on a commercial/better version.

A button is clicked attached to wearable A → an LED on wearable A turns on → an LED on wearable B turns on.

The button is clicked again that is attached to wearable A → an LED on wearable A turns off → the same LED on wearable B turns off.

This works both ways A->B and B->A. The wearables are also going to be 100+km away from each other.

I was suggested to explore cell/3G micro controller development boards. This turned out to not be a good idea since it will cost a lot more and be larger than I would be comfortable with (I don’t want sim cards). I was told to explore wifi development boards. This turned out to not be a good idea since the wearables would need to be connected to the nearby phones hotspot since the people wearing the wearables will be on the move. On ios you can’t connect to wifi while also having a hotspot, that disqualified this option. I was told to explore bluetooth. This area is the current best path especially with BLE. I plan to connect a microcontroller (development board) via BLE to an ios app which then can communicate two iphones to eachother. When one iphone receives a message from a microcontroller it sends a message to another iphone which sends a command to another microcontroller. I have succeeded in creating this on an esp32 development board. This is amazing. I just need to make this smaller."

–EDIT–

Do to even more confusion I feel the need to clarify something. I have already accomplished this. This task is completed. I don’t need suggestions on how to accomplish this task. I need suggestions on small BLE development board microcontrollers that is all.

Wearable means battery operated too which probably rules out an ESP. Look at the nRF chips (Nordic).

czu001:
Wearable means battery operated too which probably rules out an ESP. Look at the nRF chips (Nordic).

I was thinking of incorporating a rechargeable option. Something like an Lithium ion battery.

Rechargeable or not, you’re going to want a low power controller (I assume). Compare the ESP to the nRF. Cypress makes modules too, but I don’t know if there’s a compatible Arduino library.

Adafruit has nRF.

A microcontroller is an IC (chip). The ESP32 microcontroller looks like this:

It's 6x6 mm

It's common for small scale manufacturers to use BLE modules, which combine a microcontroller, support components, the antenna, and often shielding. This is done because RF design and regulatory compliance is very difficult, so it's most efficient to pay a little extra for a module that takes care of all that instead of starting from scratch. An example of such a module is the ESP-WROOM-32:

It is 18x25 mm
There is an ESP32 microcontroller on that module, but you can't see it because it's hidden under the metal RF shield

Then you have development boards which provide a BLE module and the necessary support components in a format that's easy to use for prototyping and small scale projects. Here's an example of an ESP32 development board:

It is 26x49 mm

So I hope you can now see that asking "what is the smallest BLE microcontroller" really doesn't make much sense. Sure, there are BLE microcontrollers in smaller IC packages than the QFN48 of the ESP32 that we could recommend, but the 6x6 mm of the ESP32 microcontroller is a tiny fraction of the area of the ESP32 development board.

It would only make sense to be concerned about the microcontroller size if you were planning to make your own BLE board completely from scratch. Since the RF design and even the soldering involved in doing that is very difficult and you say you're fairly new, I really don't think that's what you want to do. It's true you could use the module, but you'll still need to add at least some of those other components that are on the development board and there's a good chance you'd end up with a board that's just as big by the time you were done.

So I think what you are really asking about is the smallest development board with BLE capabilities. Do you see now how important it is to understand and use the correct terminology? Too often, I see people talking about the "Arduino microcontroller". There is no Arduino microcontroller. Arduino makes development boards which have microcontrollers on them, but Arduino does not make microcontrollers. They just buy them from other companies and put them on their development boards.

You'll be much more likely to get a useful answer if you ask the right question.

the smallest BLE capable microcontroller

This not the right question to ask.

If you have a commercial product in mind, with the help of one or more professional engineers you will specify the functions, choose the required parts (the ICs are all very small), write the code and after thorough debugging and testing of prototypes, with the help of a skilled designer, you will put them on the smallest possible PCB, then subject that to exhaustive tests.

Taking the failures into account, redesign and retest as required.

take a few minutes and read what an X/Y PROBLEM is.

to sum up, you fail, you rule out things, you paint yourself into a corner
you ask, what is the smallest brush I can paint with ?

take a breath, start over.

you have a need to......
you want to control...
and measure....
and run on batteries
and would like bluetooth.

maybe a bluetooth module connected to a small microcontroller?

===

as a note the ESP32 has a low power core so you can run at greatly reduced power
It has a deep sleep, so you can run it from batteries

pert:
A microcontroller is an IC (chip). The ESP32 microcontroller looks like this:
It’s 6x6 mm

It’s common for small scale manufacturers to use BLE modules, which combine a microcontroller, support components, the antenna, and often shielding. This is done because RF design and regulatory compliance is very difficult, so it’s most efficient to pay a little extra for a module that takes care of all that instead of starting from scratch. An example of such a module is the ESP-WROOM-32:

It is 18x25 mm
There is an ESP32 microcontroller on that module, but you can’t see it because it’s hidden under the metal RF shield

Then you have development boards which provide a BLE module and the necessary support components in a format that’s easy to use for prototyping and small scale projects. Here’s an example of an ESP32 development board:

It is 26x49 mm

So I hope you can now see that asking “what is the smallest BLE microcontroller” really doesn’t make much sense. Sure, there are BLE microcontrollers in smaller IC packages than the QFN48 of the ESP32 that we could recommend, but the 6x6 mm of the ESP32 microcontroller is a tiny fraction of the area of the ESP32 development board.

It would only make sense to be concerned about the microcontroller size if you were planning to make your own BLE board completely from scratch. Since the RF design and even the soldering involved in doing that is very difficult and you say you’re fairly new, I really don’t think that’s what you want to do. It’s true you could use the module, but you’ll still need to add at least some of those other components that are on the development board and there’s a good chance you’d end up with a board that’s just as big by the time you were done.

So I think what you are really asking about is the smallest development board with BLE capabilities. Do you see now how important it is to understand and use the correct terminology? Too often, I see people talking about the “Arduino microcontroller”. There is no Arduino microcontroller. Arduino makes development boards which have microcontrollers on them, but Arduino does not make microcontrollers. They just buy them from other companies and put them on their development boards.

You’ll be much more likely to get a useful answer if you ask the right question.

Wow a whole lot of new information for me! When I mentioned in my original post I was working on an ESP32 I meant I was working on a ESP32 development board. “smallest development board with BLE capabilities.” that sounds like definitely what I should be asking. Do you advise making a new thread or just figuring it out in this one?

jremington:
This not the right question to ask.

If you have a commercial product in mind, with the help of one or more professional engineers you will specify the functions, choose the required parts (the ICs are all very small), write the code and after thorough debugging and testing of prototypes, with the help of a skilled designer, you will put them on the smallest possible PCB, then subject that to exhaustive tests.

Taking the failures into account, redesign and retest as required.

That’s sort of the current way I’m going. Although I feel I would much rather make at least a prototype on my own. Prove that I at least have the skills to build a semblance of an idea rather than just pay some engineers and designers to build it.

dave-in-nj:
take a few minutes and read what an X/Y PROBLEM is.

to sum up, you fail, you rule out things, you paint yourself into a corner
you ask, what is the smallest brush I can paint with ?

take a breath, start over.

you have a need to…
you want to control…
and measure…
and run on batteries
and would like bluetooth.

maybe a bluetooth module connected to a small microcontroller?

===

as a note the ESP32 has a low power core so you can run at greatly reduced power
It has a deep sleep, so you can run it from batteries

This is essentially what I’m doing and have already done. I started out with the needs then ruled out cell/3g driven microcontrollers, ruled out wifi based microcontrollers, ruled out regular bluetooth, settled on BLE, Bought an esp32 development board and was able to accomplish what I wanted on it. Now I just need to go smaller. So essentially I need to find the smallest development board with ble capabilities. Once I’ve figured this out I will make a wearable case and attach all the other tech to it. This will be much larger than the smallest possible device but it will at least be a semblance of my idea in a non-large size.

guanciale:
Do you advise making a new thread or just figuring it out in this one?

No. Please continue to use this one. It’s common for us to spend a little time determining exactly what someone is asking in their threads here. I don’t think anyone will be thrown off track.

guanciale:
That’s sort of the current way I’m going. Although I feel I would much rather make at least a prototype on my own. Prove that I at least have the skills to build a semblance of an idea rather than just pay some engineers and designers to build it.

This changes things because now we are also concerned about how the development board you use for the prototype will translate to the finished design. Is achieving the smallest size also going to be important for the finished design?

guanciale:
"smallest development board with BLE capabilities." that sounds like definitely what I should be asking.

Even worse a question, and not just because you will not be using a development board beyond the first prototyping stage.

As you obviously ignored the suggestion from #6, here the link. Get it now?

pert:
No. Please continue to use this one. It's common for us to spend a little time determining exactly what someone is asking in their threads here. I don't think anyone will be thrown off track.
This changes things because now we are also concerned about how the development board you use for the prototype will translate to the finished design. Is achieving the smallest size also going to be important for the finished design?

For the final commercial version, I don't know how small its going to need to be. It's going to be a wristband though. Right now I'm more focused on proving I can accomplish the solution in a reasonable size, if I need to reinvent the solution afterwards that's fine by me, I just want to prove I can at least get somewhere on my own. The size of my ESP32 development board along with all the other components is just way too big. Perhaps a solution 1/3 the size would be good, I don't know.

wvmarle:
Even worse a question, and not just because you will not be using a development board beyond the first prototyping stage.

As you obviously ignored the suggestion from #6, here the link. Get it now?

What's wrong with using a development board for a prototype? I'm not selling this in Best Buy, just simply wanting to experiment... I also think people are misinterpreting what I'm asking. This step is the result of multiple threads on multiple sites/forums. I pretty much state my main goal in every single thread I post in. If you'd like me to explain my thought process and not take my word for it, I'm more than happy to. The reason is I want the best solution. I'm just trying to experiment and wanna figure out what's best.

Here is what i am trying to achieve. I am working on a personal project. Something that if I can succeed in creating a prototype by myself I would be interested in working on a commercial/better version.

A button is clicked attached to wearable A -> an LED on wearable A turns on -> an LED on wearable B turns on.

The button is clicked again that is attached to wearable A -> an LED on wearable A turns off -> the same LED on wearable B turns off.

This works both ways A->B and B->A. The wearables are also going to be 100+km away from each other.

I was suggested to explore cell/3G micro controller development boards. This turned out to not be a good idea since it will cost a lot more and be larger than I would be comfortable with (I don't want sim cards). I was told to explore wifi development boards. This turned out to not be a good idea since the wearables would need to be connected to the nearby phones hotspot since the people wearing the wearables will be on the move. On ios you can't connect to wifi while also having a hotspot, that disqualified this option. I was told to explore bluetooth. This area is the current best path especially with BLE. I plan to connect a microcontroller (development board) via BLE to an ios app which then can communicate two iphones to eachother. When one iphone receives a message from a microcontroller it sends a message to another iphone which sends a command to another microcontroller. I have succeeded in creating this on an esp32 development board. This is amazing. I just need to make this smaller. That's all I'm asking. Your X/Y link doesn't really apply since all I'm asking is for smaller options than the ESP32 development board. I apologize if I seem to have worded the question wrong and should have said "microcontroller development board" instead of "microcontroller".

There are even smaller boards that offer BLE than the ESP32 boards; the BLE chips themselves are often also microcontroller based with lots of I/O pins (that normally remain unused - and I really don't know how to program them).

So suitable suggestions (even more so the "best solution") depend on the details your final application, which is still unclear, and goes way beyond the intended form factor. I for one wouldn't want to carry board as big as an NodeMCU-32 on my wrist. My wrist isn't that big. The ESP32 is a very powerful processor, includes WiFi as well, and is probably way more than you need (though if WiFi makes sense - for connecting to a mobile phone or so - the ESP8266 may be another option; the ESP01 modules are really small).

wvmarle:
There are even smaller boards that offer BLE than the ESP32 boards; the BLE chips themselves are often also microcontroller based with lots of I/O pins (that normally remain unused - and I really don't know how to program them).

So suitable suggestions (even more so the "best solution") depend on the details your final application, which is still unclear, and goes way beyond the intended form factor. I for one wouldn't want to carry board as big as an NodeMCU-32 on my wrist. My wrist isn't that big. The ESP32 is a very powerful processor, includes WiFi as well, and is probably way more than you need (though if WiFi makes sense - for connecting to a mobile phone or so - the ESP8266 may be another option; the ESP01 modules are really small).

I guess I wasn't clear in my description. I want a smaller option than the ESP32 (development board). That's what I am currently using. The NodeMCU-32 I agree is also too large. I just want options of BLE-capable development boards that are small enough for a wearable rough-prototype. I understand having a development board on a commercial version is a bad idea, I just want to make a rough prototype.

guanciale:
Here is what i am trying to achieve. I am working on a personal project. Something that if I can succeed in creating a prototype by myself I would be interested in working on a commercial/better version.

A button is clicked attached to wearable A -> an LED on wearable A turns on -> an LED on wearable B turns on.

The button is clicked again that is attached to wearable A -> an LED on wearable A turns off -> the same LED on wearable B turns off.

This works both ways A->B and B->A. The wearables are also going to be 100+km away from each other.

It took an awful long time to get that simple description. It should have been in your Original Post.

First thing that strikes me is that BLE has absolutely NOTHING to do with a system that must work over a distance of 100km. BLE will struggle at 100m (or maybe not even that).

For long distances you have two options. If both devices are within range of a WiFi router that is connected to the public internet you could use WiFi. If not, then you need to use the mobile phone system.

And because of the long distance your information will need to traverse several networks any one of which could introduce an unpredictable delay.

...R

I guess OP is thinking of something like wearable/BLE --> mobile phone --> Internet --> mobile phone --> wearable/BLE.

The small ESP01 would make this: wearable/WiFi --> Internet --> wearable/BLE. Where a mobile phone could be the WiFi access point the ESP01 connects to - or the other way around, with the ESP01 as access point.

wvmarle:
I guess OP is thinking of something like wearable/BLE --> mobile phone --> Internet --> mobile phone --> wearable/BLE.

That is not supported by this quote from Reply #10

I was suggested to explore cell/3G micro controller development boards. This turned out to not be a good idea since it will cost a lot more and be larger than I would be comfortable with (I don't want sim cards).

However what you suggest has the value of being practical :slight_smile:

...R

Robin2:
That is not supported by this quote from Reply #10

That I interpreted as "in the wearable itself".

The complete boards (MCU + mobile connection) that I have seen are indeed bulky, OTOH the SIM800 modules and siblings are not, and could host a Pro Mini on the back.

Robin2:
It took an awful long time to get that simple description. It should have been in your Original Post.

First thing that strikes me is that BLE has absolutely NOTHING to do with a system that must work over a distance of 100km. BLE will struggle at 100m (or maybe not even that).

For long distances you have two options. If both devices are within range of a WiFi router that is connected to the public internet you could use WiFi. If not, then you need to use the mobile phone system.

And because of the long distance your information will need to traverse several networks any one of which could introduce an unpredictable delay.

...R

I have already made the solution mentioned which is why I haven't explained it in more context. Since i have figured it out I didn't think it was important to justify my questions. I will try to explain it further. The wearables will be 100km+ away from eachother. To tackle this gap. I am connecting the wearables via BLE to an ios app on phones that will always be nearby. Phones are usually not more than 5 meters away from the person who owns them. So in terms of distance it will be Wearable A->(Gap of 1 Metre)->Iphone A->(Gap of 100km+)->Iphone B->(Gap of 1 Metre)->Wearable B

The ios app will send information over a server to communicate the two phones (that are 100km+ apart). The simplest explanation is:

Button click on Wearable A->BLE notification from Wearable A sent to ios app on Iphone A->Ios app sends the information over a server to another phone with the same ios app->ios app in Iphone B receives the information from ios app on Iphone A->ios app on Iphone B pushes BLE information to Wearable B. This works vice versa.

I don't need help figuring this out. Please stop second guessing everything I have typed since this solution is the culmination of many, many threads/posts of users discussing what the best possible solution is. I explained why Wifi and a Mobile Phone system won't work in response #10. I don't need help with figuring out how to accomplish this task. This has been figured out and accomplished. I just need to make the current wearable smaller, that is all. I would really like someone to answer the threads topic of "What are the smallest development boards with BLE capabilities?".

guanciale:
this solution is the culmination of many, many threads/posts of users discussing what the best possible solution is.

Which we don't know, nor do we know all your other requirements.

Why don't you ask in any of the previous threads - where people actually know wtf your project is supposed to do and look like etc - for the best BLE solution for your specific problem?

guanciale:
"What are the smallest development boards with BLE capabilities?".

That would currently be the ESP32 boards. But you rejected those already.

To go smaller, build your own PCB. There exist really small BLE modules. You need a single button, an LED and BLE comms - a 3x3mm ATtiny can easily do this.

wvmarle:
Which we don't know, nor do we know all your other requirements.

Why don't you ask in any of the previous threads - where people actually know wtf your project is supposed to do and look like etc - for the best BLE solution for your specific problem?

That would currently be the ESP32 boards. But you rejected those already.

To go smaller, build your own PCB. There exist really small BLE modules. You need a single button, an LED and BLE comms - a 3x3mm ATtiny can easily do this.

The requirements have been stated many times. Small BLE capable development boards. That is it. I don't need help in figuring out if wifi/cell/ble is best. I don't need help figuring out if using an ios app to communicate over a server is a good idea. I don't see how going into massive detail helps people answer my question. It only derails the threads topic.

The ESP32 development board is not the smallest one, if you read my original post I suggested possibly using the TinyPico or Beetle BLE which are quite smaller. This whole post was me trying to see if there are other development boards I had missed and what people thought of the TinyPico/Beetle BLE. This thread has been a waste of time.