Need help with ESP32 Servo control app

5v is on left top connector on the esp32c3 see picture above in this post


Yes. But that is a power rail pin. There is a voltage regulator on that board that regulate the 5V to 3.3V because the ESP32 is 3.3V device. So the output pins also provide only 3.3V.
Do you see that 5 pin IC?

That is the regulator:

ME66211 3V3
Not sure it is the same type on every manufacturers board but it is a 3V3 regulator.

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I agree with @Usane,
typically the 5 V is the input supply to the board, then the voltage regulator "creates" the 3.3 which is also supplied on the relevant pin, and therefore used to supply an external device @3.3 Vdc.
Furthermore, for sake of my own knowledge, I've searched on the web a data-sheet of the Super Mini, and I've not been able to find a confirmation regarding the 5 Vdc I/O capability. To solve this doubt, if you have on your desk a Super Mini, you can supply it with a +5Vdc, then write a HIGH to a digital output (i.e. GPIO0) and measure the output voltage with a DVM: you shall then read or 3.3 or 5 Vdc.
Therefore, if the output voltage is 3.3V, for a better space utilization and less wiring, you can forget the Super Mini and use a Mini ESP in which the BT is included,
The chunks of code (Arduino and AI2) that I've sent you are working fine for me, I've tested them before posting, so if you have an ESP32 and a phone, or pad, you should be in degree to use them (once Android >=12 permisions granted).

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Thanks both for your input..
I will try out the Hc-05 way first cause therefore is enough find (good for me as " slow" arduino C learner, and then will go on trying out other ways.
Hopefully this week my new Esp32 boards will come in cause the last 2 Chinese boards things dont work...
@uskiara What esp mini do you mean ?

Thanks again
Nb i made an example app following a tutorial for MiT servo to try out

Dear @martijn, for example this one:

(Amazon Italy 'cause I'm Italian :grimacing:).
Ciao !

Thanks Us,

I know this ones, even think i have them lying around somewhere...
Question the esp32-C3 supermini has bluetooth onboard i think ?


Hi @martijn,
Question the esp32-C3 supermini has bluetooth onboard i think ?
Probably yes, type BLE (I'm not sure about the "classic" BT). To use the BLE on Ai2 side you shall use the extension written by E.W.Patton

Though the BLE BT is more complicated than the classic BT, the advantage is that it isn't a point-to-point, so you can connect more boards to one app.
You can find a lot of topics on the matter (BLE) by searching the community.
Best wishes.

PS, if you continue to experiment with the HC05, please be aware that it is only a classic BT shield.

He can do it, but there is no meaning for it.The documentation clearly states it is 3.3V

The output is the same. It cannot create 5V from 3.3V. Surely not internally, and there are no external component on the board to do it.

Supermini has BLE, as far as i know.

Sure :slight_smile:

Hello mates,

I made this to learn and try out MIT app and Bluetooth( i used a Nano )

Not real difficult to make and i got everything working untill i want to start the connection with bluetooth,
(if i press the bluetooth button on first picture ) sadly this happens.
(see picture 2)

i get a black screen, but in the youtube movie the bluetooth module comes up....
i got all the connections right and the bluetooth HC-05 module is working

What am i doing wrong ??
i have android 12 ...


Hi @martijn,
it seems that you are facing permission issues.
To verify if the communication between your phone and the HC05 is working, please use the following app (free) from ghoogle playtore:
Serial Bluetooth Terminal

Once you are done with that and you have verified that the communication works (in terms of hardware and phone <=> Hc05 compatibility), you can go deeper in your app.
Have you perhaps used my code (both AI2 and Arduino) the I've posted at the beginning of the thread?
Have you granted the cossing of Tx and Rx wires between Nano and HC05 ?

HC05 and Arduino are fine and connected....
Sadly your code does not work

Got the BlueToothSerial.h installed :grin:

Question :
Are the tx and rx pin on nano and uno on same pins 10 , 11?
Might be there is the problem?


Not necessarily !
The pins that SoftwareSerial uses (as far as I know) shall be capable of PWM, so you can use other pins provided that they feature the PWM capability. Im my drawing, that I posted at the beginning, the pins were D2 and D3. please refer to that drawing an take care of the wiring, as well !
PS The same sw that I sent you is working for other users (just posted to them yesterday). Have you changed the IP address of the HC05 in the AI2 block ?
The code that I've sent contains my HC05 address in a text constant, you shall overwrite it with your HC05 address.
Your Arduino Nano code should look like:

Can u send me that code ?
your app and the code i downloaded again from above part dont work sadly
i changed the HC-05 adress again but no luck at all....

starting to become a bit frustrating...


OK, you can find it attached.
I've just modified it to help another user that wanted to acquire a pushbutton and send its value to the app, nevertheless, this added part isn't influencing the transmission.
BT_Monitor_Nano.ino (3.0 KB)
Hoping it can help.
PSThe Serial BT Terminal app works ?

Ok ty
The serial bt app works and connects the HC-05 with my app on my phone
no probs there

NB might it be my phone does not download the apps from MIT right ? i use the scan QR code method

I can't do nothing with your app, and i keeps hanging, i cant push buttons or do anything....

So i dont know whats going on.... pretty strange it does work with others and doesnt overhere.... frustrating....

Will try old phone this evening....

Hi @martijn_vd_brakel,
I'rewritten both AI2 and Arduino codes and checked again on my desk (I have a HC06 but is the same in terms of coding and performances).

BT_Monitor_Nano.ino (3.1 KB)

Please take care of line 25 where I've set the baudrate between HC06 and Nano: if you see garbage(on both sides, AI2 and Nano serial monitor) this means that the baudrate is incorrect. Then try 19200 or 38400.

As far as the AI2 code is concerned, I've modified it in order to allow the selection of the (paired) BT devices reachable by the phone : just tap on the grey area named BTdevices, and then tap on the wanted address when shown in a list.
Hit on the CONNECT pushbutton: the label BT connected shall become green. Otherwise a popup appears to warn the insuccess.
Once connected, by pushing any button A,B,C you should read the feedback in the cyan label.
BT_to_Arduino.aia (26.3 KB)

After the apk build, I use the download apk:
Hoping now you can get rid of this issue :muscle: