Create your own App! Control an ESP32 (Arduino) via Bluetooth - Part 2

IMPORTANT UPDATE (30.09.2022): MIT App Inventor updated their Bluetooth library without backward compatibility. Might you have downloaded this code from my Github page before 30.09.2022, please download the updated version. Changes only affect the general Bluetooth connection stuff discussed in Part 1.

Part 1 of this series focused on controlling an ESP32 via Bluetooth with your phone (using MIT app inventor). In part 2 I show you how to create bi-directional communication so that the ESP32 can send information back to the phone. Might you have missed part 1:

Please make sure your ESP32 has Bluetooth to make this work. I used the ESP32-WROOM-32D. For creation of the app I use the MIT app inventor in combination with the MIT AI2 Companion. Note that this code will only work on Android. The reason is that BluetoothSerial does not work on an Iphone. For an Iphone only BLE works. Code for this will follow shortly...

If you want to code along, this is the starting point:

For the final code, please refer to:

MIT App Inventor:

Might you have problems programming the ESP32, pls refer to:

Have fun with the code and let me know in the comments below what application you are working on :-)

[MrPanrob]

finalmente dopo tanto cercare ho trovato lei che mi ha incoraggiato ad evolvermi in questo mio "gioco" nonostante il problema di comunicazione e grazie al traduttore sono riuscito a far funzionare esp32 con mit inventor. grazie per l'impegno e il suo modo di spiegare, saluti Roberto

[stever]

I watched part 1 and it was amazing. Thank you for the detailed instruction, I’m a new user of the Esp32. I would have never thought I could do this. This will take my projects to the next level. I subscribed.

[qzorn]

wonderful video. i have been watching several MIT-inventor videos in comparison to the RemoteXY, which shows the remotexy-Arduino code to download to the Arduino-IDE. 🤥This video part-2 makes it clearer where to Arduino IDE code is located. Most MIT videos go in detail on the fun programming stuff. now, i can starting using MIT and the Arduino-IDE. thanks you.

[MyTawat]

I’m new to hardware. You videos is very helpful. Help reducing my learning curve.

[bobdurk]

So far so good, your tutorials and explanations are really helping to reduce the learning curve. I now want to take a control sketch I have working and see if I can use the BT App to control my audio system. Just a baby step, but it should work as proof of concept.

[armancodeq]

U know some people r angles....bro ur the one.

[joebotics]

thanks for the great tutorials!. I just had the apps working on a Samsung S10+ and ESP32.. WINNING !!!

[mobileiotapps]

Hey, thank you so much for the tutorial it really helps, I was just looking for other ways to create an ESP32 app by using MIT App inventor.

[DavidSunshine]

Thank you you for making an easy to follow video! Really appreciate your hard work in sharing your knowledge with the world! Very helpful for us who are brand new to Arduino programming. I'm trying to create an APP that can control an ESP32 to turn on fans based on temperature sensors, so this is perfect for sending and receiving temperature settings and readings back and forth!

[DWM]

man, your videos are awesome, thank you!!

[srikirthikandala]

Thank you so much for the tutorials. They have greatly reduced the learning time and gave me a head start. I was wondering if you could make small video on plotting graphs in the app

[ibendiben]

Dank voor je tijd en uitleg. Spreek je Nederlands? En kom je wel eens in de buurt van Den Haag?

[ashokkumarSa]

we can control all audio for call recording purpose

[MARvelousD]

Learning a lot from this 2 video tutorial, btw i am making an app for power monitoring system where the user can view the kwh, and some other features, i a sending data back to app using esp32

[banchasaoraso]

Very goog. After I do with your project. It can operate. Thankyou.

[hidayat]

Thanks for the video. Actually I always get "bluetooth permission" problem when trying MIT inventor test. So finally I used kodular and didn't have the same problem.

[boultifnidhal]

Hey, thank you so much for the tutorial. I'm just having a little problem. the screen that I connect to the ESP is not the same screen that I work with. So, how can I distribute the bluetouth connexion to the whole application

[sridevipindi]

hi could u guide me how to send adc values to mit app...
// variables to store measure data and sensor states
int BitsA0 = 0;
float VoltsA0 = 0;
void loop() {
BitsA0 = analogRead(PIN_A0);
// standard converion to go from 12 bit resolution reads to volts on an ESP
VoltsA0 =BitsA0 * 3.3 / 4096;
String adcValue = String(VoltsA0);
Serial.println(adcValue);
if (ESP_BT.available())
{
ESP_BT.println(adcValue); if i write ESP_BT.write(adcvalue)....it is throwing an error
// otherwise if i write ESP_BT.write(VoltsA0) when i press any button the numerical value gets displayed //on the mobile screen...and everytime the number get increased by i have to press any button
}
my doubt is that automatically the adc value should be displayed...without pressing the button
when we rotate the pot in the serial monitor the adc value updates automaticlly....similarly as long as the bluetooth is connected, when we rotate the pot the value should be updated on the moblie screen too...without pressing any button....could u guide me pls

}

[Chillandrelax]

Hi, how do we enter two numbers in two separate textboxes and that would be sent to the Arduino? But only one or both textboxes can be used at any time to change the corresponding values of the variables in Arduino, with a single "Send" button in app for both textboxes. Thanks in advance...

[abishek]

Hey, apart from trial and error how do get precise delays, say for 10 seconds?