Contrlling RGBLEDs connected to BBC microbit V2 with Mit App Inventor

Helllo once again.

I am trying to create an app to control RGB LEDs connected to the micro:bit.

From the codes, the instructions for the micro:bit to connect to the Mit Campanion worked with the micro:bit.

But when I click on the buttons created to switch the RGD LEDs on the app it does work.

The images show the design of the app and the code. I have also uploaded the coded for the micro:bit.

Can anyone help me figure out where the problem is?

Thank you.

The app of App Inventor uses the Io Pin Service.
I think the makecode is the follow.


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Which microbit extension are you using?
Probably it is much better to send commands via UART, interpret these on your microbit and set the io-pins using makecode on your microbit.
See here: The Internet of Things: Data Acquisition and Analysis for a tutorial.

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Oh okay, Let me try that and see.

Thank you very much.

Hello Ghica.

I am actually using the Bluetooth extension.

Of course you are using a bluetooth extension, but my question was, which one.
Actually it does not matter because you cannot address the io-pins this way, because all microbit extensions are flawed. You can only successfully use UART, read my previous post again. try the tutorials I pointed to, and then try your IOpins again.

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Alright, Ghica, Thank you very much.

I will try it and give you feedback.

Maybe I should have givne a bit more explanation. I have a tutorial about communicating with a microbit:

And the link to the internet of things tutorial I gave earlier ( has a more gentle explanation.
Except for the BLE extension mentioned in the Internet of things tutorial, you should use this one (200.0 KB) mentioned in my tutorial, to get the proper Android permissions.

At this moment you cannot address the IO-pins of the microbit directly from App Inventor, as I said. So, what you should do instead is send a command to the microbit via the serial interface UART, the microbit recieves this command and activates the IO-pins, using MakeCode. All explained very well in the IOT tutorials.
The last example in these tutorials is about watering plants, I think also do via the IO pins, so that should help you.

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Thank you very much @Ghica

My setup is working now :grinning:


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