Have an idea for an Extension?

@mike @Juan_Antonio I think that Thing has sense if android sends active notification through internet (not necessarily through wifi connection) and when esp8266 detect a new string or something on the web page it gets all the info for display information. It could be even more interesting connect the android app via qr code or an alphanumeric code to the esp8266, in this way just the esp8266 verified from android could get notification from that device.

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@mike @Mattia_Pozzato
To work efficiently with Notifications, you must use Services, App Inventor does not work with Services.
Check out these links:


@Juan_Antonio so with App Inventor is impossibile to do what I need, is it?

I don’t know if someone can and wants to do it.

More information on this topic:

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@Ken if you want I’ve got some time to dedicate :grinning:

Id have an idea. Since this school year im working with mikrocontrollers in school and for my project im working on a “Infinity Led Cube”. I thought id be great to controll it with an app so i started to work on it. Up to now i have some Ledmodes and I send the data to my esp32 through UDP (thx to Ullis Roboter Seite). Now i would love to add a mode to analyze and view Songs. There are a couple of solutions online but since my project has a 50€ cap to spend on i cant really buy microphones, chips, resistor and capacitor sets. So i started to search for another solution. I came across some JS Videos but they dont really do the job for me. They rely on microphone input. The problem with that is, that when you play a rather quiet song or anything it wouldnt work that well and a “song picker” wouldnt allow me to play Youtube/ Soundcloud songs. Thats why I tried to make a extension for MIT App Inventor to take the audio output of the Smartphone and analyze it and then send the data to my esp32. The only problem is that I just began learning C++ this year and for this little thing it would take a lot of time for me to understand and write the extension in Java. So to come to an end:

The idea:
A (maybe FFT based) Audio-output anaylzer, 8 baneded, that returns strings (im sending strings through my UDP). The big thing is that it shouldnt rely on a microphone. I should just take the output (so i can use Bluetooth i.e.)



PS: If you´d like to see the code from my esp32 id be more than happy to send it to you. :slight_smile:

Not long ago, to ai2 was added dictionary. You can do an extension that would sort the dictionary by key.

See the Sound Analysis extension here (uses device micrphone)


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I have very little experience with microcontrollers.
My son and I used a ProMicro to make a midi device a few months ago but that is all.
I had to Google esp32 to figure out what it was…

Unfortunately I don’t think I’m the right person for this particular job.

Currently an extension is unable to add Service elements to the manifest so this isn’t possible without having to manually editing the manifest after the .apk is compiled.

Oh yes, but it still uses the microphones input. I wanted to use the audiooutput for the input…

Bonjour Ken,
J’utilise la norme NFC Rfid pour ouverture et fermeture de portes sécurisées par vigik. Le lecteur NFC d’app inventor n’étant pas complet je me suis détourné d’une fabrication d’APP. Vous serrez t’il possible de faire une extension qui lit l’ID unique du tag. Je n’ai besoin que de l’IDU mais je présume que d’autres auraient besoin de pouvoir modifier ce dernier.
Merci de votre travail qui nous arrange grandement.
Cordialement, Patrick

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@Patrick totally agree with you.

What are the main issues?

@Ken @Patrick issue is, as far as I can tell, AI2 doesn’t let you use NFC between phones and no body wants to talk about it. See here:

See the documentation:

For now this component supports the reading and writing of text tags only (if supported by the device)

It looks like Patrick is using a Vagik fob.

@TIMAI2 thank you for sharing. Unfortunately, can’t find working example of phone to phone NFC text tags.

@ken that’s cool and all, but most powerful use cases are NFC phone to phone. Able to do everything and more if this is possible you could with a fod. Can always pick up a cheap Android treat it like a fob. Apple didn’t just wake up a couple years ago and randomly decide to include NFC in all their devices going forward …

Article from 2013 on apples stance on NFC:

Article from 2017 on apples stance on NFC:

Wanted to point out the adoption from Apple since we well soon enough be able to compile our apps for Android and ios. Bluetooth and qr are useful in certain cases but programmable NFC where we can go phone to phone is scary useful. I would say extension is a good idea but it is so core to the future of AI2 that it should maybe be focused on by @ewpatton and his team. But if you make an extension we wouldn’t stop you :slightly_smiling_face:

You won’t !

from Wikipedia:

Every active NFC device can work in one or more of three modes:

NFC card emulation
Enables NFC-enabled devices such as smartphones to act like smart cards, allowing users to perform transactions such as payment or ticketing.
NFC reader/writer
Enables NFC-enabled devices to read information stored on inexpensive NFC tags embedded in labels or smart posters.
NFC peer-to-peer
Enables two NFC-enabled devices to communicate with each other to exchange information in an ad hoc fashion.

As I understand it, the AI2 NFC component falls into the second category.

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@Ken @Taifun @TIMAI2 (and anyone else who knows how to do extensions) can we please work together on “NFC peer to peer” extension?

CC: @Hossein @Andres_Cotes