App Inventor >>> Puck.JS/MDBT42Q transmitting of data

Hi Gordon,

at the moment I am trying to create a simple App Inventor application which should sends just a signal to Puck.JS or MDBT42Q to switch an digital output to high, while the button on the cellphone is pressen.

I´ve created a really simple test application with three buttons (1. Scan, 2. Disconnect, 3. Button for signal transmitting), furthermore a Listpicker to choose the BLE device.

I get the LED feedback from Puck.Js if I start the bt connection to Puck. So that seems to work but if I click on the third button to send something (e. g. a "1") I get no feedback. I am not sure, what I have to do on Espruino side. I started with the block diagramm at the Espruino IDE.

I used the following UUID´s on App Inventor:

UUID 6e400002-b5a3-f393-e0a9-e50e24dcca9e
UUID 6e400003-b5a3-f393-e0a9-e50e24dcca9e

Can you help?

Best regards

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I think the issue is the code you're using on the Puck.js side. Basically the Get Characteristic block you're using is something you do when you're trying to connect to another device.

What you need is When Characteristic Changed. In the example below, it's Characteristic 5678 on Service 1234 - you'd just have to update those in AppInventor.

The UART RX Characteristic you're currently using is being used by Puck.js itself to upload code, so you probably don't want to use that.

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Hi Gordon,

now I understand. Thank you very much!

Best regards