Arduino to Android BLE Receiving Corrupted String Data

MIT App Inventor Help
#1

Hi

I have searching for hours trying to find a solution to this. I have an arduino connected to an HM-10 BLE module. If I use an app such as Bluo to see the text I am sending via the HM-10 it displays as expected but when trying to get the same data in AI2 all I get is a corrupted string. It is always the same data regardless of what I send.
I’ve only been at his a couple of days so it’s all new to me but from what I have seen on the web this should work. Blocks and sketch attached.

I must be doing something wrong but I can’t figure it out so if someone could point out where I am going wrong it would be very much appreciated.

Many thanks

Rich

#include <Wire.h>
#include <AltSoftSerial.h>

AltSoftSerial BTserial;

void setup()
{

Serial.begin (38400);
BTserial.begin(38400);
}

void loop(){
Serial.print(“Test”);
BTserial.print(“Test”);

delay (1000); // pause a second
}

BT_Van.aia (167.8 KB)

Screenshot_20191231-182028
Screenshot_20191231-1820281440×2960 175 KB

#2

That 38400 bps might be too high.
9600 bps is a more attainable common denominator default speed.

#3

Thanks. I should have said, I started with the default of 9600 and it didn’t work so I was playing with different rates to see if it helped.

#4

Have you seen this tutorial from the AI2 FAQ?
http://www.martyncurrey.com/arduino-hm-10-and-app-inventor-2/

Note the Register for Strings block usage in Arduino Sketch. Example Project Part 2: Turn an LED on and off 2way control

Also double check for wiring errors (crossed transmit/receive wires), it caused garbage for a user in the old forum once.

I’m opening up this thread to more experienced HM-10 users.

#5

Here’s a custom search for HM-10 in the old forum:
https://groups.google.com/forum/#!searchin/mitappinventortest/HM-10%7Csort:date

#6

This thread might help, it has sample code for both sides:
https://groups.google.com/d/msg/mitappinventortest/2KPxDAAPMRA/x6ZVLv5rCgAJ

#7

Thank you. That was the tutorial that I was using. I’ll have another look at it, I must have missed something out somewhere. As you say the string registration could be it.
I’m pretty sure I can rule out a wiring issue as I’m receving the data correctly in another ready made app.

#8

Now working.
I was using ReadStrings when it wasn’t necessary. I needed to Register for Strings and use the When Strings Received process.
Thanks again for pointing me in the right direction.

BLE ESP32. Bluetooth. Send. Receive. Arduino IDE. Multitouch
#9

Thanks for telling us what worked, and
Happy New Year!

#10

I also faced the same problem.
Please give me any suggestions.
I used Register for string block and read-string block.

#11

Have you compared your code blocks with the tutorial referred to earlier in this thread?
http://www.martyncurrey.com/arduino-hm-10-and-app-inventor-2/ 8

#12

I gothrough this codes and applying into my code block. Then my app is going to hungout state.

#13

Post your exported .aia file and .ino file here.

#14

AQI_APP_1_0.aia (162.5 KB)

I interface the sensors with the MSP430 microcontroller so I can’t upload the .ino file.

#15

So show us the C code. Any kind of source code.
Also tell us about the BLE device info on the MSP430.

#16

Also, your BLE ReadStrings block is unnecessary if you registered for strings.

#17

Ok, I will try this suggestion and i will shere the result.
But I can’t share the MSP430 uc programming code.

#18

My BLE device is HM10S.
I also try with the use of BGx13P. Same problem I faced.

#19

Double check that your two connection strings (UUID, etc) are right for HM-10.
See the Donnelly video at FAQ Section: BlueTooth/BLE and HM-10 two thirds through for how to double check those.