White screen when i press on start button

Lynn1 · May 24, 2026, 7:39pm

hello , i have my project due tomorowand the app isnt working , when i pres start butto , all i get is a white screen and i dont know wher

Newon1Screen (2).aia (14.0 KB)

e the probem is from , please if someone can help me

ABG · May 24, 2026, 7:42pm

Also up load your sketch code so we can compare what you send to what the app expects.

Lynn1 · May 24, 2026, 7:45pm

// =====================================

// BED SORE PRESSURE MONITOR SYSTEM

// Arduino Mega + HC-05 + 9 FSR Sensors

// =====================================

// -------- SENSOR PINS --------

const int fsr1 = A0;

const int fsr2 = A1;

const int fsr3 = A2;

const int fsr4 = A3;

const int fsr5 = A4;

const int fsr6 = A5;

const int fsr7 = A6;

const int fsr8 = A7;

const int fsr9 = A8;

// -------- BUZZER --------

const int buzzer = 8;

// -------- THRESHOLD --------

int threshold = 100;

// -------- SENSOR VALUES --------

int s1, s2, s3, s4, s5, s6, s7, s8, s9;

void setup()

{

// Serial Monitor

Serial.begin(9600);

// HC-05 Bluetooth

Serial1.begin(9600);

// Buzzer

pinMode(buzzer, OUTPUT);

digitalWrite(buzzer, LOW);

}

void loop()

{

// -------- READ SENSORS --------

s1 = analogRead(fsr1);

s2 = analogRead(fsr2);

s3 = analogRead(fsr3);

s4 = analogRead(fsr4);

s5 = analogRead(fsr5);

s6 = analogRead(fsr6);

s7 = analogRead(fsr7);

s8 = analogRead(fsr8);

s9 = analogRead(fsr9);

// -------- LIMIT VALUES --------

// Converts readings into 1 digit only

// because your app expects 9 values exactly

s1 = map(s1, 0, 1023, 0, 9);

s2 = map(s2, 0, 1023, 0, 9);

s3 = map(s3, 0, 1023, 0, 9);

s4 = map(s4, 0, 1023, 0, 9);

s5 = map(s5, 0, 1023, 0, 9);

s6 = map(s6, 0, 1023, 0, 9);

s7 = map(s7, 0, 1023, 0, 9);

s8 = map(s8, 0, 1023, 0, 9);

s9 = map(s9, 0, 1023, 0, 9);

// -------- SEND DATA --------

// IMPORTANT:

// Your app splits empty text,

// so we send numbers WITHOUT commas

String data =

String(s1) +

String(s2) +

String(s3) +

String(s4) +

String(s5) +

String(s6) +

String(s7) +

String(s8) +

String(s9);

// Send to Bluetooth

Serial1.println(data);

// Serial Monitor

Serial.println(data);

// -------- BUZZER --------

if (

  s1 > 5 ||

  s2 > 5 ||

  s3 > 5 ||

  s4 > 5 ||

  s5 > 5 ||

  s6 > 5 ||

  s7 > 5 ||

  s8 > 5 ||

  s9 > 5

 )

{

digitalWrite(buzzer, HIGH);

}

else

{

digitalWrite(buzzer, LOW);

}

delay(500);

}

ABG · May 24, 2026, 7:49pm

A preliminary look shows you splitting at an empty (zero length) delimiter:

That has the effect of splitting at every character.
You get a macaroni necklace.

I know because the text cursor won't wiggle inside the supposedly blank text block.

Also, you fail to follow standard BlueTooth Delimiter advice:

Be sure to use println() at the end of each message to send from the sending device, to signal end of message.

Only use print() in the middle of a message.

Be sure not to println() in the middle of a message, or you will break it into two short messages and mess up the item count after you split the message in AI2.

Do not rely on timing for this, which is unreliable.

In the AI2 Designer, set the Delimiter attribute of the BlueTooth Client component to 10 to recognize the End of Line character.

Also, return data is not immediately available after sending a request,
you have to start a Clock Timer repeating and watch for its arrival in the Clock Timer event. The repeat rate of the Clock Timer should be faster than the transmission rate in the sending device, to not flood the AI2 buffers.

In your Clock Timer, you should check

  Is the BlueTooth Client still Connected?
  Is Bytes Available > 0?
     IF Bytes Available > 0 THEN
       set message var  to BT.ReceiveText(-1)

This takes advantage of a special case in the ReceiveText block:

ReceiveText(numberOfBytes)
Receive text from the connected Bluetooth device. If numberOfBytes is less than 0, read until a delimiter byte value is received.

If you are sending multiple data values per message separated by | or comma, have your message split into a local or global variable for inspection before trying to select list items from it. Test if (length of list(split list result) >= expected list length) before doing any select list item operations, to avoid taking a long walk on a short pier. This bulletproofing is necessary in case your sending device sneaks in some commentary messages with the data values.

Some people send temperature and humidity in separate messages with distinctive prefixes like "t:" (for temperature) and "h:" (for humidity).
(That's YAML format.)

The AI2 Charts component can recognize these and graph them. See Bluetooth Client Polling Rate - #12 by ABG

To receive YAML format messages, test if the incoming message contains ':' . If true, split it at ':' into a list variable, and find the prefix in item 1 and the value in item 2.

Here is a simple BlueTooth text receiver sample, for single value per line:

when Clock1 .Timer do1290×410 59.1 KB

when Screen1 .Initialize do814×182 22.9 KB

..

ABG · May 24, 2026, 7:54pm

Now that I have read your sketch, I see that you indeed split at single characters, so you lucked out on the empty string delimiter.

However, you still needed to use \n as your message delimiter.

So add a decimal 10 Delimiter in the Designer for your BlueTooth component, and ask for -1 bytes as the byte count when you read text to get exactly one message at a time.

Also, for bullet proofing, it is wise to check list length >= 9 before attempting list selects on your message.

Some one might have slipped some commentary messages into your data stream.