Converting 4 Bytes To Integer - MIT App Inventor Help Home » Arduino Convert 4 Bytes To Int » Converting 4 Bytes To Integer - MIT App Inventor Help Maybe your like Arduino Convert Decimal A Hexadecimal Arduino Convert Decimal To Bcd Arduino Convert Uint8_t To String Arduino Cw Decoder Kit Arduino Cw Decoder Wb7fhc Loading Converting 4 bytes to integer MIT App Inventor Help Theodorkkbs October 2, 2020, 8:15am 1 yet another post , this time for a different problem . I am connecting my phone app with my Arduino which works as a server and transmits sensor values to the phone. I want to get the integers from arduino to phone and upload them from phone to ioT platform. Everything is fine so far and i can upload values but they are all 0 . I checked that BLE reads these values from arduino as bytes , and sends them to phone as 4 bytes. My problem is i need to convert these 4 bytes to an integer and then send it to iot platform. in c++ you would need something like int buffToInteger(char * buffer) { int a = int((unsigned char)(buffer[0]) << 24 | (unsigned char)(buffer[1]) << 16 | (unsigned char)(buffer[2]) << 8 | (unsigned char)(buffer[3])); return a; } but i have no clue how to convert it Here Ps. unsigned because i know there are positive values 1 Like Kumaraswamy October 2, 2020, 8:29am 2 import java.util.Arrays; public String GetBytesA(String input) { byte[] byt = input.getBytes(); return Arrays.toString(byt); } @SimpleFunction(description = "Convert string to bytes") public String GetBytes(String input) { return GetBytesA(input); } Can be done through extension Theodorkkbs October 2, 2020, 10:58am 4 I need to convert Bytes to integer ot string to bytes . Also i cant find the extension you are talking , could you provide a link ? 1 Like ChrisWard October 2, 2020, 11:44am 5 Send the values as strings from Arduino, App Inventor can collect them as strings and process them as integers. 2 Likes Theodorkkbs October 2, 2020, 1:28pm 6 I converted the int to a char array and i send it to app via BLE , then i use this block to read it and upload it . image1146×577 31.2 KB My test label on my phone shows i receive this value 120780253_363913868071834_768841630051365127_n1150×1682 212 KB Really i dont know whats going on 1 Like ChrisWard October 2, 2020, 1:43pm 7 Looks like the data packet is not being assembled correctly in the Arduino Script. 1 Like Theodorkkbs October 2, 2020, 1:44pm 8 or does it get transformed wrong in BLE server ? 1 Like ChrisWard October 2, 2020, 2:24pm 9 There is no transforming 1 Like Theodorkkbs October 2, 2020, 2:25pm 10 Transforming in a way like , Firstly i was sending int to BLE and BLe was giving me Hex values . Could char array be converted to something in ble ? thats what i meant 1 Like ChrisWard October 2, 2020, 2:30pm 11 Post your Arduino Sketch as a .txt file for me to take a quick look. Looking at your 'StringsReceived' Block, if the Thingspeak_List is initialized as an actual Blocks List, the data packet values need to be split into this List. You also will not see a List correctly in a Label by just plugging it in, you have to feed or assemble the data in value-by-value. 1 Like Theodorkkbs October 2, 2020, 3:01pm 13 I pm'd The sketch . Do i need a text with a comma to seperate a block lists value ? 1 Like ChrisWard October 2, 2020, 4:31pm 14 Theodorkkbs: Do i need a text with a comma to seperate a block lists value ? Only if that is the separator used by the Sketch. Theodorkkbs: I pm'd The sketch Is it a top secret military document or something? We prefer everything to be in the open so that others can learn too. That's one of the expediences when the Software and the Tech Support are free. 1 Like Theodorkkbs October 2, 2020, 4:33pm 15 u are right . sketch.txt (2.7 KB) heres the sketch , i tried with dtostrf but i think it needs a lib i dont have in order to happen , cuz i get compiler error so i tried itoa for convertsion 1 Like ABG October 2, 2020, 4:36pm 16 Don't be shy ... /* */ #include <ArduinoBLE.h> #define SERVICE_UUID #define CHARACTERISTIC_UUID_TX #define SENSOR_PIN A0 #define LO_PLUS_PIN 10 #define LO_PLUS_MIN 11 BLEService ECGservice(SERVICE_UUID ); BLEIntCharacteristic ECGchar( CHARACTERISTIC_UUID_TX, BLERead | BLENotify ); int EcgValue = 0; static unsigned long previousMillis = 0; void setup() { Serial.begin(9600); // initialize serial communication pinMode(LO_PLUS_PIN, INPUT); // Setup for leads off detection LO + pinMode(LO_PLUS_MIN, INPUT); // Setup for leads off detection LO - while (!Serial); // begin initialization if (!BLE.begin()) { Serial.println("starting BLE failed!"); while (1); } /* Set a local name for the BLE device This name will appear in advertising packets and can be used by remote devices to identify this BLE device The name can be changed but maybe be truncated based on space left in advertisement packet */ BLE.setLocalName("Ecg Rose"); BLE.setAdvertisedService(ECGservice); // add the service UUID ECGservice.addCharacteristic(ECGchar); // add the ecg characteristic BLE.addService(ECGservice); // Add the battery service ECGchar.writeValue( 0 ); // set initial value for this characteristic /* Start advertising BLE. It will start continuously transmitting BLE advertising packets and will be visible to remote BLE central devices until it receives a new connection */ // start advertising BLE.advertise(); Serial.println("Bluetooth device active, waiting for connections..."); } void loop() { // wait for a BLE central BLEDevice central = BLE.central(); // if a central is connected to the peripheral: if (central) { Serial.print("Connected to central: "); // print the central's BT address: Serial.println(central.address()); // turn on the LED to indicate the connection: // while the central is connected: while (central.connected()) { EcgValue = analogRead(SENSOR_PIN); long currentMillis = millis(); // Let's convert the value to a char array: char txString[4]; // make sure this is big enuffz // dtostrf(EcgValue, 1, 2, txString); // int_val, min_width, digits_after_decimal, char_buffer it needs Library , doesnt read it itoa(EcgValue, txString, 10); if (currentMillis - previousMillis >= 200) { previousMillis = currentMillis; ECGchar.writeValue((int)txString); Serial.println(txString); } } // when the central disconnects, turn off the LED: Serial.print("Disconnected from central: "); Serial.println(central.address()); } } 1 Like Theodorkkbs October 2, 2020, 4:39pm 17 I really dont know whats up with me today 1 Like ChrisWard October 2, 2020, 4:44pm 18 Where did you find this Sketch? It's a bit of a mess. Apart from the Phone (App), is there another device receiving data? What is the expected range of the EcgValue? 1 Like Theodorkkbs October 2, 2020, 4:47pm 19 Its the ble example and i added characteristic for Read notify and the Ecg value to read A0 and the conversion it doesnt go higher than 1200 when i tested and the loop needs an auto format and delete the extra spaces i did to make it more clear when i was writing 1 Like ChrisWard October 2, 2020, 4:47pm 20 ... and you are in fact only sending the EcgValue, every 200 millis, so we do not need a value separator..... 1 Like Theodorkkbs October 2, 2020, 4:48pm 21 Yes i did that to give time for BLe to read, Sketch is to sent ECG value only , everything else should be on the app 1 Like ChrisWard October 2, 2020, 5:04pm 22 I notice for example that UUIDs are there - but are they being used? 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