Develop Reference

how to send and divide information into individual textview (Hc 05)

I am trying to make an application that connects to the arduino using the HC 05 module with three ultrasonic sensors. I was able to connect to the application and receive information from a particular sensor. But when I display the distance information of each sensor it is displayed in one text view (I would like three) but I have no idea what I could change in my code. Thanks in advance for your answer. Below I put the code in sequence: from arduino ideas, android studio app, android studio thread
int LtriggerPin = 13;
int LechoPin = 12;
int RtriggerPin = 11;
int RechoPin = 10;
int CtriggerPin = 9;
int CechoPin = 8;
int info = 0;
int state = 0;
void setup() {
Serial1.begin(9600);
pinMode(LtriggerPin, OUTPUT);
pinMode(LechoPin, INPUT);
pinMode(RtriggerPin, OUTPUT);
pinMode(RechoPin, INPUT);
pinMode(CtriggerPin, OUTPUT);
pinMode(CechoPin, INPUT);
}
void loop(){
sensor();
}
void sensor() {
int durationL, distanceL;
int durationR, distanceR;
int durationC, distanceC;
digitalWrite(LtriggerPin, HIGH);
delay(10);
digitalWrite(LtriggerPin, LOW);
durationL = pulseIn(LechoPin, HIGH);
distanceL = (durationL/2) / 29.1;
digitalWrite(RtriggerPin, HIGH);
delay(10);
digitalWrite(RtriggerPin, LOW);
durationR = pulseIn(RechoPin, HIGH);
distanceR = (durationR/2) / 29.1;
digitalWrite(CtriggerPin, HIGH);
delay(10);
digitalWrite(CtriggerPin, LOW);
durationC = pulseIn(CechoPin, HIGH);
distanceC = (durationC/2) / 29.1;
Serial1.print("Left Sensor ");
Serial1.print((String) distanceL + " cm" );
delay(500);
Serial1.println(" ");
Serial1.print("Right Sensor ");
Serial1.print((String) distanceR + " cm" );
delay(500);
Serial1.println(" ");
Serial1.print("Center Sensor ");
Serial1.print((String) distanceC + " cm" );
delay(500);
Serial1.println(" ");
Serial1.println(" ");
Serial1.println(" ");
}
//android thread
#Override
public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.available();
if(bytes != 0) {
buffer = new byte[1024];
SystemClock.sleep(100); //pause and wait for rest of data. Adjust this depending on your sending speed.
bytes = mmInStream.available(); // how many bytes are ready to be read?
bytes = mmInStream.read(buffer, 0, bytes); // record how many bytes we actually read
hesler.obtainMessage(MainActivity.MESSAGE_READ, bytes, -1, buffer)
.sendToTarget(); // Send the obtained bytes to the UI activity
}
} catch (IOException e) {
e.printStackTrace();
break;
}
}
}
public void write(String input) {
byte[] bytes = input.getBytes();
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
public void cancel() {
try {
sok.close();
} catch (IOException e) { }
}
// android Handler
handler = new Handler(Looper.getMainLooper()){
#Override
public void handleMessage(Message msg){
if(msg.what == MESSAGE_READ){
String readMessageL = null;
readMessageL = new String((byte[]) msg.obj, StandardCharsets.UTF_8);
TvC.setText(readMessageL);
}
if(msg.what == CONNECTING_STATUS){
char[] sConnected;
if(msg.arg1 == 1)
Tv3.setText(getString(R.string.BTConnected) + msg.obj);
else
Tv3.setText(getString(R.string.BTconnFail));
}
}
};

Reading temperature through DHT11 using Android Things

I am using Raspberry pi3 and DHT11 sensor for temperature monitoring project.
I have following pin positions
VCC to pin no : 2
Ground to pin no : 6
Output to GPIO : BCM22 i.e pin no 15
Code that I have used:
public class WeatherStationActivity extends Activity {
private Handler mHandler = new Handler();
private TextView mTxtStatus;
private PeripheralManagerService service = new PeripheralManagerService();
private Gpio tempGpio;
private int i = 0;
int[] dht11_dat = {0, 0, 0, 0, 0};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d("Weather station", "Started Weather Station");
setContentView(R.layout.activity_main);
mTxtStatus = (TextView) findViewById(R.id.txtStatus);
try {
tempGpio = service.openGpio("BCM22");
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if (i == 10) {
handler.removeCallbacks(this);
} else {
getTemp();
handler.postDelayed(this, 5000);
}
i++;
}
}, 5000);
} catch (Exception e) {
e.printStackTrace();
}
}
private void getTemp() {
boolean laststate = false;
try {
laststate = tempGpio.getValue();
} catch (IOException e) {
e.printStackTrace();
}
int j = 0;
final int MAXTIMINGS = 85;
dht11_dat[0] = dht11_dat[1] = dht11_dat[2] = dht11_dat[3] = dht11_dat[4] = 0;
try {
tempGpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW);
// tempGpio.setActiveType(Gpio.ACTIVE_LOW);
tempGpio.setValue(false);
// Thread.sleep(18);
TimeUnit.MILLISECONDS.sleep(18);
// tempGpio.setActiveType(Gpio.ACTIVE_HIGH);
// tempGpio.setActiveType(Gpio.ACTIVE_HIGH);
tempGpio.setValue(true);
TimeUnit.MICROSECONDS.sleep(40);
tempGpio.setDirection(Gpio.DIRECTION_IN);
/* tempGpio.setActiveType(Gpio.ACTIVE_HIGH);
tempGpio.setValue(true);*/
// tempGpio.setValue(true);
StringBuilder value = new StringBuilder();
for (int i = 0; i < MAXTIMINGS; i++) {
int counter = 0;
while (tempGpio.getValue() == laststate) {
counter++;
TimeUnit.MICROSECONDS.sleep(1);
if (counter == 255) {
break;
}
}
laststate = tempGpio.getValue();
mTxtStatus.append("\nLast State of Sensor " + laststate);
if (counter == 255) {
break;
}
//* ignore first 3 transitions *//*
if ((i >= 4) && (i % 2 == 0)) {
//* shove each bit into the storage bytes *//*
dht11_dat[j / 8] <<= 1;
if (counter > 16) {
dht11_dat[j / 8] |= 1;
}
j++;
}
}
// check we read 40 bits (8bit x 5 ) + verify checksum in the last
// byte
if ((j >= 40) && checkParity()) {
value.append(dht11_dat[2]).append(".").append(dht11_dat[3]);
Log.i("Logger", "temperature value readed: " + value.toString());
mTxtStatus.append("\nTemp " + value.toString());
} else {
mTxtStatus.append("\nNothing is working ");
Log.i("Logger", "Nothing is working ");
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (Exception ex) {
ex.printStackTrace();
}
}
private boolean checkParity() {
return dht11_dat[4] == (dht11_dat[0] + dht11_dat[1] + dht11_dat[2] + dht11_dat[3] & 0xFF);
}
}
Above code is giving me "Nothing is working" as output.
Any suggestion where I might be doing wrong?

You can't read data from DHT11 using Raspberry Pi 3 with Android Things because duration of DHT11 response pulses is from 26-28 us to 70 us, but max frequency of RP3 with AT GPIO is around 3kHz, which means around 300 us pulse duration. Take a look at answers to this question.

Android Bluetooth input stream not reading full array

I'm creating an app to read string values over Bluetooth serial port. My data receiving but in two parts. If I send $F00,A,B,0,M# via bluetooth it only reads $ in first part and F00,A,B,0,M# in next part. I provided my code here. Please do correct me if I'm wrong.
InputStream inputStream=null;
int avilableBytes=0;
public ConnectedThread(BluetoothSocket socket){
InputStream temp=null;
try{
temp=socket.getInputStream();
}catch (IOException e){
e.printStackTrace();
}
inputStream=temp;
}
public void run() {
try{
int bytes;
while (true){
try{
avilableBytes=inputStream.available();
if (avilableBytes>0){
byte[] buffer=new byte[avilableBytes];
bytes=inputStream.read(buffer);
final String readMessage=new String(buffer,0,bytes);
bt_handler.obtainMessage(handlerState,bytes,-1,readMessage).sendToTarget();
Log.d("PRAVEEN",readMessage);
}
}catch (IOException e){
e.printStackTrace();
}
}
}catch (Exception e){
e.printStackTrace();
}
}

Data are like stream bytes and can not be processed immediately when it comes with a few bytes. Data will not come all at once as a single packet. You have to use the other byte[] buffer (MainBuffer) in which you will gradually save incoming byte and move the index in that buffer. Then, from time to time (e.g. in the timer once per second) take data from the main buffer and processed it. By default you must implement some data frame with a separator (eg. Data * data * data * - Many ways to do it good or bad). I dealt with this in .net via Xamarin, but just as an example it may be helpfull :
update example, format
In ConnectedThread :
public override void Run()
{
while (true)
{
try
{
int readBytes = 0;
lock (InternaldataReadLock)
{
readBytes = clientSocketInStream.Read(InternaldataRead, 0, InternaldataRead.Length);
Array.Copy(InternaldataRead, TempdataRead, readBytes);
}
if (readBytes > 0)
{
lock (dataReadLock)
{
dataRead = new byte[readBytes];
for (int i = 0; i < readBytes; i++)
{
dataRead[i] = TempdataRead[i];
}
}
Bundle dataBundle = new Bundle();
dataBundle.PutByteArray("Data", dataRead);
Message message = btlManager.sourceHandler.ObtainMessage();
message.What = 1;
message.Data = dataBundle;
btlManager.sourceHandler.SendMessage(message);
}
}
catch (System.Exception e)
{
btlManager.btlState = BTLService.BTLState.Nothing;
}
}
}
In BTLHandler :
public override void HandleMessage(Message msg)
{
switch (msg.What)
{
case 1:
{
byte[] data = msg.Data != null ? msg.Data.GetByteArray("Data") : new byte[0];
btlService.BTLReceiveData(data);
}
break;
}
}
public void BTLReceiveData(byte[] data)
{
lock (dataReadLock)
{
for (int i = 0; i < data.Length; i++)
{
dataRead[dataReadWriteCursor] = data[i];
dataReadWriteCursor++;
}
}
}
In Timer :
int tmpWriteCursor = dataReadWriteCursor;
int tmpReadCursor = dataReadReadCursor;
lock (dataReadLock)
{
int newBytes = dataReadWriteCursor - dataReadReadCursor;
for (int i = 0; i < newBytes; i++)
{
dataReadMain[dataReadReadCursor] = dataRead[dataReadReadCursor++];
}
}
bool odradkovani = false;
string tmpRadek = "";
int lastLineIndex = 0;
List<string> list = new List<string>();
for (int i = LastWriteLineIndex; i < tmpWriteCursor; i++)
{
if (dataReadMain[i] >= 32 && dataReadMain[i] <= 255)
{
tmpRadek += (char)dataReadMain[i];
}
else if (dataReadMain[i] == 13) odradkovani = true;
else if (dataReadMain[i] == 10)
{
if (odradkovani)
{
odradkovani = false;
list.Add(Utils.GetFormatedDateTime(DateTime.Now) + " " + tmpRadek);
tmpRadek = "";
lastLineIndex = i + 1;
}
}
else
{
tmpRadek += "?" + dataReadMain[i].ToString() + "?";
}
}
WriteDataToLog(list);
LastWriteLineIndex = lastLineIndex;

GCM MultiCastResult Approach

This is my approach to use gcm for more than 1000 devices. Is it right that way? As I cannot try it unless I have more than 1000 users so any feedback would be appreciated and most importantly am I checking errors correctly? and updating database in a right way?
public class MessagingEndpoint {
private static final Logger log = Logger.getLogger(MessagingEndpoint.class.getName());
/**
* Api Keys can be obtained from the google cloud console
*/
private static final String API_KEY = System.getProperty("gcm.api.key");
private List<RegistrationRecord> records;
private List<String> getRegistrationId() {
records = ofy().load().type(RegistrationRecord.class).list();
List<String> records_ID = new ArrayList<String>();
for (int i = 0; i < records.size(); i++) {
records_ID.add(records.get(i).getRegId());
}
return records_ID;
}
private List<List<String>> regIdInThousands(List<String> list, final int L) {
List<List<String>> parts = new ArrayList<List<String>>();
final int N = list.size();
for (int i = 0; i < N; i += L) {
parts.add(new ArrayList<String>(list.subList(i, Math.min(N, i + L))));
}
return parts;
}
*
* #param message The message to send
*/
public void sendMessage(#Named("message") String message) throws IOException {
if (message == null || message.trim().length() == 0) {
log.warning("Not sending message because it is empty");
return;
}
// crop longer messages
if (message.length() > 1000) {
message = message.substring(0, 1000) + "[...]";
}
Sender sender = new Sender(API_KEY);
Message msg = new Message.Builder().addData("message", message).build();
List<List<String>> regIdsParts = regIdInThousands(getRegistrationId(), 1000);
for (int i = 0; i < regIdsParts.size(); i++) {
MulticastResult multicastResult = sender.send(msg, regIdsParts.get(i), 5);
if (multicastResult.getCanonicalIds() != 0) {
List<Result> results = multicastResult.getResults();
for (int j = 0; j < results.size(); j++) {
if (results.get(j).getMessageId() != null) {
log.info("Message sent to " + regIdsParts.get(i).get(j));
String canonicalRegId = results.get(j).getCanonicalRegistrationId();
if (canonicalRegId != null) {
// if the regId changed, we have to update the datastore
log.info("Registration Id changed for " + regIdsParts.get(i).get(j) + " updating to " + canonicalRegId);
regIdsParts.get(i).set(j, canonicalRegId);
ofy().save().entity(records.get((i*1000)+j)).now();
} else {
String error = results.get(j).getErrorCodeName();
if (error.equals(Constants.ERROR_NOT_REGISTERED)) {
log.warning("Registration Id " + regIdsParts.get(i).get(j) + " no longer registered with GCM, removing from datastore");
// if the device is no longer registered with Gcm, remove it from the datastore
ofy().delete().entity(records.get((i*1000)+j)).now();
} else {
log.warning("Error when sending message : " + error);
}
}
}
}
}
}
}
}

Your code looks good, Only thing I can notice is its quite verbose and complicated. You can take a look at this one just as a option if you are considerate about error handling:
public void sendMessageToMultipleDevices(String key, String value, ArrayList devices) {
Sender sender = new Sender(myApiKey);
Message message = new Message.Builder().addData(key, value).build();
try {
MulticastResult result = sender.send(message, devices, 5);
MTLog.info(TAG, "result " + result.toString());
for (int i = 0; i < result.getTotal(); i++) {
Result r = result.getResults().get(i);
if (r.getMessageId() != null) {
String canonicalRegId = r.getCanonicalRegistrationId();
if (canonicalRegId != null) {
// devices.get(i) has more than on registration ID: update database
}
} else {
String error = r.getErrorCodeName();
if (error.equals(Constants.ERROR_NOT_REGISTERED)) {
// application has been removed from devices.get(i) - unregister database
}
}
}
} catch (IOException ex) {
MTLog.err(TAG, "sending message failed", ex);
}
}

Retrieving Android BluetoothLE device information (Major / minor / identifier / ProximityUUID) on scan?

I've been looking around and unfortunately the android ibeacon library has been deprecated, so I am attempting to do this native. I have implemented the BluetoothAdapter.LeScanCallback and the built in onLeScan() method that will fire when a device is picked up. I would like to read in that device's ProximityUUID, major and minor characteristics and identifier. I'm not sure how to get that information out of the Android object BluetoothDevice.
How do I extract that information (ProximityUUID, major, minor, & identifier characteristics) from the Android BluetoothDevice, or is there another way to do it?
Thanks!

you can refer this post to fully understand what those bytes means in LeScanCallback .
And this is my code to parse all information needed:
// an object with all information embedded from LeScanCallback data
public class ScannedBleDevice implements Serializable {
// public BluetoothDevice BLEDevice;
/**
* Returns the hardware address of this BluetoothDevice.
* <p>
* For example, "00:11:22:AA:BB:CC".
*
* #return Bluetooth hardware address as string
*/
public String MacAddress;
public String DeviceName;
public double RSSI;
public double Distance;
public byte[] CompanyId;
public byte[] IbeaconProximityUUID;
public byte[] Major;
public byte[] Minor;
public byte Tx;
public long ScannedTime;
}
// use this method to parse those bytes and turn to an object which defined proceeding.
// the uuidMatcher works as a UUID filter, put null if you want parse any BLE advertising data around.
private ScannedBleDevice ParseRawScanRecord(BluetoothDevice device,
int rssi, byte[] advertisedData, byte[] uuidMatcher) {
try {
ScannedBleDevice parsedObj = new ScannedBleDevice();
// parsedObj.BLEDevice = device;
parsedObj.DeviceName = device.getName();
parsedObj.MacAddress = device.getAddress();
parsedObj.RSSI = rssi;
List<UUID> uuids = new ArrayList<UUID>();
int skippedByteCount = advertisedData[0];
int magicStartIndex = skippedByteCount + 1;
int magicEndIndex = magicStartIndex
+ advertisedData[magicStartIndex] + 1;
ArrayList<Byte> magic = new ArrayList<Byte>();
for (int i = magicStartIndex; i < magicEndIndex; i++) {
magic.add(advertisedData[i]);
}
byte[] companyId = new byte[2];
companyId[0] = magic.get(2);
companyId[1] = magic.get(3);
parsedObj.CompanyId = companyId;
byte[] ibeaconProximityUUID = new byte[16];
for (int i = 0; i < 16; i++) {
ibeaconProximityUUID[i] = magic.get(i + 6);
}
if (uuidMatcher != null) {
if (ibeaconProximityUUID.length != uuidMatcher.length) {
Log.e(LOG_TAG,
"Scanned UUID: "
+ Util.BytesToHexString(
ibeaconProximityUUID, " ")
+ " filtered by UUID Matcher "
+ Util.BytesToHexString(uuidMatcher, " ")
+ " with length requirment.");
return null;
}
for (int i = 0; i < 16; i++) {
if (ibeaconProximityUUID[i] != uuidMatcher[i]) {
Log.e(LOG_TAG,
"Scanned UUID: "
+ Util.BytesToHexString(
ibeaconProximityUUID, " ")
+ " filtered by UUID Matcher "
+ Util.BytesToHexString(uuidMatcher,
" "));
return null;
}
}
}
parsedObj.IbeaconProximityUUID = ibeaconProximityUUID;
byte[] major = new byte[2];
major[0] = magic.get(22);
major[1] = magic.get(23);
parsedObj.Major = major;
byte[] minor = new byte[2];
minor[0] = magic.get(24);
minor[1] = magic.get(25);
parsedObj.Minor = minor;
byte tx = 0;
tx = magic.get(26);
parsedObj.Tx = tx;
parsedObj.ScannedTime = new Date().getTime();
return parsedObj;
} catch (Exception ex) {
Log.e(LOG_TAG, "skip one unknow format data...");
// Log.e(LOG_TAG,
// "Exception in ParseRawScanRecord with advertisedData: "
// + Util.BytesToHexString(advertisedData, " ")
// + ", detail: " + ex.getMessage());
return null;
}
}

Payloads of advertising packets should be parsed as a list of AD structures.
iBeacon is a kind of AD structures.
See "iBeacon as a kind of AD structures" for details. Also, see an answer to a similar question.