Android device - Can't read message from Arduino

Hello there,

I'm trying to create an app that will be able to communicate with some Arduinos via USB on an Android device. For that, i'm using the Physicaloid library to communicate with the serial port. I managed to send messages to the Arduino (like if the arduino gets the message "on", it turns on a LED), but when it's time to send a string from Arduino to the Android device, things are going a bit weird. For example, when I send "Hello there", sometime I receive "llo there", other times "Hello th" or maybe "llo th". It's a bit random but something is certain, I can't receive the entire message.

PS: I made an Android plugin for that.

Here are the scripts I'm using.

/* -------------------------------------------------------------------*/
Arduino:

#define HELLO "hello\r\n"
#define GOODBYE "goodbye\r\n"
#define ANSWER "oh, Hi !"

#define LED 13

void setup() {
pinMode(LED, OUTPUT);

Serial.begin(9600);
Serial.setTimeout(100);
}

void loop() {
if (Serial.available() > 0){

Serial.flush();
String message = Serial.readString();

if (message.equals(HELLO)) {
digitalWrite(LED, HIGH);
Serial.print(ANSWER);
} else if (message.equals(GOODBYE)) {
digitalWrite(LED, LOW);
}
}
}

/* -------------------------------------------------------------------*/

Java :

package com.anthonyferry.myplugin;

import android.content.Context;
import com.physicaloid.lib.Physicaloid;
import com.physicaloid.lib.usb.driver.uart.ReadLisener;
import java.io.UnsupportedEncodingException;

public class SerialPortCommunicator {

static Physicaloid _physicaloid;
static Context _context;
static String message;

public static void initialize(Context context, int baudRate){
_context = context;
_physicaloid = new Physicaloid(context);
_physicaloid.setBaudrate(baudRate);
}

public static boolean open(){
if(_physicaloid.open()) {

// When we get a message from Arduino
_physicaloid.addReadListener(new ReadLisener() {

String readStr;

@override
public void onRead(int size) {
byte[] buf = new byte[size];
_physicaloid.read(buf, size);

try {
readStr = new String(buf, "UTF-8");
} catch (UnsupportedEncodingException e) {
message = e.getMessage();
return;
}
message = readStr;
}
});
return true;
}
return false;
}

public static boolean close() {
_physicaloid.clearReadListener();
return _physicaloid.close();
}

public static boolean isOpen() {
return _physicaloid.isOpened();
}

public static String getMessage() {
return message;
}

public static void sendMessage(String message){

if (_physicaloid.isOpened()) {
if (message.length() > 0){
byte[] buf = message.getBytes();
_physicaloid.write(buf, buf.length);
}
}
}
}

/* -------------------------------------------------------------------*/

C# Unity to manage Arduino java plugin :

Code (CSharp):

1. // This is the script to manage the Arduino
2.  
3. using System.Collections;
4. using System.Collections.Generic;
5. using UnityEngine;
6.  
7. public class Arduino : MonoBehaviour {
8.  
9.     int baudRate = 9600;
10.  
11.     AndroidJavaClass unityPlayer;
12.     AndroidJavaClass arduinoPort;
13.     AndroidJavaObject context;
14.  
15.     static Arduino _instance;
16.     public static Arduino instance { get { return _instance; } }
17.  
18.     bool _initialized = false;
19.     public bool initialized { get { return _initialized; } }
20.  
21.     void Awake() {
22.         _instance = this;
23.     }
24.  
25.     public void Initialize()
26.     {
27.         // Get the activity context
28.         unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
29.         context = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
30.  
31.         // Get the correct android plugin
32.         arduinoPort = new AndroidJavaClass("com.anthonyferry.myplugin.SerialPortCommunicator");
33.         arduinoPort.CallStatic("initialize", new object[2] { context, baudRate });
34.     }
35.  
36.     public bool IsOpen { get { return arduinoPort.CallStatic<bool>("isOpen"); } }
37.  
38.     public bool Open() {
39.         return arduinoPort.CallStatic<bool>("open");
40.     }
41.  
42.     public bool Close() {
43.         return arduinoPort.CallStatic<bool>("close");
44.     }
45.  
46.     public void Write(string message) {
47.         arduinoPort.CallStatic("sendMessage", message + '\r' + '\n');
48.     }
49.  
50.     public string Read() {
51.         return arduinoPort.CallStatic<string>("getMessage");
52.     }
53. }
54.  

/*-----------------------------------------------------------*/

C# Unity to use with UI

Code (CSharp):

1. using System.Collections;
2. using System.Threading;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.UI;
6.  
7. public class TestScript : MonoBehaviour {
8.  
9.     public class BoolMonitor
10.     {
11.         public delegate bool BoolGenerator();
12.  
13.         private string m_name = "";
14.         private BoolGenerator m_generator;
15.         private bool m_prevValue = false;
16.         private bool m_currentValue = false;
17.         private bool m_currentValueRecentlyChanged = false;
18.         private float m_displayTimeout = 0.0f;
19.         private float m_displayTimer = 0.0f;
20.  
21.         public string value
22.         {
23.             get
24.             {
25.                 string msg = m_name;
26.  
27.                 if (m_currentValue && m_currentValueRecentlyChanged)
28.                     msg += ": *True*\n";
29.                 else if (m_currentValue)
30.                     msg += ":  True \n";
31.                 else if (!m_currentValue && m_currentValueRecentlyChanged)
32.                     msg += ":  False \n";
33.                 else if (!m_currentValue)
34.                     msg += ":  False \n";
35.  
36.                 return msg;
37.             }
38.         }
39.  
40.         public BoolMonitor(string name, BoolGenerator generator, float displayTimeout = 0.5f)
41.         {
42.             m_name = name;
43.             m_generator = generator;
44.             m_displayTimeout = displayTimeout;
45.         }
46.  
47.         public void Update()
48.         {
49.             m_prevValue = m_currentValue;
50.             m_currentValue = m_generator();
51.  
52.             if (m_currentValue != m_prevValue)
53.             {
54.                 m_currentValueRecentlyChanged = true;
55.                 m_displayTimer = m_displayTimeout;
56.             }
57.  
58.             if (m_displayTimer > 0.0f)
59.             {
60.                 m_displayTimer -= Time.deltaTime;
61.  
62.                 if (m_displayTimer <= 0.0f)
63.                 {
64.                     m_currentValueRecentlyChanged = false;
65.                     m_displayTimer = 0.0f;
66.                 }
67.             }
68.         }
69.     }
70.  
71.     public Text debugText;
72.     public Text answerText;
73.     public string messageOn;
74.     public string messageOff;
75.     public string answer = "pong";
76.  
77.     bool isConnected;
78.     public bool IsConnected
79.     {
80.         get
81.         {
82.             return isConnected;
83.         }
84.  
85.         set
86.         {
87.             isConnected = value;
88.         }
89.     }
90.  
91.     bool isCoroutineRunning;
92.     public bool IsCoroutineRunning
93.     {
94.         get
95.         {
96.             return isCoroutineRunning;
97.         }
98.  
99.         set
100.         {
101.             isCoroutineRunning = value;
102.         }
103.     }
104.    
105.     List<BoolMonitor> monitors;
106.  
107.     // Buttons' functions
108.     public void InitArduino() { Arduino.instance.Initialize(); }
109.     public void OpenArduino() { Arduino.instance.Open(); }
110.     public void CloseArduino() { Arduino.instance.Close(); }
111.     public void ReadArduino() { answerText.text = Arduino.instance.Read() == null ? "no answers" : Arduino.instance.Read(); }
112.     public void TurnOn() { Arduino.instance.Write(messageOn); }
113.     public void TurnOff() { Arduino.instance.Write(messageOff); }
114.  
115.     void Start()
116.     {
117.         monitors = new List<BoolMonitor>()
118.         {
119.             new BoolMonitor("isOpen", () => Arduino.instance.IsOpen),
120.             new BoolMonitor("isConnected", () => IsConnected),
121.             new BoolMonitor("isCoroutineRunning", () => IsCoroutineRunning)
122.         };
123.  
124.     }
125.  
126.     void Update()
127.     {
128.         string data = "";
129.  
130.         foreach (BoolMonitor monitor in monitors)
131.         {
132.             monitor.Update();
133.             data += monitor.value;
134.         }
135.  
136.         debugText.text = data;
137.     }
138. }

The logic of this program is the following :

I send a message to Arduino.
The arduino turn on the LED.
The arduino send back another message.
[problem] Can't read the message properly

 

Nobody can help me ? Please =) Or maybe this thread is not in the good forum ?

 

Hello AnthonyFerryDG.
Have you found a solution? I follow your step and same result... i have truncate response from arduino... I start looking in the buffer system of physicaloid, but i don't see what is going wrong...
Thank you !

 

JeffDUnity3d, thank you, but i have a spécial case where (for some people) setting up a wifi is more difficult than plug a usb cable

 

So i try to change the buffer size or the thread pause time of 50 ms but all my try where worst than default settings...
I have to look for offset, because some time it's ok, but 5 time latter, the message is randomly troncated, like o wrong offset...

 

ok my setup is, one samsung galaxy tab A 7" or one Archos 70 Oxygen, for arduino i test with one DUE or one UNO.
Unity with the above script, arduino with the above script, and two jar files as unity plugin ( the java script above and the physicaloid library).
With the samsung or the archos tablet same result, with the arduino DUE or UNO same result,
The DUE working with UartCdcAcm driver and the UNO work with the UartCH340 driver. So i keep the DUE for testing and only look at the UartCdcAcm driver.
From my log the problem is from mConnection.bulkTransfer(mEndpointIn, rbuf, rbuf.length, 50); in UartCdcAcm.java file.
In this reading loop i already have truncated message.
i have to understand bulkTransfer...and the RingBuffer

 

so, i test in c# in unity to trim the message + i put a starting and ending character from arduino (to keep the message from start to end). I manage to get the string in the right order and all is good !

 

Hello there,

I did some Andoird apps with the PhysicaloidLibrary. And all works fine.

I want to do the same as you. But I have no luck.
I use the Android Studio to create a plugin for Unity.
Everything is well and I can access the library.
But I get no connection to the USB.

In your Android.cs, the line 33 seems not to work at me. Maybe a version modification.

Code (CSharp):

1. arduinoPort.CallStatic("initialize", new object[2] { context, baudRate });

I have to write it so:

Code (CSharp):

1. arduinoPort.CallStatic("initialize", context, baudRate);

I use the same code that you posted above.

How did you make your plugin?
Do you have a tutorial about your work?

 

Hello,

I'm getting Gradle build errors in Unity when i try to build an App in Unity.


CommandInvokationFailure: Gradle build failed.
/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/bin/java -classpath "/Applications/Unity/PlaybackEngines/AndroidPlayer/Tools/gradle/lib/gradle-launcher-4.2.1.jar" org.gradle.launcher.GradleMain "-Dorg.gradle.jvmargs=-Xmx4096m" "assembleRelease"

stderr[
/Users/UgoOdukwe/Desktop files/some ish/ArduinoTest/Temp/gradleOut/src/main/java/com/anthonyferry/myplugin/SerialPortCommunicator.java:4: error: package com.physicaloid.lib does not exist
import com.physicaloid.lib.Physicaloid;
^
/Users/UgoOdukwe/Desktop files/some ish/ArduinoTest/Temp/gradleOut/src/main/java/com/anthonyferry/myplugin/SerialPortCommunicator.java:5: error: package com.physicaloid.lib.usb.driver.uart does not exist
import com.physicaloid.lib.usb.driver.uart.ReadLisener;
^
/Users/UgoOdukwe/Desktop files/some ish/ArduinoTest/Temp/gradleOut/src/main/java/com/anthonyferry/myplugin/SerialPortCommunicator.java:10: error: cannot find symbol
static Physicaloid _physicaloid;
^
symbol: class Physicaloid
location: class SerialPortCommunicator
/Users/UgoOdukwe/Desktop files/some ish/ArduinoTest/Temp/gradleOut/src/main/java/com/anthonyferry/myplugin/SerialPortCommunicator.java:16: error: cannot find symbol
_physicaloid = new Physicaloid(context);
^
symbol: class Physicaloid
location: class SerialPortCommunicator
/Users/UgoOdukwe/Desktop files/some ish/ArduinoTest/Temp/gradleOut/src/main/java/com/anthonyferry/myplugin/SerialPortCommunicator.java:24: error: cannot find symbol
_physicaloid.addReadListener(new ReadLisener() {
^
symbol: class ReadLisener
location: class SerialPortCommunicator
5 errors

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileReleaseJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

* Get more help at https://help.gradle.org

BUILD FAILED in 2s
]
stdout[
reBuild UP-TO-DATE
reReleaseBuild UP-TO-DATE
:compileReleaseAidl UP-TO-DATE
:compileReleaseRenderscript UP-TO-DATE
:checkReleaseManifest UP-TO-DATE
:generateReleaseBuildConfig UP-TO-DATE
repareLintJar UP-TO-DATE
:generateReleaseResValues UP-TO-DATE
:generateReleaseResources UP-TO-DATE
:mergeReleaseResources UP-TO-DATE
:createReleaseCompatibleScreenManifests UP-TO-DATE
rocessReleaseManifest
:splitsDiscoveryTaskRelease UP-TO-DATE
rocessReleaseResources
:generateReleaseSources
:javaPreCompileRelease UP-TO-DATE
:compileReleaseJavaWithJavac FAILED
14 actionable tasks: 3 executed, 11 up-to-date
]
exit code: 1
UnityEditor.Android.Command.WaitForProgramToRun (UnityEditor.Utils.Program p, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidJavaTools.RunJava (System.String args, System.String workingdir, System.Action`1 progress, System.String error)
UnityEditor.Android.GradleWrapper.Run (UnityEditor.Android.AndroidJavaTools javaTools, System.String workingdir, System.String task, System.Action`1 progress)
Rethrow as GradleInvokationException: Gradle build failed
UnityEditor.Android.GradleWrapper.Run (UnityEditor.Android.AndroidJavaTools javaTools, System.String workingdir, System.String task, System.Action`1 progress)
UnityEditor.Android.PostProcessor.Tasks.BuildGradleProject.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)

 

In my blog I have started a series of articles on this topic. Here is the first:

https://www.lmdsmart.com/2019/06/conectar-arduino-unity-android-por-usb.html

En un artículo posterior pondré mi plugin.