Home ADB Microbridge Android + Arduino + USB Host + Temperature + Light

Android + Arduino + USB Host + Temperature + Light

Posted by michael on May 2, 2012 in ADB Microbridge, Android, Arduino, Tutorials | 23 comments

Sensing temperature and light with Android and Arduino. This article will demonstrate a basic thermometer / ambient light level detection input accessory.

For additional background information on interfacing Android with the real world, check out my other introductory tutorials:

Simple Digital Input
Simple Digital Output
Simple Analog Input
Simple Analog Output

Hardware

Parts needed:

Android Device (1.6+)
Photocell
10K ohm resistor
TMP36 temperature sensor
Hook-up wire
Android ADK Board*
– OR –
Arduino compatible and USB Host shield

*Supported boards include:

Google ADK board, Freeduino ADK board , Seeed Studio ADK board, and DIY Drones ADK board

Assembly

Connect one of the photocell leads to 5v and the other to analog input pin A0. Also connect the same lead through a 10K resistor to ground. In hardware, this concept is known as a voltage divider. Then connect the ground and power leads of the TMP36 to, you guessed it, ground and 5V. Finally, connect the signal lead of the TMP36 to analog input pin A1. Here is a diagram of the completed circuit (created with Fritzing):

Software

Arduino Firmware

Next, upload the Arduino sketch to the microcontroller. The sketch uses the Microbridge implementation by Niels Brouwers. Microbridge uses Android Debug Bridge (ABD) forwarding over TCP, rather than the Google Android ADK. You can checkout the source for the Arduino sketch from Github, or just copy and paste the following into the Arduino IDE.

#include <SPI.h> #include <Adb.h> // Adb connection. Connection * connection; // Elapsed time for sensor sampling long lastTime; // Event handler for shell connection; called whenever data sent from Android to Microcontroller void adbEventHandler(Connection * connection, adb_eventType event, uint16_t length, uint8_t * data) { // Unused in this case } void setup() { Serial.begin(57600); // Record time for sensor polling timer lastTime = millis(); // Init the ADB subsystem. ADB::init(); // Open an ADB stream to the phone's shell. Auto-reconnect. Use port number 4568 connection = ADB::addConnection("tcp:4568", true, adbEventHandler); Serial.println("Ready!"); } void loop() { //Check if sensor should be sampled. if ((millis() - lastTime) > 20) { uint16_t data[2]; // light sensor data[0] = analogRead(A0); float celsius = getVoltage(1); //getting the voltage reading from the temp sensor celsius = (celsius - .5) * 100; //converting from 10 mv per degree wit 500 mV offset //to degrees ((volatge - 500mV) times 100) float fahrenheit = (celsius * (9.0 / 5.0)) + 32.0; data[1] = (int) fahrenheit; //Send the sensor value to Android as 4 bytes of data. connection->write(sizeof(data),(uint8_t*)&data); // Output debugging to serial Serial.println(data[0],DEC); Serial.println(data[1],DEC); // Update timer for sensor check lastTime = millis(); } // Poll the ADB subsystem. ADB::poll(); } float getVoltage(int pin){ return (analogRead(pin) * .004882814); //converting from a 0 to 1024 digital range // to 0 to 5 volts (each 1 reading equals ~ 5 millivolts }

Android App

The next step is to install the Android Demo application onto the device. You can either download the pre-built .apk or checkout the source from Github:

git clone git://github.com/mitchtech/android_adb_temp_light.git

Finally upload the app to the device (or browse to this page on the device and download the apk above). Connect the Android device to the USB Host board/shield, and start up the app.

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david demambro

Awesome, works great. Thanks, for this tutorial.
RBT

Hi this sketch when I go to my board tell me these errors occurred:
sketch_sep20a:20: error: stray ‘\’ in program
sketch_sep20a:20: error: stray ‘\’ in program
sketch_sep20a:21: error: stray ‘\’ in program
sketch_sep20a:21: error: stray ‘\’ in program
sketch_sep20a:26: error: stray ‘\’ in program
sketch_sep20a:32: error: stray ‘\’ in program
sketch_sep20a:0: error: variable or field ‘adbEventHandler’ declared void
sketch_sep20a:0: error: ‘Connection’ was not declared in this scope
sketch_sep20a:0: error: ‘connection’ was not declared in this scope
sketch_sep20a:0: error: expected primary-expression before ‘event’
sketch_sep20a:0: error: expected primary-expression before ‘length’
sketch_sep20a:0: error: expected primary-expression before ‘*’ token
sketch_sep20a:0: error: ‘data’ was not declared in this scope
sketch_sep20a:4: error: expected constructor, destructor, or type conversion before ‘*’ token
sketch_sep20a:8: error: variable or field ‘adbEventHandler’ declared void
sketch_sep20a:8: error: ‘Connection’ was not declared in this scope
sketch_sep20a:8: error: ‘connection’ was not declared in this scope
sketch_sep20a:8: error: expected primary-expression before ‘event’
sketch_sep20a:8: error: expected primary-expression before ‘length’
sketch_sep20a:8: error: expected primary-expression before ‘*’ token
sketch_sep20a:8: error: ‘data’ was not declared in this scope
sketch_sep20a.cpp: In function ‘void setup()’:
sketch_sep20a:18: error: ‘ADB’ has not been declared
sketch_sep20a:20: error: ‘connection’ was not declared in this scope
sketch_sep20a:20: error: ‘ADB’ has not been declared
sketch_sep20a:20: error: ‘u201ctcp’ was not declared in this scope
sketch_sep20a:20: error: ‘adbEventHandler’ was not declared in this scope
sketch_sep20a:21: error: ‘u201cReady’ was not declared in this scope
sketch_sep20a.cpp: In function ‘void loop()’:
sketch_sep20a:26: error: expected `)’ before ‘u2013′
sketch_sep20a:45: error: expected `)’ before ‘ADB’
How can I fix this?
- michael
  
  Copying and pasting the code directly from the website seemed to grab extra characters, so I have enclosed it within a github gist. It should now work correctly without stray ‘\’s now.
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Lemorlenny

You need to rewrite the entire line where the cursor error enlight, pheraps there some hidden char.
- michael
  
  That was indeed the issue, thanks for pointing out the easy fix!
RBT

Thanks, but I submit this sketch in the Arduino 1.0 and it found an error that say: Desktop\arduino-1.0s\libraries\Adb/Adb.h:20:20: error: wiring.h: No such file or directory, What can I do?
- lemorlenny
  
  You need to replace any occurence of
  #include
  with
  #include
  in *.h and *.cpp files.
- lemorlenny
  
  This editor have some problems in IE…
  I means:
  
  You need to replace any occurence of
  #include wiring.h to Arduino.h in all *.h and *.cpp files.
RBT

I don´t understand #iclude in*.h and*.cpp files.
RBT

I change the first name;

#include
#include

// Adb connection.
Connection * connection;

// Elapsed time for sensor sampling
long lastTime;

// Event handler for shell connection; called whenever data sent from Android to Microcontroller
void adbEventHandler(Connection * connection, adb_eventType event, uint16_t length, uint8_t * data)
{
// Unused in this case
}

void setup()
{
Serial.begin(57600);

// Record time for sensor polling timer
lastTime = millis();

// Init the ADB subsystem.
ADB::init();

// Open an ADB stream to the phone’s shell. Auto-reconnect. Use port number 4568
connection = ADB::addConnection(“tcp:4568”, true, adbEventHandler);

Serial.println(“Ready!”);
}

void loop()
{
//Check if sensor should be sampled.
if ((millis() – lastTime) > 20)
{
uint16_t data[2];
// light sensor
data[0] = analogRead(A0);
float celsius = getVoltage(1); //getting the voltage reading from the temp sensor
celsius = (celsius – .5) * 100; //converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge – 500mV) times 100)
float fahrenheit = (celsius * (9.0 / 5.0)) + 32.0;
data[1] = (int) fahrenheit;

//Send the sensor value to Android as 4 bytes of data.
connection->write(sizeof(data),(uint8_t*)&data);

// Output debugging to serial
Serial.println(data[0],DEC);
Serial.println(data[1],DEC);

// Update timer for sensor check
lastTime = millis();
}

// Poll the ADB subsystem.
ADB::poll();
}

float getVoltage(int pin){
return (analogRead(pin) * .004882814); //converting from a 0 to 1024 digital range
// to 0 to 5 volts (each 1 reading equals ~ 5 millivolts
}
- RBT
  
  #include
  #include
  
  // Adb connection.
  Connection * connection;
  
  // Elapsed time for sensor sampling
  long lastTime;
  
  // Event handler for shell connection; called whenever data sent from Android to Microcontroller
  void adbEventHandler(Connection * connection, adb_eventType event, uint16_t length, uint8_t * data)
  {
  // Unused in this case
  }
  
  void setup()
  {
  Serial.begin(57600);
  
  // Record time for sensor polling timer
  lastTime = millis();
  
  // Init the ADB subsystem.
  ADB::init();
  
  // Open an ADB stream to the phone’s shell. Auto-reconnect. Use port number 4568
  connection = ADB::addConnection(“tcp:4568”, true, adbEventHandler);
  
  Serial.println(“Ready!”);
  }
  
  void loop()
  {
  //Check if sensor should be sampled.
  if ((millis() – lastTime) > 20)
  {
  uint16_t data[2];
  // light sensor
  data[0] = analogRead(A0);
  float celsius = getVoltage(1); //getting the voltage reading from the temp sensor
  celsius = (celsius – .5) * 100; //converting from 10 mv per degree wit 500 mV offset
  //to degrees ((volatge – 500mV) times 100)
  float fahrenheit = (celsius * (9.0 / 5.0)) + 32.0;
  data[1] = (int) fahrenheit;
  
  //Send the sensor value to Android as 4 bytes of data.
  connection->write(sizeof(data),(uint8_t*)&data);
  
  // Output debugging to serial
  Serial.println(data[0],DEC);
  Serial.println(data[1],DEC);
  
  // Update timer for sensor check
  lastTime = millis();
  }
  
  // Poll the ADB subsystem.
  ADB::poll();
  }
  
  float getVoltage(int pin){
  return (analogRead(pin) * .004882814); //converting from a 0 to 1024 digital range
  // to 0 to 5 volts (each 1 reading equals ~ 5 millivolts
  }
RBT

Please, could you pass me the good sketch? because I don´t understand, that I have change in the sketch.
- lemorlenny
  
  I’m sorry but my first post was cut by editor.
  The last version of Arduino compiler use the file “Arduino.h” instead of “wiring.h” and wProgram.h files,so you need to substitute the line “#include wiring.h” and “#include wProgram.h” with the line “#include Arduino.h” in all occurrence of your sketch and in the other librarys used(file with .h and .cpp extension), if receive more error. Anyway you can see the error description at the bottom of the compiler window.
  - michael
    
    That is correct! This is an issue in the Arduino IDE 1.0+ (the article was written with 022 IDE). To fix the problem you will need to change the include statements in the Adb library, or others referenced (NOT in the sketch). This is located in the following files (which should be located in /path/to/sketchbook/libraries/):
    Adb.h, usb.cpp, and max3421e.cpp
    Change the each instance of:
    #include "wiring.h" and #include "wProgram.h"
    to
    #include "Arduino.h"
    in those files. If any others present an error in the compiler output at the bottom of the Arduino IDE when you compile, you will need to update those as well.
RBT

Thanks Michael, I submit the sketch in my board arduino mega adk, but when I connect the mobile phone Xperia Tipo in the board, the board not send the temperature and the light, also I istalled the app in my mobile. What can I do?
- michael
  
  Do you have USB debugging enabled on your Android device? On the device, go to Settings > Applications > Development and enable USB debugging (on an Android 4.0+ device, the setting is located in Settings > Developer options). Is there sufficient power to the board/device? Certain USB Host boards, such as this one from Sparkfun requires VIN on the Arduino, and cannot be powered directly through the USB port. It may also be beneficial to attempt it with a fully charged battery on the Android device, so it is not pulling too much current for the Arduino/USB Host to function correctly.
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andre

What kind of usb host shield here Im using usb host shield 2.0. is my usb shield compatible with this program?
Patrick Hochleitner

Hey could you explain to me why is it always required to do a voltage divider with the photo resistance? Its not the first time I see though I dont quite understand why do we need it.
sixpath

can i get your android project(full)?
anhtuan

i can’t find the adb.h file, where could i find it?
Alvaro Camara

It works perfectly but i’ve just one problem. When i connect my android device to arduino it charges itselve, but the battery keeps drowing… Is there any way i can supply enough power so it can charge correctly and i can keep the program working for a long time??
Thanks for your help
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Zhe Yang

what is the highest sampling rate for the light sensor？
Poornima Rao

do have the code for adk?

Android + Arduino + USB Host + Temperature + Light

Hardware

Parts needed:

Assembly

Software

Arduino Firmware

Android App

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Android + Arduino + USB Host + Temperature + Light

Hardware

Parts needed:

Assembly

Software

Arduino Firmware

Android App

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