Android + Arduino + USB Host + Simple Analog Input

May 2nd, 2012 by michael

0
  This worked for me.

Simplest possible analog input with the ADK.  This article will discuss the bare minimal requirements for development of a basic USB input accessory.  The goal is to demonstrate the easiest possible use of the technology.  For additional background information on Android development, Arduino, and MicroBridge, check out these links:

Android Developer’s Guide

Getting Started with Arduino

Microbridge

 

Getting Started

First, make sure you have setup the development environments for Arduino and Android:

Arduino IDE

Android SDK

 

Hardware

Parts needed:

  • Android Device (1.6+)
  • Photocell
  • 10K ohm resistor
  • 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.  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 Microbridgeimplementation 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>

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()
{
  // 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);  
}

void loop()
{
  //Check if sensor should be sampled.
  if ((millis() - lastTime) > 20)
  {
    uint16_t data = analogRead(A0);

    //Send the sensor value to Android as two bytes of data.
    connection->write(2,(uint8_t*)&data);

    Serial.println(data,DEC);   // Output debugging to serial

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

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

 

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_simple_analog_input.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.

 

Posted in ADB Microbridge, Android, Arduino, Tutorials | 13 comments

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13 comments on this post.

  1. Android + Arduino + USB Host + Sensor Graph | MitchTech:

    June 28th, 2012 at 2:47 am

    [...] Digital Input Simple Digital Output Simple Analog Input Simple Analog [...]

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    June 28th, 2012 at 2:48 am

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    June 28th, 2012 at 2:50 am

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    June 28th, 2012 at 2:51 am

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    June 28th, 2012 at 2:52 am

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  6. kyle kim:

    October 13th, 2012 at 3:56 am

    this source comes up error message… plz help me

  7. kyle:

    October 13th, 2012 at 4:20 am

    ADB_Simple_Analog_Input.pde:-1: error: variable or field ‘adbEventHandler’ declared void
    ADB_Simple_Analog_Input.pde:-1: error: ‘adb_eventType’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: expected primary-expression before ‘length’
    ADB_Simple_Analog_Input.pde:-1: error: expected constructor, destructor, or type conversion before ‘long’
    ADB_Simple_Analog_Input.pde:-1: error: variable or field ‘adbEventHandler’ declared void
    ADB_Simple_Analog_Input.pde:-1: error: ‘adb_eventType’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: expected primary-expression before ‘length’
    ADB_Simple_Analog_Input.cpp: In function ‘void setup()’:
    ADB_Simple_Analog_Input.pde:-1: error: ‘lastTime’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: ‘ADB’ has not been declared
    ADB_Simple_Analog_Input.pde:-1: error: ‘connection’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: ‘ADB’ has not been declared
    ADB_Simple_Analog_Input.pde:-1: error: ‘adbEventHandler’ was not declared in this scope
    ADB_Simple_Analog_Input.cpp: In function ‘void loop()’:
    ADB_Simple_Analog_Input.pde:-1: error: ‘lastTime’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: ‘connection’ was not declared in this scope
    ADB_Simple_Analog_Input.pde:-1: error: ‘ADB’ has not been declared

  8. Android + Arduino + USB Host + Pan Tilt LEDs | MitchTech:

    October 22nd, 2012 at 1:29 pm

    [...] Digital Input Simple Digital Output Simple Analog Input Simple Analog [...]

  9. Android + Arduino + USB Host + Combination Lock | MitchTech:

    October 22nd, 2012 at 1:36 pm

    [...] Digital Input Simple Digital Output Simple Analog Input Simple Analog [...]

  10. michael:

    October 22nd, 2012 at 1:46 pm

    Hi Kyle, have you installed the Microbridge library? If not, you will need to download the Adb library here and unpack it into the libraries directory of your Arduino installation as described in the Getting Started guide for Microbridge.

  11. kyle:

    November 4th, 2012 at 7:15 am

    hi~~
    Thanks to your help, I solved this problem.
    but i have one more problem….
    After uploading cell phone and tried to connect the Arduino board does not operate.
    i need your help plz…

  12. michael:

    November 4th, 2012 at 2:43 pm

    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).

  13. ade salau:

    March 5th, 2013 at 11:34 am

    I get a error message saying boolean does not name a type when uploading

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