Sunday, December 30, 2012

PAW - Using other Languages with CGI

This post is about using other languages apart from BeanShell and PHP. PAW includes a CGI Handler to execute scripts by using the Common Gateway Protocol (CGI). This handler is also used by the PHP plugin to call the CGI version of PHP. The handler is defined inside the file PAW_HOME/conf/handler.XML. Instead of using PHP we will use Perl to create a simple web page.

Finding the Executable Path

First thing to do is to install the SL4A and Perl APK from the Android Scripting Project: After installing the APKs and extracting Perl it's time to find out where the Perl executable is located. One way to do it is to execute the Perl interpreter and to use a terminal emulator and run the ps command. In the case of Perl the executable is located here: /data/data/com.googlecode.perlforandroid/files/perl/perl

CGI Configuration

Now it's time to edit the PAW handler configuration. Open the file PAW_HOME/conf/handler.XML and add the following lines below the Basic Auth Handler configuration:
 <handler status="active">
    <name>Perl CGI  Handler</name>
    <description>Perl CGI  Handler</description>
    <files />
      <param name="perlCgiHandler.class" value="org.paw.handler.AndroidCgiHandler" />
      <param name="perlCgiHandler.root" value="[PAW_HOME]/html" />
      <param name="perlCgiHandler.suffix" value=".pl" />
      <param name="perlCgiHandler.runwith" value="/data/data/com.googlecode.perlforandroid/files/perl/perl" />
      <param name="perlCgiHandler.sl4a" value="true" />
      <param name="perlCgiHandler.ENV_TMPDIR" value="[PAW_HOME]/tmp" />
Let's have a look at the parameters. The class parameter defines the handler to use. In our case this is the CGI Handler. The next parameter is the root parameter which specifies the directory the scripts are located. Subdirectories are also included. The suffix parameter defines the filename extension for the scripts. The runwith parameter is the most important one, it defines the location of the CGI binary. If the sl4a is set to true the environment variables AP_HOST and AP_PORT are set. Because this information is read from logcat entries, SL4A should be started right before the startup of PAW. Otherwise it might not possible for the handler to extract the SL4A configuration. The last parameter sets the TMPDIR environment variable. All parameters starting with ENV_ are used to set environment variables. Now the PAW configuration is complete and we can start to write a test CGI script.

The CGI Script

We will create a test CGI script inside the PAW_HOME/html directory called The test script looks like this:
print "Content-type: text/html\n\n";

print "Hello world!\n";
After starting PAW and entering the URL http://<ip-address>:8080/ into the address bar of the browser the following text should be displayed:
Hello world!


The Android Scripting Project offers many more interpreters. It should be possible use many of them together with PAW, as long as you can get them to work from the command line.

Monday, August 6, 2012

Cache Beacon (beta) - Introduction

This is a post about the Android app Cache Beacon that supports Wireless Cache Beacons on Android.
Garmin® introduced Wireless Beacons in the form of their Chirp™ device almost two years ago.

Cache Beacon is no longer available at Google Play.
The reason is that there is now an official ANT+ Plugin Sampler that includes the functionality of Cache Beacon.
It also allows to write Chirps which was not possible with Cache Beacon and is more stable.
Cache Beacon was ok as long as there was no other implementation of the protocol.

The ANT+ Plugin Sampler can be found here:

A Wireless Beacon can contain cache information like cache name, coordinates and hints.
These information is transmitted via the ANT+ protocol. Some of the Garmin GPS devices support these beacons.
Accessing the information from other devices is complicated, because most devices lack an integrated ANT+ chip.

There are solutions for iPhones and iPads by purchasing a separate BlueTooth ANT+ adapter.
Unfortunately these adapters are quite expensive.

Although the ANT+ Geocaching Device Profile is open there didn't exist a solution for Android devices to access Wireless Beacon until now.
Cache Beacon is an Android app that makes it possible to read the beacon information.

Note: The app is still in beta, so there might be bugs.

To use this app a Sonx Xperia device or an Android device with USB host support is needed.

The maximal distance varies from device to device. When testing, the max. distance with the Xperia device was approx. 2 meters. With an USB adapter it was possible to stay up to 4 meters away.

Sony Xperia Devices

There are some Sony Xperia devices that have an integrated ANT+ chip.
The app should work with these devices without any modification.

Sony Xperia pro

Here is the list of supported Sony devices:
Sony Xperia arco S
Sony Xperia S 
Sony Xperia ion 
Sony Live with Walkman 
Sony active
Sony Xperia arc 
Sony Xperia arc S 
Sony Xperia mini
Sony Xperia mini pro
Sony Xperia neo
Sony neo V 
Sony Xperia pro
Sony Xperia ray
Sony Xperia X8
Sony Xperia X10 mini
Sony Xperia X10 Mini pro

The app has been tested with a Sony Sony Xperia pro (Android 2.1).

USB Host Mode

In addition Android since version 3.1 supports USB Host mode together with an USB OTG adapter.
If USB host mode is supported by the Andrdoid device an USB2 compatble ANT+ USB adapter can be used to add ANT+ support.

USB OTG Apter and SUUNTO Movestick Mini

This has been tested with the following configuration:
Galaxy Nexus, SUUNTO Movestick Mini

After starting the app, the app will tell you if USB host is supported or not.

Result Intent

The app can be also called from another app by using a Result Intent.
The Intent Action to use is:

The resulting Intent contains some Intent Extras.
Here is the list:

BEACON_NAMEStringCache NameGC123456
BEACON_HINTStringHintfollow the white rabbit
BEACON_VISITSIntegerVisit Count4
BEACON_LAST_VISIT_DATELongMs since 1.1.19701344249202000
BEACON_BATTERYStringBattery StatusOk


Google Drive: Cache Beacon

Monday, June 25, 2012

Tinkering with PAW

This blog post is about using Tinkerforge modules together with PAW Server for Android.
As an example a volume control for Android is build.

The Setup
The following image shows the components needed to build the volume control.

Component Overview

The LCD and Poti Bricklets are connected to the Master Brick which is connected via USB to a PC running the brickd (Brick Daemon).
The Poti is used to control the volume of the phone. The values will be displayed on the LCD.

Below is an image of the  setup in action.

Complete Setup

Tinkeforge Classes
Tinkerforge offers a set of language bindings which also includes a Java JAR package.
Because PAW needs DEXed classes the Tinkerforge JAR file has to be converted into DEX format.

To make live easy, here is the link: Tinkerforge_dex.jar

To make the file usable for PAW, copy it int the /sdcard/paw/webconf/dex folder and restart the server.

Inside the Beanshell Console of the PAW web interface you can run the following code to check if the file has been loaded.


For me, the output looks like this:

If the output includes the Tinkerforge_dex.jar file, everything should be ok.

Bricklet UIDs
In order to talk to the right Bricklets (LCD and Poti) the UID of these components is needed.
Inside the scripts provided in this post, you have to exchange the connection IP address and Bricklet UIDs accroding to your setup.

To find out the UIDs we can ask the Master Brick obout its configuration.


import com.tinkerforge.IPConnection;

// Change IP address!
host = "";
port = 4223;

ipcon = new IPConnection(host, port); // Can throw IOException

ipcon.enumerate(new IPConnection.EnumerateListener() {
    public void enumerate(String uid, String name, short stackID, boolean isNew) {
        if(isNew) {
            $$.print("Name: " + name);
            $$.print(" | UID: " + uid);
            print(" | Stack ID:" + stackID);


With my setup the output looks like this:
Name: Master Brick 1.0 | UID: apaYNJF7xmN | Stack ID:1
Name: Rotary Poti Bricklet 1.0 | UID: 9BY | Stack ID:2
Name: LCD 20x4 Bricklet 1.0 | UID: 9dj | Stack ID:3

Volume Control Script
One note  about the script...
The script uses polling which is not ideal, actually listeners should be used.
Polling is used for the sake of simplicity.

After we have connected the components and found out the UIDs we can run the volume control script.
Remember to change the IP number and the UIDs.


import android.content.Context;

import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletRotaryPoti;
import com.tinkerforge.BrickletLCD20x4;

r = new Runnable() { public void run() {

    MAX_LABEL = "Max Volume: ";
    DEGREE_LABEL = "Degree: ";
    VOLUME_LABEL = "Volume: ";

    service = server.props.get("serviceContext");
    audioMgr = service.getSystemService(Context.AUDIO_SERVICE);
    maxVol = audioMgr.getStreamMaxVolume(AudioManager.STREAM_MUSIC);

      UID and IP settings ... these have to be changed!
    host = "";
    port = 4223;
    UID_LCD = "9dj";
    UID_ROP = "9BY";

    ipcon = null;

    lastVol = -1;
    lcdFirst = true;

    while(true) {
        try {
            // Make sure we have a valid connection
            if(ipcon == null) {
                ipcon = new IPConnection(host, port);
                rop = new BrickletRotaryPoti(UID_ROP);

                lcd = new BrickletLCD20x4(UID_LCD);

            if(lcd.isButtonPressed((short) 0)) {

            deg = rop.getPosition();
            pos = deg + 150;
            vol = pos * maxVol / 300;
            if(lastDeg != deg) {
                if(lcdFirst) {
                    lcd.writeLine((short) 0, (short)0, MAX_LABEL + maxVol);
                    lcd.writeLine((short) 1, (short)0, DEGREE_LABEL + deg);
                    lcd.writeLine((short) 2, (short)0, VOLUME_LABEL + vol);
                    lcdFirst = false;
                else {
                    lcd.writeLine((short) 0, (short) MAX_LABEL.length(), "" + maxVol + "  ");
                    lcd.writeLine((short) 1, (short) DEGREE_LABEL.length(), "" + deg + "  ");
                    lcd.writeLine((short) 2, (short) VOLUME_LABEL.length(), "" + vol + "  ");

            if(lastVol != vol) {
                audioMgr.setStreamVolume(AudioManager.STREAM_MUSIC, vol, 0);

            lastDeg = deg;
            lastVol = vol;
        catch(e) { }

        // Wait 100 millis until we poll again

    lcd.writeLine((short) 0, (short) 0, "Bye bye ...");


t = new Thread(r);

Some notes about the script:
  • If button 0 of the LCD is pressed, the script will terminate.
  • The Android AudioManager is used to control the music stream volume.
The below picture shows how the display looks like on the LCD.

LCD Output

Android restarts the PAW service from time to time (for whatever reason). So if the scripts stops working just restart it again.
You can also put the script (name is something  like S_tf_volume.bsh) inside the /sdcard/paw/etc/init/1 folder to make sure it's run each time the servers starts up.

Hope this was interesting ... have fun :)

Tuesday, March 20, 2012

PAW Runtime & PHP

PAW Runtime has been updated to support PHP.
To install PHP for the runtime version of PAW, download the file (link below) and unzip it to /sdcard of your Android device.

After starting PAW Runtime a PHP menu entry should be available.
After selecting the entry the page shown below should appear...

PHP Setup
Make your selections and press the Install button. PHP should be available after a restart of PAW Runtime.

If you wold like to get rid of unnecessary files and the menu entry, you can delete the file /sdcard/paw-runtime/webconf/apps/php_setup.conf and everything inside the  /sdcard/paw-runtime/html/php_setup directory except the conf directory.

PAW Runtime
PHP Setup

If you have problems to download above files from the original source, try to use the alternative RapidShare links below:

Thursday, February 16, 2012

DavDrive and USB

DavDrive can be used via USB connection. This might come in handy if no WiFi connection is available.

For this to work ADB the Android Debug Bridge has to be installed on the PC.
This is the most complicated part of the setup.

I will not describe how to setup ADB. You will find instructions by asking Google or by watching below Youtube video.

After ADB is set up, the ADB command adb devices should show your device.
In my case (with my Galaxy Nexus) it looks like this:

List of devices attached
01498B1F0C003012    device

Now start DavDrive and execute the following ADB command on your PC:

adb forward tcp:8888 tcp:8888

This will forward the port 8888 of your PC to port 8888 on your Android device.
If you have another port configured use that one.

Now you can use the following URL to access DavDrive on your Android device:


That's it :)

Note: Everything mentioned above is also valid for PAW.

Thursday, January 26, 2012

Changing the PirateBox Location

This post gives a quick overview what has to be done to move the PirateBox installation to a different directory.

By default the PirateBox HTML files are located in the directory /sdcard/paw/html/app/plugins/piratebox_plugin/html and uploaded files are stored in the folder uploads inside the HTML directory.

I'll demonstrate what to do to move the PirateBox to a different directory (in my example /sdcard/piratebox_ext). You can of course also use a directory on an external SD card.

Copying the HTML Directory
First thing to do ist to create the new folder /sdcard/pireatebox_ext.
Now copy the directory /sdcard/paw/html/app/plugins/piratebox_plugin/html to the new location /sdcard/pireatebox_ext.

As a next step we will edit the PAW server configuration.

Changing the PAW Configuration

The configuration file used for PirateBox is named handlers.xml and it's located inside the /sdcard/paw/html/app/plugins/piratebox_plugin/conf directory.
Edit this file and replace each occurence of /sdcard/paw/html/app/plugins/piratebox_plugin with /sdcard/piraebox_ext.

Changing the Web Pages
Last step to do is to edit the files list.xhtml and pb.xhtml inside the /sdcard/piratebox_ext/html directory.
In each file there is one line that defines the upload directory.
Again, change each occurence of /sdcard/paw/html/app/plugins/piratebox_plugin to /sdcard/piraebox_ext.

That's it ... on next startup the new PirateBox location should be used.