PullMonkey Blog

Signature Pad in Linux

I'm using the topaz model T L462 HSB. It's nice now that it works. But what a PITA to get it going. The biggest problem with the device is the documentation. There is no low level documentation explaining the representation of the bytes coming in over usb. So you are stuck using their libraries which expose some poorly explained API.

Anyway, like I said, great when it works. So I'm working in linux which basically leaves me having to use java libs and a shared object file.

Here's my code:

It sits and waits until the sig pad gets some points on it. Once we have points it waits for a lapse in time where there is no change in the number of points.
Once we've decided that we have captured a signature, we store it to a file.
Then we shell out to a ruby script - see the httpi and curb article - which is how I get the file to our rails server for display and verification from the user.

Now, you'll need a few files. Most of which can be found in the java zip download from the vendor site.
From that zip, you should grab the following:
SigPlus2_60.jar
RXTXcomm.jar
libSigUsb.so - if you need the 64 bit version, go here - http://www.topazsystems.com/Software/libSigUsb7242012.zip

Then I just used eclipse to set everything up and build. Works well so far.
The only thing you may need to change is the model (I have mine set to SignatureGem1X5) and com port (I have mine set to HID1).

Hello Android – Pindah (with Mirah) Application

Did you install the Android SDK / JDK, etc?  If not, start here - http://developer.android.com/sdk/index.html.
If you're running 64-bit like me, make sure to install the ia32-libs, since the SDK is 32-bit.

This is completely based on the Hello Android tutorial - I didn't really do a whole lot, but the hope is that this will help get some more ruby devs into android development with a simple how-to.

Step 1 - Setup RVM with jruby

Note: RVM is awesome, if you don't use it or don't know about it - read more here.

rvm install jruby
cd /path/to/your/android/pindah/mirah/project/dir/
# using your .rvmrc will trigger `rvm use jruby` when you cd into your project dir.
echo "rvm use jruby" > .rvmrc
# this will make sure your .rvmrc is working, you should then be able 
# to use rvm info and see jruby
cd .

Step 2 - Install the mirah and pindah gems

# too easy
gem install mirah pindah

Step 3 - Create your first pindah app

pindah create com.example.android.hello_world
cd hello_world

Step 4 - Create your activity - HelloAndroid.mirah

# from your project dir and inside your pindah app dir 
<editor> src/com/example/android/hello_world/HelloWorld.mirah

This is the code I used:

Step 5 - Setup your AndroidManifest.xml file

This is where you define your app, version, name, etc, but more importantly for this example - what activity will handle your main intent.
Mine looks like this:

Step 6 - Install to your device

# make sure a device is recognized  ... 
# and make sure adb is in your path (platform-tools in the SDK)
adb devices
rake install

Playing with Mirah

Mirah (formally duby) is pretty freaking cool.   Plans are to scrap java and use mirah for future android development, we'll see.  Here's a rough example of some pretty basic mirah.

To get started, you'll need jruby and the mirah gem:

rvm install jruby
rvm use jruby (or put in your .rvmrc)
gem install mirah

Then create an example:

puts "hello world!!"
500.times do |x|
  puts x
end

Time in ruby:

time ruby test.mirah

...
=> .457s

Compile to Java and time:

mirahc test.mirah
time java Test

....
=> .081s

Less than 1/5 the time and it compiles to Java ... neat 🙂

mirahc -j test.mirah

// Generated from test.mirah
public class Test extends java.lang.Object {
  public static void main(java.lang.String[] argv) {
    int __xform_tmp_1 = 0;
    int __xform_tmp_2 = 0;
    int x = 0;
    java.io.PrintStream temp$1 = java.lang.System.out;
    temp$1.println("hello world");
    __xform_tmp_1 = 0;
    __xform_tmp_2 = 500;
    label2:
    while ((__xform_tmp_1 < __xform_tmp_2)) {
      x = __xform_tmp_1;
      label3:
       {
        java.io.PrintStream temp$4 = java.lang.System.out;
        temp$4.println(x);
      }
      __xform_tmp_1 = (__xform_tmp_1 + 1);
    }
  }
}