May

20

John Smiths have a lot to answer for there I can tell you.

It’s been a busy few weeks at work while Selection of widgetswe launch our revamped online shop and how did I go about relaxing? I did more development work at home. Since we’ve moved into our house I haven’t really had a lot of time to do much development, more tiling grouting and renovating than anything else. This last week though, as we started to get on top of things, I took some time to put together a widget for Android. I’ve been collecting, storing and graphing data from various sensors around the house for some time now and while the graphs are pretty they aren’t really a quick or efficient way of reading the status at a glance.

Step forward the widget. Each widget requests XML data from the server and presents it on the widget, this allows an infinite number of widget variations since the only change is the data received. In other words, if it’s in the database it can be served. The widget itself has a number of coloured backgrounds which the server data can trigger if and it’s also capable of playing an alarm sound if required. I still need to fix this because the alarm sound triggers on each update and there’s currently no way to tell the widget to be quiet.

Update: Fixed this, tapping the widget will silence it until the next alarm trigger ie once the state returns to normal and then alarms once again.

Incidentally, since I only have a self signed certificate on my server but still wanted encrypted access I had to extend the DefaultHttpClient. By default Android will just refuse to connect to a server if the certificate isn’t signed by one of the ‘trusted’ certificate authorities – it wont tell you that it refused, it’ll just silently fail. You’d only ever really know if you’d connected to your device via adb and done a logcat. You can get round this by adding a keystore to your application, which is good enough for testing or personal applications.

If you want to do this you need to make sure you have the Bouncy Castle cryptography jar in your CLASSPATH. The first thing you’ll need is a copy of the certificate which I hope you’ve generated and installed on your server. If you need to get a remote server certificate you can use the following command (all one line).

echo | openssl s_client -connect your.server.goes.here:443 2>&1 |  
sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > mycert.pem

Replace the “your.server.goes.here” with your server, obviously. Once you’ve done that export the CLASSPATH to the Bouncy Castle jar you downloaded replacing the path I’ve used with the location you downloaded it to:

export CLASSPATH=bcprov-jdk16-146.jar

You can now use the following script, note that the keystore name is appkeystore.bks as on line 3

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#!/bin/bash
 
CERTSTORE=appkeystore.bks
 
if [ -a $CERTSTORE ]; then
    rm $CERTSTORE || exit 1
fi
 
keytool \
      -import \
      -v \
      -trustcacerts \
      -alias 0 \
      -file <(openssl x509 -in mycert.pem) \
      -keystore $CERTSTORE \
      -storetype BKS \
      -provider org.bouncycastle.jce.provider.BouncyCastleProvider \
      -providerpath /usr/share/java/bcprov.jar \
      -storepass MyPaSsWoRd

Replacing the MyPaSsWoRd on line 19 with a password of your choosing, you’ll need it later too. If you run the script you should get some output like this, obviously with your server information – remember to answer yes to the “Trust this certificate” prompt.

 
Owner: EMAILADDRESS=info@ automated.it, CN=www.automated.it, OU=Tech, O=Automated IT, L=Eye, ST=Suffolk, C=GB
Issuer: EMAILADDRESS=info@ automated.it, CN=www.automated.it, OU=Tech, O=Automated IT, L=Eye, ST=Suffolk, C=GB
Serial number: 4dce9c74
Valid from: Sat May 14 16:15:00 BST 2011 until: Sun May 13 16:15:00 BST 2012
Certificate fingerprints:
	 MD5:  32:0F:33:0C:42:8D:FF:78:90:46:31:7A:4F:D3:33:23
	 SHA1: BD:A8:B8:21:B1:48:C3:53:BB:01:22:65:9E:00:6E:14:7B:DE:4E:F6
	 Signature algorithm name: SHA1withRSA
	 Version: 1
Trust this certificate? [no]:yes
Certificate was added to keystore
[Storing appkeystore.bks]

Create a directory called “raw” in your project’s ‘res‘ folder and copy the appkeystore.bks file to it.

In your Android application or widget you can now create a new class for the following code which will extend the original DefaultHttpClient class. You’ll want to change the package name on line 1 to match your application.

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package your.package.name.here
 
import android.content.Context;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.SingleClientConnManager;
 
import java.io.InputStream;
import java.security.KeyStore;
 
public class myHttpClient extends DefaultHttpClient {
 
  final Context context;
  public String UserAgent="Android dataWidget (ScaredyCat 0014150511-0.1b) [http://blog.automated.it]";
 
  public myHttpClient(Context context) {
    this.context = context;
  }
 
  @Override protected ClientConnectionManager createClientConnectionManager() {
    SchemeRegistry registry = new SchemeRegistry();
    registry.register(
        new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
    registry.register(new Scheme("https", newSslSocketFactory(), 443));
    return new SingleClientConnManager(getParams(), registry);
  }
 
  private SSLSocketFactory newSslSocketFactory() {
    try {
      KeyStore trusted = KeyStore.getInstance("BKS");
      InputStream in = context.getResources().openRawResource(R.raw.appkeystore);
      try {
        trusted.load(in, "MyPaSsWoRd".toCharArray());
      } finally {
        in.close();
      }
      return new SSLSocketFactory(trusted);
    } catch (Exception e) {
      throw new AssertionError(e);
    }
  }
}

Note that the password used in the script earlier should match the one on line 37- use your own different password in production for security purposes. You can now use the class as required in your application, for example:

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myHttpClient httpclient = new myHttpClient(context);
 
httpclient.getCredentialsProvider().setCredentials(new AuthScope(host, port), new UsernamePasswordCredentials(username,password));
BasicHttpContext localcontext = new BasicHttpContext();
BasicScheme basicAuth = new BasicScheme();
localcontext.setAttribute("preemptive-auth", basicAuth);
 
httpclient.addRequestInterceptor(preemptiveAuth, 0);
 
HttpHost targetHost = new HttpHost(host, port, scheme); 
 
HttpGet httpget = new HttpGet(url);
httpget.setHeader("User-Agent", httpclient.UserAgent );

Once I’d got the SSL connection I could get the application to download a list of sensors from the database, this only happens the first time the first widget is added to the home screen. I need to sort a way of allowing the user to delete the list if more sensors are added. At the moment clearing the data for the widget application works but it erases the widget settings too.

When I’m at home I want to connect to a local server for the information for the widgets and when I’m out and about (using a 3G connection) I want to connect to an external server. I implemented the ability to automatically switch when my phone connected to my WiFi access point. One final thing I did was to add the ability to long press on a text field and then select ‘Save as default‘ allowing things like servers, Wifi MAC address, username and password to be saved as the defaults for all widgets.

First run, download sensorsSelection of widgetsWidget settingsSave as default

 



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May 20, 2011 21:10

Jan

18

LinkUSB(i) and 1-Wire setup

3 years ago, mid-January | 2 Comments

I’ve just configured my monitoring machine to use a LinkUSBi 1-Wire interface and it’s a rather simple process. First of all we’ll setup One Wire File System, or OWFS LinkUSB(i)for short, then we’ll add some udev rules and finally plug in a device and get some readings. Since we need to build OWFS we’re going to need a new libraries and files installed, I’m making the assumption that you already have automake, autoconf, autotools-dev, gcc, g++ installed so you can go ahead and install the libraries we need.

apt-get install libtool libusb-dev fuse-utils libfuse-dev swig python2.6-dev tcl8.4-dev php5-dev

You don’t actually have to have Python, Tcl or php5 installed if you don’t want them they add to the interfaces you can use with OWFS – unless you specifically don’t want them you may as well include them. Once the installs above have completed you’ll need to get a copy of OWFS – be sure to download the latest version of it.

Update : I’ve rolled back to using 2.8p4 since 2.8p5 seems to have some problems with owserver (owfs still works fine).

Once you’ve downloaded you’ll see the file is called something like owfs-2.8p5.tar.gz – this file name is made up of owfs-[version of owfs].tar.gz In my case I have version 2.8p5. Your version may differ, don’t worry about that (unless it’s older!). Now extract the tarball with

tar -zxvf owfs-2.8p5.tar.gz

replacing the file name with whichever version you downloaded. This will extract a lot of files and place them in a directory with the same name as the file you downloaded, minus the ‘.tar.gz’. Move to that directory with

cd owfs-2.8p5

now we need to run the configure and make scripts. First configure, if this fails make sure you have all the dependencies required.

./configure

this will spit out reams of text which really only matters if something goes wrong. The last few lines should be something like this

Current configuration:

Deployment location: /opt/owfs

Compile-time options:
Caching is enabled
USB is enabled
I2C is enabled
HA7Net is enabled
W1 is enabled
Multithreading is enabled
Parallel port DS1410E is enabled
TAI8570 barometer is enabled
Thermocouple is enabled
Zeroconf/Bonjour is enabled
Debug-output is enabled
Profiling is DISABLED
Tracing memory allocation is DISABLED
1wire bus traffic reports is DISABLED

Module configuration:
owlib is enabled
owshell is enabled
owfs is enabled
owhttpd is enabled
owftpd is enabled
owserver is enabled
ownet is enabled
ownetlib is enabled
owtap is enabled
owmon is enabled
owcapi is enabled
swig is enabled
owperl is enabled
owphp is enabled
owpython is DISABLED
owtcl is enabled

Now we build OWFS using make

make

After some churning, spewing output, cpu usage and warning messages (ignore them), which may all take 10 minutes or more depending on your cpu and memory, you should get your prompt back. Finally install owfs – do this as root.

make install

Since we need to mount the OWFS somewhere we create a directory

mkdir /var/lib/1wire

Ok, so now we come to the hardware side of things – I got my LinkUSBi from HomeChip – the ‘i’ variant has it’s own identity which may or may not be useful to you. If I’m honest I accidentally picked the ‘i’ version and could have easily saved 80 pence and gone for the non-‘i’ version without trouble – Quick Note, as I write this Quinten has had some issues that need investigation, he has the non-‘i’ variant – for now I’d stick with the ‘i’ variant that we know works. I’ll update once I get more information about the issue. Turns out that version 2.8p4 of OWFS worked with the LinkUSB for Quinten. The LinkUSB or LinkUSBi is the interface to 1-Wire devices, so now’s the time to plug it in. Be aware that if you have other FTDI devices you might want to set up some udev rules. This is what I have in a file called /etc/udev/rules.d/60-usb-serial.rules


# /etc/udev/rules.d/60-usb-serial.rules
# Determine XBEE, Current Cost and 1wire USB ports

KERNEL=="ttyUSB*", \
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{serial}=="A600eD0C", \
SYMLINK+="1wire"

KERNEL=="ttyUSB*", \
ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", \
SYMLINK+="currentcost"

KERNEL=="ttyUSB*", \
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", \
SYMLINK+="xbee"

Since I have 3 USB serial devices, a currentcost unit, some Xbee based wireless 1-wire devices I made and the LinkUSBi, two of which are FTDI I need to identify each so use the ATTRS{serial} to uniquely identify the LinkUSBi via its serial number. You can glean the serial number by using

lsusb -vv

and look at the output for the serial number of device you’re interested it. Once our LinkUSBi is connected and detected we can mount OWFS with

/opt/owfs/bin/owfs -d /dev/1wire -m /var/lib/1wire

Note that I use -d/dev/1wire because my udev rules create a symlink. If you don’t create the symlink then your device will be something like /dev/ttyUSBx – where x = a number. Now we can look at any attached devices with

# ls /var/lib/1wire/
01.BA0E0E140000 28.1842A1020000 alarm bus.0 settings simultaneous statistics structure system uncached

The 01.XXXXXX device is the LinkUSBi and the 20.XXXXX device is a DS18S20 temperature sensor. To read the output of the temperature sensor we simply do

cat /var/lib/1wire/28.1842A1020000/temperature
16.0625

As you can see the temperature is a rather chilly 16.0625 degrees Celsius. Stuart Poulton has some 1-Wire kits available to buy for creating some domestic environment friendly temperature sensors and Quinten has some good pictures of them. Kevin has also got some newer pictures up – thanks for the headsup Kevin.



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January 18, 2011 20:47

Apr

25

G1 Assault on battery

5 years ago, at the end of April | Leave a Comment

I know I’m late to the party but a few days ago I received a small package containing a T-Mobile G1 phone running Android. The first thing I did was go to unlock-now to get myself a SIM unlock code. After submitting my details and paying up the 17.50 EUR it was just a case of waiting for the email, about 3 hours in my case. The email details G1everything you need to know when unlocking, particularly useful is the info on setting up a new APN which you’ll need to do if you aren’t using T-Mobile as your carrier. My O2 PAYG SIM from my iPhone worked fine and soon the G1 was syncing happily with gmail. One of the things that struck me about the G1 was all the negative comment on it’s size and feel that I’d read in various blogs and reviews. Personally I couldn’t see and issue with either the thickness of the device or the the look and feel of it and I wasn’t alone in that. I really don’t see what all the ‘complaints’ were about.

One of the things I had heard though, that I can confirm, is the poor battery life. Without installing any extra software the only real control over the G1’s power management seems limited to turning off the GPS or WiFi. However, there is a ray of light. After installing Power Manager things improved immensely but it still wasn’t enough. The solution I settled on was to buy an extended, 2400mAh, battery which came with a replacement back. The battery is physically 2 or 3 times the thickness of the original, which is why you get a replacement and the end result is a device that’s about as thick as a NOKIA N95.

So why didn’t I wait for a G2? Simple really. The G1 has a wonderful physical keyboard. I really can’t stand on screen keyboards, perhaps I’m a minority.

Of course the other reason that I wont be getting a G2 is that Vodafone are capping both daily and monthly usage when you sign up – 15mb / day and 500mb a month. Perhaps everyone at Vodafone still uses a 6310? Maybe they just don’t like the G2 or Android. Who knows?

Update (Sunday 10th May) : G1 Running cupcake has been running for 3 days with the extended battery and no charging!



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April 25, 2009 22:27

Mar

21

Originally I wasn’t going to blog about this but I finally gave in so here it is. This isTracking weather another one of those things that you really just can’t do with your iPhone unless you’ve jailbroken it.

Having the weather on your lock screen is nothing particularly new, there are enough Winterboard themes that allow you to do this. However, this is slightly different. I’ve never really understood why you’d only ever want to know what the weather was like in your home town. What does it matter? That is of course unless you never actually go anywhere. Why not have the weather for where you are? Yes I know you could just look out of the window or actually go outside but that’s beside the point. What I wanted was to have the weather for where I actually am right now. So, as part of my iPhone tracking system I added the ability for the weather to follow me too. The implementation is rather simple.

Since I’m already sending my location and retrieving the wallpaper image I’m also getting an override (overRide.js) for my weather configureMe.js. The overRide.js contains a single line, the location – as per the configureMe.js format:

var locale="Lelystad,NL"

So each time the wallpaper is updated, so is this file. One of the key things you need to do to accomplish this for yourself is what is called reverse geocoding. That is, getting the name of your location from your GPS coordinates.

Now, the best way I’ve found of doing this so far is by using geonames this is a fantastic site that allows you to do the reverse geocoding without even blinking. For example, calling geonames using the url

http://ws.geonames.org/findNearbyPlaceName?lat=50.455&lng=-3

would result in the following xml being returned

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
  <geonames>
    <geoname>
        <name>Seaton</name>
        <lat>50.7049382166946</lat>
        <lng>-3.06999206542969</lng>
        <geonameId>2638278</geonameId>
        <countryCode>GB</countryCode>
        <countryName>United Kingdom</countryName>
        <fcl>P</fcl>
        <fcode>PPL</fcode>
        <distance>28.2265</distance>
    </geoname>
  </geonames>
</xml>

This gives you pretty much everything you could possibly want and for free too. Note the inclusion of your distance between your coordinates and the the coordinates returned (nearest named location).

Now I know what you’re thinking. Why would I retrieve a file with the data in it from my server, why not parse the xml in the javascript on the lock screen. You’re right, I could and you, possibly, should. I don’t because I keep all my GPS data in a database on that server so I update the database with the actual locations too. I don’t parse the xml on the iPhone because I don’t need to.

Of course I haven’t yet tested being in some obscure location that the weather provider doesn’t know about. Incidentally, geonames is so freaking good that, if you want to, you can download a daily dump of the database.

Lock screen weatherLock screen weather, later that day



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March 21, 2009 18:11

Mar

5

Pachube dials without the heartache

5 years ago, at the start of March | 1 Comment

Some people might not want to have their own web server and php installs just to use their Pachube feed to show a dial or two so let me introduce to you the simple way of getting this all to work. Go over to my Pachube app page and follow the on screen instructions. You’ll end up with some text to copy and paste into your web page. All done for you all lovely and simple.

Update Added the ability to de-wiggle the value needle, and then fixed a bug in the wiggle.



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March 5, 2009 16:51

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