Step 1: Open up the cases and check the fit.
As you can see by the pics, I laid out everything and decided what to do with the parts I had to work with... I suggest you do the same and see what new ideas you can come up with. I started this project just to find a more interesting way to carry around my usb toys...my Altoids can was good, but I wanted something different. So, I was going to simply take out the battery and make the empty compartment into a storage case.
I decided against soldering my usb devices to extend the connectors. That's when I remembered the 4 port usb hub. You can get these at Target, etc. for under $10.
Step 2: Building the phone
I used a Dremel with a small grinder to remove some of the inside parts of the phone. Do this carefully also and remember to remove the screen and buttons first. You ony want to remove what is absolutely necessary to get the usb hub to fit. Removing too much can weaken the structure of the phone case. Also, be careful NOT to remove important parts (like the lock for the battery cover) I also had to cut out about half of the plastic backing in the battery compartment so that my USB devices would slide in and out easily and a notch for the plug.
Once everything fits, replace the keypad and screen. Use a little hot glue to secure them. Again, just use what's needed. If you go crazy with the glue, you might end up having to remove some of it to get the rest of your parts in place. I secured the USB plug in the bottom of the phone with a little Gorilla Tape and then carefully added hot glue. Make sure the glue will not interfere with plugging in the cord.
In the top right corner of the phone you can see a small magnet. I glued this close to an outside wall and away from the circuits. It will be used later for the alarm. Let the glue dry for a few minutes and then check to make sure your parts a firmly secured. Then snap the back on the phone. Once it is together, you can then plug in your devices. The top device in mine is a 2GB drive and the lower one is a bluetooth adapter. You can change out any combination of these devices to fit your needs, or to upgrade it with more memory. (That's what I like so much about this build). The battery cover should fit easily back in place.
Step 3: Building the Alarm
The pager opens up easily with the removal of a screw and a little careful prying. The alarm came apart with a viscous attack from a pair of pliers (a hammer might have broken something).
I cut off the battery terminals and soldered the wires to the pager terminal. Now it uses 1x aaa battery that the pager used and can be easily replaced. I drilled out a small notch for the on/off switch (the location of the switch determined how I fit the board into the case).
I also relocated the reed switch to the ouside wall of the pager with some telephone wire. It's hard to see in the picture, but it is just above the large shiny disk (the alarm speaker). A reed switch looks like a small glass tube. It is a simple switch that is triggered by a magnet. As a door alarm, you place the alarm on your door and the magnet on the frame. When an intruder opens the door it pulls the magnet away from the reed switch, triggering the alarm circuit.
I replaced the lcd screen and the pager buttons and glued them in place before gluing the alarm parts in place. Be careful with the glue, especially around the edges or it will be difficult to the case back together.
Step 4: Now have fun!!
Place the two together closely until the magnet stops the alarm. Now if someone tries to remove either one, the alarm will sound.
My favorite part about this build is the portability of the devices and their ability to be used for multiple situations. The phone can easily be swapped out with many different types of USB devices (provided you remove their covers to fit). The pager can also be taken with you on trips to secure your hotel room door at night. Just carry a little putty and a magnet with you and the pager alarm can be used for many different things. It does serve the exact same function. I just like the cooler look of the black pager as opposed to the cheesy looking alarm. It looks a little more sophisticated than it actually is as an alarm. So I hope it will be a better looking deterrent.