Tired of "Hands Free?" - How About a "Hands Full" Solution?

Tired of "Hands Free?" - How About a "Hands Full" Solution?

I used to have an old Motorola cell phone, actually it wasn't even a phone, back then it was called a DPC - "Digital Personal Communicator", which in my mind sounds much more scientific than a modern "cell phone". This is used to be an awesome piece of equipment back in its day (actually it was the smallest  phone in 1989). However, it's quite useless now since it does not support modern networks (it was designed for AMPS network, but this service had been discontinued around 2007).

Image Cell Front

I was thinking about disposing of this device, but luckily I managed to nearly destroy my Bluetooth hands-free (Jabra BT250) by accidentally dropping it and stepping on it. Blending two useless devices together promised an interesting result...

The first step was to get to the guts of both devices. Cracking open the hands-free was quite simple - it was already broken.

Opening the cell phone was a bit more complicated since I wanted to preserve its authentic look. There are four plastic locks underneath the battery and one screw under the label. Ironically, there is a warning on the label: "Phone disassembly will void the warranty." I didn't worry about the warranty.

Image Cell Back

After opening the back cover I realized that something else is holding it - there are two plastic shafts that hold the folding mouthpiece and both halves of the phone together (you can see these shafts on the photo below). You have to pull both shafts towards the center. Fortunately, there is a small hole in each shaft which makes it easy to move using a big needle. Additionally, there are two plastic locks that hold the shafts in place.

Now it's time to lie out and somehow attach the new guts inside the phone:

  1. Remove the old PCB. Cut off the bottom part of it with the connector and hot-glue it to the case. This connector is used for aesthetic purpose only. Originally, I was thinking about ditching the connector, but decided that a big hole on the bottom of the phone wouldn't look very appealing.
  2. Hot-glue the old display for aesthetic purposes.
  3. Extend the hands-free's LED with wires. Hot-glue the LED instead of one of the old phone's LEDs (I glued it in place of an unlabeled LED in the left bottom corner of the display).
  4. Solder the phone's mic and speaker to the hands-free PCB. 
  5. Solder the phone's volume buttons parallel to the hands-free volume buttons.
  6. Trace one of the phone's keyboard buttons to the white connector. Solder it parallel with the hands-free ON button.
  7. Hot-glue the hands-free battery (I placed it atop of the LED display), PCB and vibrator motor. Don't forget to isolate the PCB back (I used pieces of electrical tape). 

    This is my first attempt of the internal layout.

    Image Cell Open 01

    Oops, can't close the case because there is not enough room for the vibrator. Here is a better layout with antenna attached (it's also hot-glued to the case).

    Image Cell Open 02

    I wanted the cell phone to look like a normal (super-old) phone, without any additional holes or connectors visible from outside. At the same time, I needed a way to charge it. The old connector wasn't an option, as I couldn't find the original charger for it. The only option was to add a new connector, and the best location for it was underneath a battery. I drilled a hole and super-glued the connector (I actually reused the connector from the hands-free charging station).

    Image Cell Open with connector

    This is the completed device with connected Jabra charger.

    Image Cell Back with charger

    Have fun hacking the stuff :)


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Resurrecting the Antique Pressure Gauge to Display Internet Bandwidth

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