Tired of "Hands Free"? - How about "Hands Full" solution?

I used to have an old Motorolla cell phone, actually it wasn't even a phone, back then it was called DPC - "Digital Personal Communicator", which is in my mind sounds much more scientific than a modern "cell phone". So this is used to be an awesome piece of equipment back in its days (actually it was the smallest  phone in 1989), but 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 of disposing 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...

So the first step was to get to the guts of both devices. Cracking open the handsfree was quite simple - it was already broken.

Opening a 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 "phone disassembly will void the warranty" on the label. But I didn't worry about 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 halfs of the phone together (you can see this 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 by a big needle. Additionally, there are two plastic locks that hold shafts in place.

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

  • Remove old PCB, cut off the bottom part of it with the connector and hot-glue it to the case. This connector is used for aestetic purpose only. Originaly I was thinking to ditch the connector, but decided that the big hole on the bottom of the phone won't look very appealing.
  • Hot-glue old display - for aesthetic purpose 
  • Extend hands-free's LED with wires, hot-glue the LED instead one of the old phone's LED (I glued it in place of unlabeled LED in the left bottom corner of the display)
  • Solder phone's mic and speaker to the hands-free PCB
  • Solder phone's volume buttons in parallel to the hands-free volume buttons
  • Trace one of the phone's keyboard button to the white connector, solder in parallelel with hands free ON button
  • Hot-glue hands-free battery (I placed it atop of the LED display), PCB and vibrator motor. Don't forget to isolate 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 the better layout with antenna attached (it's also hot-glued to the case)

Image Cell Open 02

I want the cell phone to look like a normal (super-old) phone, without any additional holes/connector visible from outside. At the same time I need somehow to charge it. The old connector wasn't an option - 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. So 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 :)