Intro: Samsung MOD (fixed ... Mobile ... TV)
Ever dreamed of making your mobile TV fixed? Would'nt it be nice to watch the mobile channels from your pc?
This is how it could be done.
But your Samsung SGH-P900 will not work mobile anymore ... be warned ! ;-)
Step 1: Disassemble the Device
It's easy to disassemble the Samsung. There are some screws on the back of the device. You only need a small phillips screw driver. Peel of the small rubber pads on the top of the mobile phone. There are small screws underneeth. There are 6 screws on the back that holds the case together.
As soon as the screws are removed the device could be opened. There are some plastic noses that could be opened easiely.
I like to connect to the keyboard to be able to control the device remotely. But the connector or the keyboard has got very tiny connectors. No chance to solder here without destoying the device.
I thought it would be best to solder directly on the button pads. Doing that the keyboard will get unusable and the device could never be put into it's initial state.
This is the point of no return!
Step 2: Hairy Device ...
Nothing more to say here but ... is'nt it beautiful ?
All wires soldered, ready for connection.
Step 3: The Interface
For the first version of the interface i wanted to use only parts that I already had in my lab. I decided to build an interface that should be connected to the parallel printer port of my pc. There are 24 keys on the phone that I liked to simulate. I decided not to connect to the loudness control switch.
To connect to each button I needed a latched port expander using 74LS259 and 74LS138 TTL ic's. To press the buttons I used some old CD4066 analog switches.
See the attached logic plan. I soldered the parts on an evaluation board with small wires. On the borad I put also a voltage regualtor LM78L05 and some capacitors. The power regulator is a standard application to get a regulated power for the ic's. I connected a old, unregulated AC-DC charger.
You can see the setup on the attached pictures.
Step 4: Remote Controlling
As you see on the picture the device still works ;-)
To control all this I needed to write a small program. It had been many years since I did i/o programming on MS-Windows pc's. I found out that i/o programming has changed on 32bit systems like Windows-XP.
It took some time to find an universal IO-Driver-Kit on the internet. Using this kit it is possible to do i/o programming using port commands in c.
The result is a small command line program that can "press" keys on the phone.
If you like, I can add the source code of the program and record a video of the usage ;-)