At xmas I got my father's old NTM Talkman phone. I looking people who are ready to help me and same time convert his/her own old phone to working in gsm network.
I had long time idea to convert fixed phone to gsm phone. So I bought Arduino GPRS shield. I study it and find it easy to use with AT-commands. Then I studied arduino keypad library (matrix keyboard) and made my fixed line phone keyboard to working. After this I hit to problem. Mainly personal and because eight years in Nokia service is all what is needed to get pension (in my case), I have problem to concentrate to things where I need to connect things together in my mind.
I still want to make Talkman working with GSM network. Now I ask help from you. I'm making open source project to convert old fixed or mobile phone to gsm phone.
There is few things what need to clarify before we continue. 1) Power - Lithium - old fashion 12v battery - 5v power supply
All these need to keep in mind. I belive that at beginning of project we use only 5v power supply. Later I need to choose between 12v accu or lithium batteries.
2) two arduino system or one?
- One arduino manage keyboard, leds and LCD screen and other manage gsm-services and power.
- One arduino (Mega?) manage everyhing
When I tested fixed phone conversion, I found that Uno have just needed count of IO ports for handle a keyboard, phone and leds. I used ws2811 leds, so only one port was needed to handle 3 leds. TalkMan have mush more features what need to make working, so UNO have too few IO ports.
Also I want to make this so that anyone who want convert any other phone can more easier to use it his/her own project. So user interface should be taken to own arduino.
If project build system by using Mega alone, it might be possible. Handle have 25 pin connector, so I need only clarify how many are wired. There isn't place for Mega in handle, so in this case All electronics should put in main part of Talkman.
Needed GSM-services in priority:
- GSM network status & PIN management
- Phone call/answer
- Name list management (on SIM) and lowest
- SMS reading/writing or autoanswer/forwarding to other gsm number
- 4x4 keyboard
- on/off power switch and small s-button, top side
- + - buttons left side
- CS, M, R buttons, right side
Lights (leds) under keyboard
- HF - hands free
and without text
- 2x orange leds in middle
- LCD and keyboard backlights
- From handle to phone : 25 pin D-port
- Antenna port (SMB, need to change)
- 6 pin port for power, external antenna, hands free etc (need to change)
I will open Talkman soon, and if you have hw or software related questions, shoot them. I will collect answers and write them here. Also if anyone have answers for these questions, you are free to help me/us.
At least I need to find what LCD controller is used and can it be use by arduino or in worst case I need to measure LCD size and find new LCD or LED screen instead.
Second question is that what kind keyboard matrix is on handle.
Last what I will check is handle connectors wiring. Are all wires usable in project.
With GPRS shield I have one Mega, two arduino mini pros, leonardo and 12v to 5V DC converter. Also I have LiOn charger board and DC booster to 5v.
PS. Yes this mail might be confusing, but so I am ;)