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Retro-Comm
Introduction
- My goal with this project is to make an old rotary phone work again
- The phone should connect to a modern telephone netowrk and be used reliably as a communication device
- It will have all of its old features working:
- rotary disc for selecting the phone number to be called
- ringing bells for incoming calls
- receiver being lifted to answer a call / initiate a call
- As well as some new features to give it a modern twist:
- ability to save important numbers in memory for faster calls
- custom ringtones
- The main reason why I chose this project was that it offered me the posibility to reverse engineer an interesting old system while also applying the principles learnt during the semester at PM
- The ideea came from the similar project implemeted last year at the PM Fair, which I really liked and I hope I can improve, but also from a few other online sources mentioned in the bibliography section
General Description
The phone works as follows:
- Whenever the receiver is placed in the stand the phone is in settings mode, when the user can change the ringtone, add new phone numbers into memory or call saved numbers, all using the disc for selection
- When the receiver is taken away from the stand the user can select a number to be called using the disc. The arduino will read the disc signals, will construct the number in a string and the pass it via USART to the SIM800L module using the AT command for calling (ATD+number). If the reciever is placed in the stand during the call, the arduino will send the hang up command (ATH)
- When a call is incoming, the RING line from the SIM800L will be set LOW, indicating to the arduino that someone is calling. The arduino will then ring the bells using an electromagnet powered by the MOSFET module, acording to the current ringtone
- Mic and speaker are handled by the SIM800L
- Supply voltage (12V) will be lowered using MP1584EN modules to 4V for the SIM800L and 5V for the arduino
Hardware Design
- Components
| Component | Role | Quantity |
|---|---|---|
| Arduino Pro Micro | Controlls all other components | 1 |
| SIM800L | 2G communication | 1 |
| MOSFET module | Allow the 12V supply to connect to electromagnet | 1 |
| Electromagent | Pull the hammer rod that will hit the bells | 1 |
| MP1584EN module | Step down the 12V voltage for SIM800L and Arduino | 2 |
| 10 kOhms resistor | Voltage divider for the SIM800L | 3 |
| 1000 uF capacitor | Regulate current for SIM800L during 2A busrsts | 1 |
| Electret microphone | Record the voice of the user | 1 |
| 1N4007 diode | Stop the reverse voltage from the elctromagnet | 1 |
| Perfboard | Base used to solder the components | 2 |
- scheme electrice (se pot lua şi de pe Internet şi din datasheet-uri, e.g. http://www.captain.at/electronic-atmega16-mmc-schematic.png)
- diagrame de semnal
- rezultatele simulării
Software Design
Descrierea codului aplicaţiei (firmware):
- mediu de dezvoltare (if any) (e.g. AVR Studio, CodeVisionAVR)
- librării şi surse 3rd-party (e.g. Procyon AVRlib)
- algoritmi şi structuri pe care plănuiţi să le implementaţi
- (etapa 3) surse şi funcţii implementate
Rezultate Obţinute
Care au fost rezultatele obţinute în urma realizării proiectului vostru.
Concluzii
Download
O arhivă (sau mai multe dacă este cazul) cu fişierele obţinute în urma realizării proiectului: surse, scheme, etc. Un fişier README, un ChangeLog, un script de compilare şi copiere automată pe uC crează întotdeauna o impresie bună 
.
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Fişierele se încarcă pe wiki folosind facilitatea Add Images or other files. Namespace-ul în care se încarcă fişierele este de tipul :pm:prj20??:c? sau :pm:prj20??:c?:nume_student (dacă este cazul). Exemplu: Dumitru Alin, 331CC → :pm:prj2009:cc:dumitru_alin.
Jurnal
Puteți avea și o secțiune de jurnal în care să poată urmări asistentul de proiect progresul proiectului.
Bibliografie/Resurse
Listă cu documente, datasheet-uri, resurse Internet folosite, eventual grupate pe Resurse Software şi Resurse Hardware.
