Yes! it is as simple as it sounds. You can build your own Phone using SIM800L module and Arduino Nano. You are free to use any SIMcom version of GSM module and any version of Arduino. The Program I have written can be used with any combination as long as pin configuration is same.
All you need- Arduino Nano
- SIM800L module
- 3.7v 1200mah Li-ion Battery
- TP4056 Battery Charging Module with Protection
- LEDs and 1K Registers (choose correct register for a LED)
- PAM8403 5V Digital Audio Amplifier Module (optional)
I have custom printed a multi purpose PCB for projects like this. But you can do it on bread board also. The connection diagram will be same as follows compatible with my written Program.
If you are really interested in how there are some links to checkout below
