i have rich experience in design and development
of GSM/GPRS based system as well WIFI/
BLUETOOTH systems...
i can develop end to end product using SIM800C,
SIM800A, SIM900, SIM7600, ESP8266, ESP12,
ESP32, HC05, HC06 with supportive power
supply design using XL6009, LM2576 ADJ, LM317
etc. with also supportive MCUS like AVR, PIC
ARDUINO, RASPBERRY PI, MEGAWIN, NUVVOTON,
SILAB, TEXAS INSTRUMENTS, ANALOG DEVICES,
CYPRESS, NATIONAL SEMICONDUCTORS, ST etc.
Also familiar with MODBUS 485 system development with any MCU.
Thanks let's discuss further to fulfill your
requirements