I did many projects with Arduino, Atmel, PIC, ESP8266 & used SIM800 for GSM/GPRS/3G. Firmware upload via microUSB (Arduino) or OTA (ESP8266). To maximize battery, MCU must be in sleep most of the time
Relevant Skills and Experience
Electronic design with Eagle, Microcontroller programming in C/C++, HTML, CSS, JavaScript, NodeJS, PHP and Google/AWS cloud.
Proposed Milestones
kr8000 SEK - This is the initial cost and it can be changed when requirement is clear
GSM module consumes a lot of battery. To submit data every 10 minutes while keeping battery last 8-10 months => need to relay using RF to a base first.