I haven’t made any project changes yet — the schematic is still empty (0 components, 0 nets). I’m currently blocked from executing design work in Flux because the session has no remaining credits.
For your pet GPS/SIM tracker, the remaining work is:
Define requirements
Pet size/weight limit for the device
Target country/cellular network
GPS update rate: real-time, every few minutes, or on demand
Battery size/weight acceptable for dog/cat collar
Waterproofing level
Select architecture
LTE-M/NB-IoT or 4G cellular module with SIM/eSIM
GNSS/GPS module or cellular module with integrated GNSS
Microcontroller for control/app commands
Audio codec/amplifier, microphone, and speaker
Li-ion/LiPo battery charger and protection
Power management sized for one-week battery life
Important feasibility note
“Exact location” is not always possible indoors; GPS works best outdoors.
One-week battery life with GPS + SIM + two-way audio is possible only if the device sleeps most of the time. Continuous live tracking and voice calls will drain the battery much faster.
For a cat-sized collar, battery size is the hardest constraint.
Next design steps when credits are available
Create project specification and power budget
Choose cellular/GPS/audio/power ICs from datasheets
Build the full schematic with SIM, antenna, GPS, microphone, speaker, charger, battery, and programming connector
Run electrical review
Create PCB layout with antenna keepouts
Add firmware/app interface notes for commands like “feed time” sound playback
Recommended starting architecture: LTE-M/NB-IoT cellular module with GNSS, low-power MCU, MEMS microphone, small speaker amplifier, LiPo battery, USB-C charging, and a mobile app backend for location + voice/audio commands.