PCB & Embedded Systems Engineer – Secure Wireless Pump Shutdown System (900 MHz + Cellular)

I am seeking an experienced PCB design and embedded systems engineer to help design a secure, industrial wireless pump shutdown system intended for remote oilfield, irrigation, and water applications. This is a prototype / product-development project, not a hobby or consumer IoT device. Project Overview The system consists of: A Master radio that monitors digital inputs (e.g., high fluid) One or more Slave radios that actuate a relay to shut down pumps or engines License-free 900 MHz wireless communication (long range 3-5 Miles with Proper Antennas) 2 Power Options 1) AC Power Module and 2) DC Power Module with Solar Charger & Battery Connections Cellular alerting for monitoring and supervision Key Technical Requirements 902–928 MHz ISM band (FCC Part 15) Secure pairing and encrypted RF messaging Point-to-multipoint communication (Master → multiple Slaves) Industrial relay outputs Heartbeat supervision and fail-safe behavior Two power variants: 12/24 VDC with integrated solar charging (AGM battery) 120 VAC using isolated AC/DC module LTE-M or LTE Cat-1 cellular module for SMS alerts Ideal Background PCB design for industrial or embedded products RF module integration (900 MHz ISM preferred) Power electronics (DC/DC, solar charging, battery systems) Industrial I/O (relays, surge protection, grounding) Experience with KiCad, Altium, or Eagle Oil & gas, water, or remote telemetry experience is a strong plus Deliverables Schematics PCB layout (Gerbers + native files) BOM with part numbers Bring-up and test notes Power and RF design documentation Apply tot his job