Custom PCB for Low-Power IoT Sensor

PCB Design Project Brief Custom PCB for a Low-Power IoT Environmental Sensor Device Project Overview We have a fully working, bench-validated prototype of a small, battery-capable IoT sensor device, currently built on a development board and breadboard. We need a custom PCB designed around the existing, already-proven circuit so the device can move from prototype to a compact, manufacturable, professionally assembled product. This is a schematic capture and PCB layout engagement. The electrical design (which components, how they connect, and the firmware) is already complete and tested — you will not be designing the circuit from scratch, but translating a working reference design into a manufacturable PCB. What You Will Receive to Start ● A complete list of components with part numbers (module, sensor interface IC, connectors, power components). ● A description of every required connection (equivalent to a netlist) between components. ● Photos and/or a wiring diagram of the current working breadboard prototype. ● Target enclosure dimensions (if applicable) or a note that dimensions are flexible within reason. Scope of Work Deliverable Description Schematic capture Full schematic in KiCad (preferred) reflecting the provided component list and connections. PCB layout Component placement and routed copper layout, sized to fit the target enclosure dimensions if provided. Design for manufacturability Selection of footprints/parts compatible with a turnkey PCB assembly service (e.g., JLCPCB), favoring commonly stocked components where equivalent substitutes exist. Manufacturing files Gerber files, drill files, bill of materials (BOM) in assembly-service-ready format, and a component placement (CPL/pick-and-place) file. Design review call One video call to walk through the schematic and layout before final files are generated, to confirm all connections match the provided reference design. Key Technical Requirements: Just three components (2 Sensors and 1 Microcontroller) ● Microcontroller: a pre-certified WiFi-capable microcontroller module (module and part number will be provided) — must be included as a module, not a bare chip, to preserve existing radio certification. ● Sensor interface: one SPI-connected sensor-to-digital converter IC, plus a separate 1-Wire digital sensor input, each with its own connector for an external probe. ● Power: support for both USB-C input (for charging/programming) and a small rechargeable battery, with appropriate charge-management and protection circuitry. ● Connectors: a keyed, multi-pin connector for the sensor probe cable (a connector family will be specified); USB-C for power/data. ● Programming/debug: the module's native USB or a simple header must remain accessible for firmware flashing during and after assembly. ● Indicators: one status LED and one small pushbutton (e.g., for a factory-reset function) are sufficient. ● Target size: as compact as practical while keeping all connectors accessible from the enclosure exterior (exact envelope to be discussed). What Is Explicitly Not in Scope ● Firmware development (already complete). ● Mechanical enclosure design (may be a separate, future engagement). ● Circuit design or component selection from scratch (the circuit is already defined and proven). Ideal Candidate ● Demonstrated experience taking a proven breadboard/prototype circuit to a manufacturable PCB (portfolio examples welcome). ● Comfortable with KiCad (preferred) or willing to deliver final files in a KiCad-compatible open format. ● Experience preparing designs specifically for turnkey assembly services (JLCPCB, PCBWay, or similar) and familiarity with their component libraries and file requirements. ● Experience with small battery-powered, low-power / sleep-mode IoT devices is a strong plus. ● Comfortable working from a provided component list and connection description rather than an existing schematic file.