Hardware case study / KiCad 10 / Rev C

An organised interface between controller, sensors and relays.

This carrier board brings the low-voltage connections for an Arduino Mega-based incubator controller onto a compact PCB. My PCB work focuses on component placement, routing, connector access and layout verification.

CAD design checked · not assembled or bench-tested
Board outline
96 × 76 mm
Construction
2 copper layers
Layout scope
30 footprints · 4 mounting holes
Recorded review
12 September 2026
Angled KiCad 3D render showing the incubator carrier board and its connectors
A KiCad 3D render, not an assembled prototype. Select any drawing to inspect it at full size.

The design brief

Make the interface clear, accessible and checkable.

The board groups three temperature-sensor connections, four relay-control signals, status LEDs and an acknowledgement button. A keyed ribbon connector provides the controller interface; separate terminals handle the relay-coil supply. This is an interface carrier, not a complete incubator controller or a standalone safety system.

PCB decisions

Placement and routing with a reason behind them.

  • Connectors at the board edges

    Sensor terminals sit along the lower edge; coil-supply terminals sit on the right. Placement leaves room for wiring and keeps the four mounting holes accessible.

  • Different routes for different jobs

    Signal traces use a 0.30 mm width. The coil-positive route uses 1.50 mm and the main coil return uses 1.20 mm. These are design choices, not measured current-capacity guarantees.

  • A deliberate ground connection

    The logic and coil ground regions meet at the NT1 copper net tie. The actual relay module must be checked for additional internal ground connections before the complete system can be validated.

  • Mechanical checks alongside electrical checks

    The layout accounts for terminal-body setbacks, mounting-hole keepouts, courtyards and connector orientation. Physical fit still needs confirmation with the purchased parts.

Routed PCB layer view showing front copper routes, back copper pours and four mounting holes
Routed-board view from the Rev C design record. No claim of manufactured-board performance is implied.

Schematic organisation

Trace each interface before following the copper.

The schematic separates the controller header, three sensor interfaces, relay-control connections, coil-power path, indicators and acknowledgement button. This makes the relationship between the intended connections and the board easier to review.

Rev C carrier schematic arranged into labelled controller, sensor, relay, power, indicator and button sections
Rev C schematic export. Open the full-size drawing to read component values and connection labels.

Verification record

What was checked—and what those checks mean.

These results come from the saved KiCad 10.0.3 reports dated 12 September 2026. They are CAD checks, not physical test results.

Schematic electrical-rule check (ERC)
0 errors and 0 warnings reported under the saved check configuration.
PCB design-rule check (DRC)
0 violations and 0 unconnected pads reported under the saved check configuration.
Schematic-to-PCB agreement
The verification record reports 0 parity issues and 71 matching electrical pin assignments in a separate pin-map audit.
Mechanical review
Board outline, mounting-hole clearances and terminal-body positions documented. A 3D view checks model placement, not actual part fit.

The reports retain KiCad’s listed default ignored checks. A clean ERC/DRC result is not proof of functional performance, safe operation or certification.

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