Your first custom PCB, from breadboard to five prototypes

Move from a breadboard to a custom PCB when the next question depends on the board itself. You may need to fit an enclosure, replace fragile jumper wires or give several people identical hardware. If you are still choosing the sensor or changing the basic interaction every day, another breadboard iteration may answer your questions with less rework.

The first PCB should preserve the behavior you understand while making the uncertain parts easy to inspect. A smaller board is useful only if you can still program, measure and debug it.

Capture the working setup

Photograph the wiring, but also write down the connections. Record the exact development-board and module versions, firmware revision, supply voltage and attached peripherals. A photo cannot reliably explain a hidden jumper or a pin assignment that changed during debugging.

Separate the parts of a development board you need from those you have been using without noticing: power regulation, reset controls, a programming connection and status indicators. Decide explicitly which functions move onto the PCB and which remain external.

For a wireless module, include its exact part number and intended position in the enclosure. Espressif's ESP32 layout guidance explains why antenna placement relative to the carrier board matters. Follow the documentation for your particular module rather than copying a visually similar footprint. Source checked: 2026-10-19.

For an Arduino-based setup, compare a shield, a module carrier and a fully integrated board in the Arduino-to-custom-PCB guide. For an ESP32 module, use the module-specific requirements checklist to prepare the handoff.

Write a brief someone else can review

Send these items together:

• Purpose: the behavior the prototype must demonstrate and what is outside this revision.
• Power: input-voltage range, source, expected loads and operating modes.
• Interfaces: connector part numbers, pin assignments, signal levels and cable direction.
• Mechanical limits: outline, mounting holes, maximum component height and enclosure drawing.
• Parts: exact modules or chips that must remain, with allowed substitutions identified.
• Firmware: who supplies the test build, how it is loaded and what output indicates success.
• Acceptance: observable checks with limits, duration and required equipment.

“Read a sensor” is incomplete. An illustrative requirement might be: “Read the specified sensor once per second, report its identity and readings over the debug connection, and signal a disconnected sensor.” This describes intended behavior; it is not a claim that a board has passed a test. Measurement accuracy would need a separate reference, procedure and acceptance limit.

Review the draft as a user of the board

Check whether plugs can be inserted after installation, mounting screws can be reached, and labels identify the connectors you will touch. Confirm how a board with blank firmware gets programmed. Keep accessible measurement points for the rails and signals named in the test plan.

An engineer should review the electrical design and manufacturing constraints before fabrication. Read the review checklist and resolve its open questions before approving a revision. Record the approved schematic, layout and BOM together so an older file cannot silently become the manufacturing input.

Confirm the order and the handoff

Ohmbo's Proto Kit is $149 for five eligible low-voltage DC, two-layer boards: 1.6 mm FR-4, green solder mask, up to 100 × 100 mm, single-sided SMT, up to five through-hole components per board and a $10-per-board component allowance. Four- or six-layer designs need manual review and a separate quote. Shipping and import duties are extra, confirmed before payment.

Each account gets one online design preview. Downloads become available after payment confirmation and order release. Orders are manually confirmed; shipment is 10–15 working days after engineer approval, followed by courier transit.

Agree on written test procedures, test firmware and acceptance criteria for every board, with a per-board report. On receipt, match board identifiers and revisions to those reports before starting your own application experiments.

See support for startup prototypes and the order stages. The board library contains design demonstrations, not evidence of completed physical tests. MCP is not deployed; the MCP page is a status reference, not a verified connection tutorial.