From dev board to custom PCB: when to make the switch
Published 6 min readLeer en español
Short answer
Move from a dev board to a custom PCB when you will repeat the product, when the board does not fit in size, connectors or robustness, or when you need industrial I/O, 24 V supply and isolation. A custom design has an upfront cost that only pays back through volume or requirements a dev board cannot meet, and if you sell it in the EU it needs CE marking.
Key points
- Dev boards are ideal for proving an idea; they are rarely the best basis for a repeated product in an industrial setting.
- Signs it is time: repetition, size or connector problems, unit cost, supply risk, industrial I/O, 24 V and isolation.
- A custom PCB means schematic, component selection with lifecycle in mind, layout, DFM, prototypes, testing and firmware.
- Compare the development cost (NRE) with the saving per unit: do the sums before deciding.
- A useful middle step is a carrier board built around a pre-certified module.
Almost every electronics project starts the same way: an Arduino, an ESP32 module or a Raspberry Pi, a few relay modules and jumper wires. That is the right way to prove an idea. The trouble starts when that prototype stays in production, or you need to build ten more.
This article helps you decide when to move to a custom PCB and what that involves.
What is the difference between a dev board and a custom PCB?
A dev board is a general-purpose circuit: Arduino and similar, ESP32 modules, Raspberry Pi, or ready-made DIN-rail industrial I/O modules. They are designed so anyone can start without designing hardware.
A custom PCB is a board designed for your specific application. It carries exactly the components, connectors, power supply and protection you need, in the size and shape of your enclosure.
Neither is better in the abstract. The dev board wins on time and upfront cost; the custom PCB wins on fit, robustness and unit cost once there is volume.
What are the signs it is time to design your own PCB?
These are the most common signs:
- You will repeat the product or project. Hand-assembling the same tangle of modules each time is slow and error-prone.
- Size, connectors or mounting do not fit. Flying leads, modules held with tape, connectors that work loose under vibration.
- Unit cost matters. Several stacked boards and modules cost more than one circuit that integrates only what you need.
- You depend on the supply of one particular board. If the maker changes the revision or stops selling it, your product stops too.
- You need industrial I/O. 24 V inputs, transistor or relay outputs, 4–20 mA loops, RS-485.
- You need a 24 V supply. The standard in industrial panels, with all its transients.
- You need galvanic isolation between field and logic, or between communications and power.
- You need protection the dev board does not have.
If you recognise two or three of these, it is worth running the numbers.
What does designing a custom PCB involve?
A serious custom design has these stages:
- Specification. Inputs, outputs, power, communications, environment, size and applicable regulations. In writing.
- Schematic. The full circuit, including protection and power.
- Component selection. Not just on price: on lifecycle, availability from several distributors and drop-in alternatives. An end-of-life part forces a redesign.
- Layout. Component placement and routing, ground planes, isolation clearances and current paths.
- DFM (design for manufacture). So the fabricator and assembler can build it without surprises: pad sizes, panelisation, test points.
- Prototypes. Usually at least one revision fixes issues found in the first.
- Testing. Functional, temperature, power and communications tests. Ideally, EMC pre-compliance testing before the formal tests.
- Firmware. Adapted to the final hardware, with updates and diagnostics planned in.
Electronics and products work covers all of these stages, not just drawing the board.
What makes a PCB robust in an industrial environment?
A control panel is not a desk. Points to watch:
- 24 V transients. Inductive loads, motor starts and switching create spikes. The input needs suppression and filtering.
- Reverse polarity. Someone will wire the supply backwards. The board must survive it.
- Isolation. Optocouplers, digital isolators and isolated converters separate field from logic.
- ESD. Accessible connectors need protection against electrostatic discharge.
- EMC-aware layout. Continuous ground planes, small current loops, filtering at cable entries. Fixing EMC after the design is done costs far more.
- Conformal coating where there is humidity, salt or dust.
- Temperature range. Components rated for the real installation range, not just the office.
Which regulations apply if you are going to sell it?
If the product is placed on the EU market, it must carry CE marking and comply with the applicable directives. The most common for electronics:
- EMC (electromagnetic compatibility): almost always applies.
- LVD (low voltage): if the equipment operates at voltages within its scope.
- RED (radio equipment): if it includes Wi-Fi, Bluetooth, LoRa, cellular or another radio.
This means testing, technical documentation and a declaration of conformity. Set aside time and budget from the start; finding out at the end delays the launch. Equipment for internal use in your own plant has different considerations, but it is still worth designing with good practice.
How much does it cost and when does it pay back?
The key comparison is development cost (NRE) versus saving per unit. An illustrative example, with made-up figures to show the calculation:
- Dev board solution: €120 per unit (boards, modules, wiring and assembly).
- Custom PCB: €40 per unit built.
- Custom PCB development cost (design, prototypes, testing, compliance tests): €15,000.
Saving per unit: 120 − 40 = €80. Break-even: 15,000 / 80 ≈ 188 units.
| Units | Dev boards | Custom PCB (NRE + units) |
|---|---|---|
| 10 | 10 × 120 = €1,200 | 15,000 + 10 × 40 = €15,400 |
| 100 | 100 × 120 = €12,000 | 15,000 + 100 × 40 = €19,000 |
| 500 | 500 × 120 = €60,000 | 15,000 + 500 × 40 = €35,000 |
Your own figures will change the result. And there are cases where volume does not matter: if the dev board cannot meet the I/O, isolation or regulatory requirements, cost is no longer the question.
Is there a middle step between a dev board and a full custom design?
Yes: the carrier board. You design a custom PCB with tailored power, protection, connectors and I/O, and mount a commercial module on it, such as a pre-certified radio module or a compute module.
Advantages:
- You reduce the design risk of the most complex part (radio, high-speed processor).
- A pre-certified radio module simplifies part of the radio assessment, although the complete product still needs its own conformity assessment.
- You get industrial robustness where it matters: power and I/O.
If the device will talk to other systems, see also Modbus, OPC UA or MQTT: which protocol to choose.
Checklist: is it time for a custom PCB?
- I will build more than a handful of units, or repeat the project.
- The current build has flying leads, loose modules or unreliable connectors.
- I need a 24 V supply with transient and reverse-polarity protection.
- I need industrial I/O or galvanic isolation.
- I depend on a board whose supply I do not control.
- The product will be sold in the EU and needs CE marking.
- I have compared NRE with the saving per unit using real figures.
- I have considered a carrier board with a certified module as a middle step.
If you tick three or more, the switch deserves a proper study.
How we approach it at Kinetifab
First we look at what you have and what you need, and if a dev board is enough, we tell you. When a custom design makes sense, we fix the scope in writing, plan regulatory compliance from day one and hand over schematics, manufacturing files and firmware. See more on electronics and products or contact us.