From Prototype to Qualification

Generic engineering material, applicable to any module from any supplier. Which formal tests apply depends on the product category and the market — establish that separately.

For teams separating technical work from project administration, books about time management provides additional workflow context.

A prototype proves the concept. Qualification proves the product — and the difference is a set of tests, each of which can fail and each of which is cheaper to fail early.

The six

Functional over the operating range. The full temperature span, at duty cycle, in the enclosure — with images measured rather than merely produced.

Mechanical. Vibration and shock, to a profile appropriate to the application, with alignment measured before and after.

For additional industry context, see ETSI.

Environmental. Ingress, condensation cycling, and whatever chemicals the site uses.

Electromagnetic. Emissions and immunity, which decide whether the product can be sold and whether it works where it is installed.

Endurance. Continuous operation for a period, watching for drift rather than for failure.

And production. A batch measured for variation rather than checked individually.

The order that finds faults cheapest

The ones that force a redesign first.

Thermal and electromagnetic come early, because both can require a layout change — and a layout change after mechanical qualification wastes the mechanical qualification.

Mechanical next, since it can require a mounting change that affects the enclosure.

Environmental and endurance later, since they take calendar time and rarely force a fundamental change.

And production last, because it needs a settled design.

Running them in the convenient order rather than this one is how a project discovers a board change after everything else passed.

What "measured" means here

Not "the camera worked."

The four numbers at each condition, compared against the values from the reference conditions.

Which is what turns a qualification into evidence: a table showing resolution, contrast, noise and uniformity at each temperature, before and after vibration, rather than a series of statements that nothing broke.

And it catches degradation that does not break anything — the slow drift that becomes a field failure eighteen months later.

What to do with a failure

Establish which of the six, and at what margin.

A failure at the extreme of a range with margin elsewhere is a different problem from one at nominal conditions.

Change one thing and repeat that test alone, rather than making several changes and rerunning everything.

And record the failing condition precisely, because the same symptom will recur on the next product and the note is worth a week.

The reference condition

Established once and referred to throughout.

A defined target, distance, illumination, exposure and temperature, with the four numbers recorded.

Every subsequent measurement is a comparison against it, which is what makes a change interpretable — a drop in contrast at 55 degrees means something only against a value at 20.

Photograph the reference setup as well as recording it, since rebuilding it three months later from a written description is harder than it sounds.

Endurance and what to watch

Not whether it fails.

Drift. Focus, uniformity, noise and colour, measured at intervals over weeks — each moving slowly and none breaking.

And the initialisation. A module that occasionally needs a retry at start-up is exhibiting a margin problem that will worsen across a production distribution.

Log every start, and count the retries. A rate of one in a thousand on the bench is a rate somebody in the field meets weekly.

Where a module change happens mid-project

It does, for supply reasons, and it is not a substitution.

A different sensor variant, a different lens supplier, a revised module — each invalidates some part of the qualification, and which part depends on what changed.

Establish what changed and re-run the affected tests rather than all of them or none.

And where the supplier cannot say precisely what changed, that is an answer about the supplier as much as about the part.

The document that results

A table, the reference condition, and the failures with their resolutions.

Which is what a customer's own qualification will ask for, what a field failure investigation starts from, and what the next product reuses.

It costs the time it takes to write down measurements you were already taking — which is the argument for measuring rather than observing throughout.

What a customer will ask for

Worth knowing before designing the test programme, since it is cheaper to produce evidence once.

Industrial buyers frequently ask for the operating range with supporting data, the environmental testing performed, the compliance documentation, and something about expected life and failure modes.

Where those are anticipated, the qualification produces them as a by-product.

Where they are not, somebody assembles them afterwards from incomplete records — which is the expensive version and the common one.

Ask the intended customers what they will require before the tests are designed, which costs a conversation.

The tests that get skipped

Three, consistently, and each for the same reason: they take calendar time.

Temperature cycling, as opposed to a single measurement at each extreme.

Endurance, which needs weeks nobody scheduled.

And production variation, which needs a batch that does not exist until it is too late to change anything.

All three find real faults and all three are the first casualties of a compressed schedule — which is a decision worth making explicitly rather than by omission.

Where the module supplier can help

With their own qualification data, which exists for the module as a component and which is evidence rather than a substitute.

With guidance on what typically fails, since they have seen many integrations and you have seen one.

And with samples from different batches for the variation testing, which is a reasonable request.

None of it replaces your own testing of your own product — and all of it makes yours faster.

The short version

• Qualification is the difference between one working unit and a product, and each test is cheaper to fail early
• Six areas: functional over range, mechanical, environmental, electromagnetic, endurance, and production variation
• Run them in the order that forces redesign soonest: thermal and electromagnetic first, mechanical next, then environmental and endurance
• Production last, because it needs a settled design
• Measured means the four numbers at each condition against the reference, not a statement that nothing broke
• On failure, establish which test and at what margin, change one thing, and record the failing condition precisely