Definition of Done for Hardware Components: It's Not "Done" Until It Ships
Quick Summary: Key Takeaways
- Ban "99% Complete": In hardware, "almost done" usually means "untested." If it hasn't passed the test, it isn't Done.
- Fidelity Matters: The definition changes based on the stage. "Done" for a prototype is different from "Done" for a mass-production unit.
- Compliance is Mandatory: Safety checks and certifications (UL, CE) must be part of the criteria, not an afterthought.
- No "Over-the-Wall": A component isn't done until it integrates successfully with the system, including firmware.
The "90% Done" Illusion in Manufacturing
In software, you compile the code. If it passes the test suite, it is "Done."
In hardware, teams notoriously report tasks as "90% complete" for weeks. They have the CAD drawing, so they think they are finished.
But a drawing is not a product.
To stop this perpetual delay, you must establish a rigorous definition of done for hardware components. This contract ensures that no piece of metal or silicon leaves a sprint until it meets specific, verifiable criteria.
Note: This deep dive is part of our extensive guide on Agile for Hardware Development: The Ultimate Guide to Iterating on Atoms.
Defining "Done" Across the Fidelity Ladder
A single Definition of Done (DoD) cannot cover the entire lifecycle of a physical product. You need tiered definitions based on the fidelity of the prototype.
If you apply mass-production standards to a cardboard mockup, you will never ship.
1. Concept Stage (The "Looks-Like" Model)
- Goal: Validate ergonomics and form.
- Definition of Done:
- 3D print or foam model assembled.
- Physical dimensions match the interface document.
- Stakeholder review completed.
2. Engineering Validation (The "Works-Like" Model)
- Goal: Validate function and durability.
- Definition of Done:
- Component functions under load for X cycles.
- Thermal stress test passed (no overheating).
- Embedded testing requirements are met (firmware successfully controls the hardware).
3. Production Validation (The "Made-Like" Model)
- Goal: Validate manufacturability.
- Definition of Done:
- Tooling verified (molds produce parts within tolerance).
- Supply chain confirmed (vendors locked).
- Compliance certifications (FCC, CE) passed.
The Hardware Sprint Review Checklist
When a mechanical engineer brings a gear to the Sprint Review, the team must ask: "Is it Done?"
Use this checklist to avoid ambiguity:
- Is it in the repository? (CAD files committed, version controlled).
- Is it physical? (Simulation is good, but is there a physical artifact?)
- Does it fit? (Integration test with mating parts passed).
- Is it legal? (Material compliance, e.g., RoHS, checked).
Frequently Asked Questions (FAQ)
What does a DoD look like for a circuit board?
For a PCB, "Done" usually includes: Schematic capture complete, layout DRC (Design Rule Check) passed, bill of materials (BOM) validated for availability, and board bring-up test (smoke test) passed on the physical prototype.
Is a CAD drawing considered "Done"?
No. A CAD drawing is a design artifact, not a product increment. In Agile hardware, "Done" implies a tangible validation. If the task is "Design the Chassis," the DoD should be "Chassis simulated and 3D printed for fit check," not just "File saved."
How to define "Done" for a prototype vs final product?
Use "Exit Criteria" for each development phase. A prototype is Done when it proves a hypothesis (e.g., "The fan cools the CPU"). A final product is Done when it is shippable to a customer (packaging, manual, and regulatory stickers included).
Checklist for hardware sprint review.
1. Component physically present. 2. Verified against acceptance criteria (e.g., "Weight < 50g"). 3. Known bugs documented. 4. Integration test with software/firmware passed.
How to handle compliance testing in DoD?
Compliance often takes weeks, longer than a single sprint. To handle this, break compliance into smaller chunks. "Done" for Sprint 1 might be "Pre-compliance scan passed." "Done" for Sprint 4 might be "Final certification paperwork submitted."
Conclusion: If You Can't Ship It, It's Not Done
Ambiguity is the enemy of velocity.
By enforcing a clear definition of done for hardware components, you force your team to confront reality early.
You move from "I think it will work" to "I have tested it, and it works." In the unforgiving world of atoms, that difference is everything.