Know what to do next with your product idea.
You’ve got an idea you believe in. The Free Sprint turns it into two quick-draft documents you can build on: a Specification you can hand to any engineer, and a Viability Report covering market potential, opportunities, challenges, timeline and cost. About 15 minutes. You decide what to do next.
Stuck between an idea and a build.
PROBLEM · WHERE IDEAS STALLMost product ideas die in the gap between “I have an idea” and “I know what to build”. Weeks of research that goes nowhere. Conflicting advice from people with skin in the game. Five-figure prototype costs proving the wrong thing first.
Built for physical products. Things that get made, packed, shipped. Not apps. Not services.
Built by the engineer behind 280+ products.
GUIDE · WHO BUILT THIS · 15 YEARS
Dave Lock has spent 15 years engineering physical products at Cast Iron CAD: consumer goods, industrial plant, bespoke builds. Products in people’s homes and on factory floors today. He also teaches product design and manufacturing at the University of Brighton.
Innovate Engineer distils that methodology into structured tools, so the same discipline is available without a paid consultation. The Sprint is the same conversation he’d run in a paid review, scripted and pressure-tested against real manufacturing constraints.
One continuous path. Two phases.
FRAMEWORK · WHERE WE WORK
The Free Sprint is the first pass through the early stages (sub-activity 01.04) and produces the Specification and Viability Report. The full 10-stage framework, what happens at each stage, and where AI stops and people start is on the How It Works page.
Not a scorecard. A structured interrogation.
MECHANISM · WHAT THE GPT DOESFair question if you’re visiting cold: is this just ChatGPT with a prompt template? No. The Sprint runs the same ordered path we use on paid engineering projects, enforces it turn by turn, and won’t let you skip the hard questions.
Structured questions through stages 01 to 05.
Problem framing. Customer. Requirements (must, should, could). Concept. Specification. Vague answers get pushed back.
Not: an open-ended chat. Is: a staged interview you can’t short-circuit.
Against the 10-stage framework above.
Your answers are pressure-tested for manufacturability, cost bands, timeline plausibility, and failure patterns from 15 years of real project work.
Not: generic internet advice. Is: our methodology, compressed.
Two portable documents. Yours to keep.
A Specification any engineer can quote against, and a Viability Report showing where the idea is strong, where it’s weak, and what to test next.
Not: a hosted dashboard. Is: files you own, no account needed.
What you walk away with.
OUTCOME · WHAT YOU KEEPThe source of truth for the idea.
- Product concept statement
- Prioritised requirements (must / should / could)
- Structured product specification
- Copy-ready – paste into any brief or deck
Direction, not a verdict.
- Brief summary and spec summary
- Market potential read
- Opportunities and challenges
- Timeline estimate and potential cost bands
Four packages. Start free. Go deeper only when it earns its keep.
PACKAGES · FIXED FEEFree Sprint
A fast, AI-guided interview through stages 01–05. Produces a quick-draft Specification and Viability Report, copy-ready to refine before you brief an engineer. Full mechanism on the Viability Sprint page.
- Structured step-by-step interview
- Viability: strengths, risks, next step
- Market potential & challenges
- Must-have vs nice-to-have features
- Timeline and cost bands
- Copy-ready Specification & Viability Report
Engineer-Verified Review
A working engineer reviews your sprint output, sharpens the numbers, flags what AI missed, and gives you a clear viability assessment.
- Everything in Free Sprint, plus
- 30-minute engineer video review
- Refined cost estimates (supplier-informed)
- Risk flags AI may have missed
- Manufacturing method recommendation
- Written summary within 48 hours
Expanded Specification
Your sprint and review output transformed into a professional, branded specification document – ready for investors, manufacturers, or engineering teams.
- Everything in Engineer Review, plus
- Branded Product Specification (.docx)
- Prioritised requirements summary
- Design Brief document
- Investor / funder-ready formatting
- Engineer-ready formatting
Handover-Ready Package
A dedicated handover session with a custom development roadmap, manufacturing strategy, and direct introduction to the engineering team.
- Everything in Expanded Spec, plus
- 1-hour specialist consultation (video)
- Custom development roadmap
- Manufacturing strategy & method selection
- Supply chain considerations
- Direct Cast Iron CAD team introduction
- Priority engineering quotation
ALL PAID PRICES INC. VAT · FIXED FEE · NO SCOPE SURPRISES
Questions people ask before starting.
FAQ · BEFORE YOU STARTIs it really free?
Yes. No payment, no sign-up, no lead-nurture sequence. If you want a human to review the output with you, that is the £129 Engineer-Verified Review – separately, only if you want it.
How long?
About 15 minutes for a complete quick-draft Specification and Viability Report. It’s designed as a first-pass – enough to decide what to refine, what to brief, or whether to move on. Add detail yourself, or hand it to an engineer for the £129 Engineer-Verified Review.
Who is it for?
Founders, inventors, and pre-launch creators with an early-stage physical product idea. Not apps. Not services. Things that get made, packed, and shipped.
Who sees my idea?
Your session runs inside a custom GPT on your own ChatGPT account. We don’t see or review individual sessions. If you book the Engineer-Verified Review, you choose what to share and when.
How accurate?
The sprint returns confidence-rated ranges, not single figures. Directionally useful for shaping the next decision. The paid Engineer-Verified Review narrows them using real manufacturing data.
What if it fails?
That is the point. Finding out early, before you spend on CAD or tooling, is the win. You keep the Specification and Viability Report either way and can come back when the idea matures.
If it’s not for you, close the tab.
No payment. No sign-up. No sales call. Keep whatever’s useful, come back when the idea matures. Nothing to cancel, nothing to undo.