VoiceAndon: Hands-Free Help for CNC Operators

CNC machines stop, and downtime is expensive: Siemens estimates unplanned downtime costs the world's 500 largest companies nearly USD 1.4 trillion a year (The True Cost of Downtime 2024). Skilled help is scarce: Taiwan's manufacturing sector had 92,000 open positions in March 2025, the most of any sector (CNA / Ministry of Labor). VoiceAndon is a hands-free voice agent for the machine operator, standing at a loud machine with oily gloves. The operator clicks "AssemblyAI Connect" and talks. The agent checks the machine, looks up the alarm code and reads back likely causes and the first three checks, so simple problems are fixed on the spot. If the problem survives, it asks for the symptom, severity and whether production can continue, reads the ticket back, and files it only after the operator says "yes"; a confirmation gate in the browser enforces this. The ticket appears instantly on the live work-order board. Under the hood, the AssemblyAI Voice Agent API handles speech-to-text, turn-taking, the LLM and the spoken reply over one WebSocket, with Voice Focus noise suppression for loud floors. Eight JSON-Schema tools run in the browser. Our server checks a demo passcode and issues short-lived tokens, and sessions are capped at five minutes. Principles: rescue first, ticket second; never invent numbers, codes or ticket IDs; never control the machine. Roadmap: low-risk actions confirmed by a person, then safe PLC commands behind hardware interlocks; the emergency stop stays in human hands. Pricing: USD 19 per machine per month. Demo data is fictional. Built by a machinery veteran (25 years, 14 in machine tools) with AI-assisted development. Try it: open https://assembly-ai-sepia.vercel.app in desktop Chrome, click "AssemblyAI Connect" and allow the microphone (passcode pre-filled). Say "Machine three has an alarm.", then "Please open a repair ticket." and answer "Yes." Console shortcuts are read aloud by the agent.