Trace-detection nose module for quadruped robots

Trace detection is a real industry. Customs ports, large-event security, refineries, and pharmaceutical warehouses all use either trained K9 dogs or instrumented humans walking with handheld meters. Both have downsides: dogs need rest cycles, trainer pay, and heat tolerance; handheld humans don't cover large areas efficiently. A quadruped robot with a calibrated sensor head walks 2 km/hr indefinitely, doesn't need lunch breaks, and produces timestamped log files. For the customer organizations buying this, the addon is a cost-per-coverage-area improvement, not a novelty.

The sensor head houses a Photoionization Detector (PID — measures volatile organic compounds via UV ionization, sensitive to ppb levels) and 3 swappable electrochemical cells targeting specific compound families. Standard configurations: (a) explosive-precursor detection — TNT, PETN, ammonium nitrate; (b) narcotic detection — cocaine, methamphetamine, fentanyl; (c) industrial VOC — hydrogen sulfide, ammonia, chlorine, benzene. The cells are commodity (RAE Systems / Industrial Scientific compatible), $80-180 each, swap in 2 minutes. Calibration is a 30-second zero-air procedure performed at start of shift.

Important: this addon is sold to vetted customers (security firms, customs agencies, industrial safety organizations) under the same compliance regime as trace-detection handhelds (ITAR awareness for explosive cells in some markets). It is not a consumer product. The DIY parts list we publish doesn't include the explosive-detection cells — those require an end-user agreement we work out with each buyer separately. The narcotic-detection variant is similarly access-controlled. The VOC industrial-safety variant is openly available.