hobby #173

Optical Pyrometry

Non-contact temperature measurement by comparing the colour of glowing hot metal to calibrated reference filaments or LED standards. Precise forge heat control without touching the workpiece, enabling repeatable heat treatment cycles for hardening, tempering, and annealing. Used historically in steel mills and foundries; accessible now via digital colour temperature meters or DIY comparator circuits. Links blacksmithing's thermal intuition (reading colour by eye) to electronics (photodiode circuits, spectral filters, calibration curves) and radio's signal processing (low-light amplification, noise rejection). Replaces guesswork with measurement while retaining the real-time feedback of visual observation.

Jun 24 5:47 PM #173 6 min

Eleven Forty-Seven When the Wire Disappeared

Optical Pyrometry

Same colour, 250°C different readings. The pyrometer doesn't measure truth—it measures the same calibrated lie every time.

electronicsmakingscienceengineeringmetalworking