A portable, battery less weight scale powered by your smartphone’s NFC. Designed for tracking nutrition on the go
Motivation
Conventional scales are bulky and require batteries, limiting portability. The goal was to create a compact, battery-less scale readable via any NFC-enabled phone for on-the-go nutrition tracking.
Context
Bachelor’s thesis project (2025) focused on a portable, low-cost capacitive force sensor and NFC energy harvesting for weight measurement without external power.
Design goals
Battery-less operation via NFC energy harvesting
Thin, compact form factor
Low-cost materials (< $5)
Compatibility with Android and iOS NFC devices
Technical concept
Solution Highlights
Successfully draws power from NFC signal
Harvests up to 20 mW
Working custom app
Low-cost: ~$4 per unit (1000 pcs)
10 g resolution, 400 g maximum weight
The phones NFC signal is powering the circuit
