Wireless, battery-free electronic 'stickers' gauge forces between touching objects

https://techxplore.com/news/2023-10-wireless-battery-free-electronic-stickers-gauge.html

"polymer compresses drawing copper strips closer increasing electric charge in millimeters thin soft polymer sheet capacitor... low power, transmitting radio signals from RFID reader via backscattering... attached under box measure weight.. withstood >1K force applications... each sticker <$2 fabricated cost.. future: smartphone readable stickers eliminating need for RFID readers... robots, VR and AR, warehouse inventory management accuracy and efficiency (miniature scales), biomedical: implant's (knee) fit, wear and tear"