“All-in-one” hydrolyzed keratin protein-modified polyacrylamide composite hydrogel transducer

•Hydrolyzed keratin endowed hydrogel with excellent adhesion for seamless contact.•The hydrogel exhibited high transparency for visible human-machine interfaces.•Anti-freezing and non-drying ability of hydrogel was achieved.•Hydrogel with high sensitivity served as transducer for monitoring human motions.