• Crystal radio set up( one popular type is antenna coil and inductive tuning coil [ no antenna is also possible ], speaker is usable without outside power) has wide band harvesting capability & many home made large device can have much higher than micro device harvesting capability.
• Some focus on increasing power by Ultra-broadband EM induction or Piezo- Electromagnetic or multiple vibration mode EM induction, etc( EnerBee +)
• HIGH VOLTAGE POWER LINE scavenging: Near field high power line ' s EM field flux directly or, Additionally generating vibration with interaction of device magnet with EM field to harvest extra energy from piezoelectric effect( Hosseinimehr & Tabesh +) etc, for self powered electric current transmission monitoring purpose: mostly Wireless Powerline Sensor( Sentient Energy IBOLT, USi Power Donut +), low power amp working( Aclara Tollgrade LightHouse), or advanced monitoring( INCON GridSense Line IQ, Lindsey Transmission Line Monitor +): This application is full mainstream use in some regions / industry power monitoring segments while almost none in others-- > cont: