Abstract: Dual mode energy harvesting methods and portable devices that use a combination spring-type piezoelectric and electromagnetic transducer contained in a hollow casing or housing with first and second insulated, coil-shaped wire springs coated with a conductive surface electrode and piezoelectric material separated and connected at opposing ends by a movable proof mass comprising a high magnetic field strength rare earth magnet that to generate harvest energy from human motion, including walking jogging, running, and jumping, to charge external devices that include, for example, cellphones, smartphones, fitness bands, electronic readers, tablet computers, digital cameras, smart eyewear, and wearable cameras.