Requirement
Charge USB devices by the sun
Capture energy during the day even if target device is not plugged in
Materials
Switching Regulator $4
Solar panel $70 (1/3 of $200) – had these laying around – could have gone smaller
USB hub ~$2
USB battery pack ~$10
wire to solar panel (included in panel)
USB cable to battery pack
solder
Velcro with adhesive
Design
Inspired by this Instructable
Plug in to the USB hub to charge or power devices.