Overview
Today, portable power banks have become an essential tool for hikers. Compared with older storage batteries, both functionality and portability are far superior. For outdoor use, several features are necessary. Safety is a priority during outdoor travel, and protecting personal belongings from theft is critical. A reliable alarm system helps protect belongings, especially during camping, where a sensitive anti-theft measure is effective at night.
Alarm circuit
How can a portable power bank be designed with an outdoor alarm function? As shown in the diagram, when the pre-alarm button is pressed, the USB output voltage is applied to the alarm system, putting the power bank into a "pre-alarm" state. If the mercury switch B1 moves from its normal open position, the relay activates, driving the KD9561 musical unit to sound an alarm and alert the user.
Lighting function
A high-brightness lighting function is also indispensable for outdoor activities, especially at night. The diagram includes a related circuit design for a high-brightness night light. The USB output provides 5V, which, together with a high-brightness LED and a small current-limiting resistor, forms the lighting circuit. The LED provides sufficient illumination for distances up to about 5 meters.
