Bicycle back Safety Light

This is a circuit of bicycle back safety light. Feature : 13 LEDs flashing, 3V supply voltage, Simple circuitry, low voltage, high efficiency, battery powered. Component : Resistor, capacitor, LED, switch, battery, 7555 timer IC. [redcircuits.com]

Water-level Alert

The following circuit is a water level alert. Feature: Simple circuitry, low voltage, 1.5V supply voltage, portable unit, battery powered, low current consumption. Component : Resistor, capacitor, LED, 1N5819 diode, 7555 timer IC, piezo sounder, Battery. (redcircuits.com)