Handy Test Light (v1)

Get ready to make a high-resistance continuity tester pen that runs on a pair of common 1.5V AA batteries. This design is based on an idea from a Chinese website but with a few modifications. […]

CD4541 Programmable Timer IC Cheat Sheet

Today we are going to inspect the CD4541B CMOS programmable timer IC. The CD4541B programmable timer chip has a 16-stage binary counter, an integrated oscillator for use with an external capacitor and two resistors, output […]

Doorbell Sensor IoT Module (v1)

In this post, I will attempt to share the design idea of a doorbell sensor that can be build using just a handful of inexpensive and easily available electronics components. When cleverly integrated into your […]

4V SLA Battery Charger

Pretty little 4V Sealed Lead Acid (SLA) or Sealed Maintenance Free (SMF) batteries are widely used in portable electronic gadgets such as mosquito bats, kitchen scales, healthcare instruments, etc. The most common 4V SLA rechargeable […]