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 […]
Poor man’s AC230V Smart Plug v1
Recently I have received a few messages from a follower who is interested in making a simple relay box that will help him operate some regular electrical devices using the control signal from a common […]
Inverter Crystal Oscillators & A Half-Baked Project
This post describes the construction of basic crystal oscillator. The key parts in the experimental setup are a KDS4.000 quartz crystal (4.000MHz) and a SN74HC04N hex inverter IC. It should be easy to use an […]
Window Comparator Revisited
Circuit configuration of a Window Comparator usually consists of a pair of inverting and non-inverting voltage comparators in which the output indicates whether an input signal is within a voltage range defined by two different […]
Lazy LED Flasher – Learner’s Edition
Every once in a while, I have found myself needing a quick circuit to blink a light emitting diode. It is quite easy to build simple microcontroller circuits which performs this task thru a few […]
Decade Resistance Box & A Cheap Substitute
The decade resistance box is an indispensable test gear for any electronics lab as it can be used to substitute different values of resistors during prototyping and/or experimenting with electronic circuits. Using it is easy […]
Simple & Safe Adapter for Optocouplers & Solid State Relays
An optocoupler, simply put, is a little device consisting of an independently-powered light transmitter and light receiver unit packed inside a light-proof shell that can be optically coupled together. Actually optocouplers are very easy to […]
KA431/TL431 Time Delay Switch
The real inspiration for this post actually came from lots of lame designs seen on the web. The last drop was a reasonably great written article presenting a number of blueprints to build timer circuits […]
BEMF and DC Motor Speed Governors
Do you know? You can govern the speed of brushed DC motors without any additional sensors, but using a basic characteristic – the speed-dependent back EMF (BEMF) voltage! The BEMF motion control technique has been […]