The ultrasonic hand sanitizer circuit detects the presence of human hand through reflected ultrasonic waves, and triggers a relay solenoid pump momentarily for dispensing the sanitizing liquid on the hands of the user. The project uses the popular HC-SR04 ultrasonic sensor module for the required sensing function. Using HC-SR04 The HC-SR04 ultrasonic sensor module is […]
Newly Updated Circuit Projects:
Sleeping Aid Circuit
The sleep aid circuit appears to be particularly effective when used with young children experiencing restless nights. This can, in turn, contribute to the entire household enjoying uninterrupted sleep. With the sleep aid device operating next to you, you can customize the volume and depth settings according to your mood. Then, recline and focus your […]
Transcranial Random Noise Stimulation (tRNS) Circuit
In this post I have explained a basic Transcranial random noise stimulation (tRNS) circuit diagram which can be implemented externally for stimulating brain cells, resulting in an enhanced performance of the brain. The design was requested by an avid reader of this blog “Ankita”, as given below. Design Request I’m interested in building a tRNS […]
Car Tank Water Sensor Circuit
In this article I have explained a simple car tank water sensor alarm circuit using IC 555 and a pulsating signal on the sensing probes to pevent corrosion on the probes. The idea was requested by Mr. Peter. Circuit Objectives and Requirements The Design Referring to the figure below, the proposed car tank water sensor […]
Simple 3 Phase Inverter Circuit
In this post I have explained how to make a 3 phase inverter circuit which can be used in conjunction with any ordinary single phase square wave inverter circuit. The circuit was requested by one of the interested readers of this blog. UPDATE: Looking for an Arduino based design? You may find this one useful: Arduino 3 […]
Electronic Load Controller (ELC) Circuit
In this post I have explained a simple electronic load controller or governor circuit which automatically regulates and controls the rotational speed of a hydro-electric generator system by adding or deducting an array of dummy loads. The procedure ensures a stabilized voltage and frequency output for the user. The idea was requested by Mr. Aponso […]





