In this post I have explained an office call bell network circuit for office complexes which could be used for calling and monitoring office member’s attendance and response from the particular intended office chamber. The idea was requested by Mr. Rajib Banerjee Technical Specifications Need a perfect useable circuit idea for Ringing the Bell as […]
Monitor
Make an LED AC Voltage Indicator Monitor Circuit
The LED AC mains voltage level indicator is a circuit that can be used for displaying and monitoring the instantaneous voltage level of any 220 V or 120 V mains home AC input, through a correspondingly rising and falling LED bar graph. A simple construction and accurate result are the main features of this tiny […]
Child Crying Monitor Circuit using Power Line Communication
In this child crying monitor circuit when the baby wakes up in their room, the parents are immediately notified, even if they are in another room of their home. A sensor detects the crying sound accompanying the wake-up. After appropriate processing, it sends a signal through the 220V power lines. The receiver, connected to any […]
Extremely Low Frequency (ELF) Radiation Monitor Circuit
ELF stands for Extremely Low Frequency, which is an electromagnetic radiation generated by most of out household electrical equipment. Regarding the effect and severity of ELF fields on human health, debate remains heated. However, I believe there is enough data for us enthusiasts to adopt a conservative stance on the level of exposure we must […]
Ni-Cd Low Battery Monitor Circuit using Lambda Diode
The main feature of this lambda-diode low battery indicator for Ni-Cd batteries is that, the circuit itself consumes almost zero current, until the set low threshold level is reached and the indicator LED is illuminated. This feature makes the circuit very suitable for many low voltage battery operated systems, like radios, watches, timers, alarms, remote […]
Heart Rate Monitor Circuit
In this article I will comprehensively discuss a relatively accurate electronic heart rate sensor circuit processed by a few discretely wired opamp circuit stages, and subsequently we’ll learn how this can be modified for making a heart rate monitor alarm circuit. Using IR Photodiode Sensors The sensing of the heart pulses is basically done by […]