Category Archives: Featured


Making a SPL dB Meter

In the 1980s, there was no internet as like today and so the sources of entertainment were televisions, radios and cassette players. When I was a kid, we had an audio cassette player. We used it to play songs but my imagination was always fixed to its VU meter display with its fancy readings as shown below. It changed with the volume of the speakers and matched rhythmically with the sound coming out of it. During my engineering career, I got to know about the Decibel scale and sound pressure measurement. It soon became a goal for me to design

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Tutorial 9: ESP8266 and WS2812B RGB LED (or NeoPixel) ring

This tutorial describes how to interface a WS2812B RGB LED ring or Adafruit’s NeoPixel ring to ESP8266. The WS2812B is a smart RGB LED with a control circuit integrated in a 5050 SMD package. The RGB data transfer occurs through a single data input line using single NZR communication mode. Connection between the NeoPixel ring and ESP8266 is through a single data wire. I am using EasyESP-1 here for illustration. The Data In (DI) line of the NeoPixel ring connects to D1 pin of EasyESP-1. VCC and GND pins go to 3.3V and GND terminals of EasyESP-1. I used a 40 RGB LED NeoPixel-compatible LED

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Programmable LED dimmer using PIC16F18325

LUKAS FÄSSLER designed a versatile programmable LED dimmer using PIC16F18325 MCU to drive white and RGB LEDs. It operates at a wide range of power supply (6 to 26 volts) and utilizes MOSFET drivers with non-inverting outputs. The mosfet drivers are basically the same as before but now with non-inverting outputs: LM5111-1M. There are two of them for a total of 4 outputs compared to only 3 with the previous version. They now drive much (physically) smaller but no less capable mosfets which allowed me to significantly downsize the whole board to 75x65mm.  The NXP BUK9Y12-40E are rated at 40

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Heart rate monitoring over the internet using ESP8266

With the rapid development and maturing of internet-of-things (IoT) technology, the IoT-driven smart sensors and systems are changing business in multiple industries. In healthcare industry, it is gaining more attention lately because of its immense potential in reducing the cost of tracking health information, as well as in providing health care to people who were not able to receive it before. This project describes a simple remote heart rate monitoring system based on the ESP8266 platform and the Easy Pulse Plugin sensor module. The ESP8266 reads in the analog photoplethysmograph (PPG) output from the Easy Pulse sensor, computes the heart beat rate in real time,

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Tutorial 8: ESP8266 Internet clock

The National Institute of Standards and Technology (NIST) provides official time in the United States. NIST disseminates the time using several methods, including radio broadcasting over short-wave and long-wave frequencies, telephone dial-in services (ACTS), and Network Time Service (NTS) over the internet. This tutorial describes how to build an ESP8266-based internet clock that uses NIST’s NTS service to retrieve accurate time information. The time is displayed on a colorful TFT LCD (ILI9341 driven) in both analog clock dial and digital formats. The time is synchronized to the NIST server in every 2-minute interval. Hardware This project uses an ESP8266 module to connect to

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