App note: Core independent voltage window signal detection using a single comparator

Presenting the usage of Core independent paripheral of PICs in this app note from Microchip. Link here (PDF) It is possible to find out whether a measured signal is below or above a certain value/reference using a single comparator. But, what if the desired interval is between two values, the undervoltage and overvoltage protection? The […]

App note: Power supply rejection ratio of low dropout voltage regulators

Here’s an app note about PSRR of LDO from Microchip. Link here (PDF) The Power Supply Rejection Ratio is the ability of a device, such as a Low Dropout Voltage regulator, to reject the various perturbations that can be found in its input supply rail by providing a greatly attenuated signal at the output. Generally, […]

Build an ESP8266 web server – Code and schematics (NodeMCU)

A detailed instructions of how to build an ESP8266 Web Server using NodeMCU firmware: This tutorial is a step-by-step guide that shows how to build a standalone ESP8266 Web Server that controls two outputs (two LEDs). This ESP8266 NodeMCU Web Server is mobile responsive and it can be accessed with any device with a browser in […]

App note: Comparison of LED circuits

Another application note from OSRAM on different LED circuit design failure mode. Link here (PDF) In recent years, Light Emitting Diodes (LEDs) have become a viable alternative to conventional light sources. The overriding advantages long life, high efficiency, small size and short reaction time have lead to the displacement, in ever increasing numbers, of incandescent […]

App note: Dimming LEDs with respect to grouping current

App note from OSRAM describing the behaviour of LEDs in respect to brightness by varying the current and to suggest solutions for avoiding negative influence for the application. Link here (PDF) In the design of a driving circuit for LEDs, the dimming behaviour is an important topic to fulfill the end customer requirements. The behaviour […]

Building a bluetooth DAC with Raspberry Pi Zero W

Sami Pietikainen has written an article detailing the build of his Bluetooth DAC using Raspberry Pi Zero W: My car comes with a built-in Bluetooth hands-free but unfortunately it does not support audio streaming. Luckily there is an AUX input available which uses a regular 3,5 mm jack. Perfect opportunity for a DIY project. I built the […]

A DIY SMD pick and place tool for electronics assembly

Here’s a DIY vacuum pick-up tool for SMD components: This video describes a DIY Vacuum Pick-up tool for picking and placing parts from an SMD component tape. The basic design for this tool involves using a vacuum pump and a solenoid to control the vacuum to a handpiece under control of a foot pedal. Via SDG […]

Looking inside a 1970s PROM chip that stores data in microscopic fuses

Ken Shirriff did teardown of a 1970s PROM chip: The MMI 5300 was a memory chip from the early 1970s, storing 1024 bits in tiny fuses.1 Unlike regular RAM chips, this was a PROM (Programmable Read-Only Memory); you programmed it once by blowing fuses and then it held that data permanently. See the full post […]

App note: Passive entry door system with proximity sensor

A full implementation of a keyless entry from Microchip. Link here (PDF) The door access systems have evolved from simple physical keys to more sophisticated keyless entry systems. Now, we have a system that automatically unlocks the door when user carrying an access key approaches the door handle. As it does not require any user […]

App note: Low Power POE Flyback Converter

App note from Microchip about their MIC2145 boost switching regulator to do POE Flayback conversion. Link here (PDF) The MIC2145 skip mode controller is used to implement a flyback converter that is intended for use in nonisolated, low power, POE applications. The circuit has a nominal 48V input and supports the POE voltage range of […]

Open source hardware ESP32-ADF

Here’s an open source hardware development board for Espressif audio development framework, the ESP32-ADF, from Olimex: With ESP32-WROOM-B module with 8MB RAM and 4MB of Flash, two microphones, two 3W speakers, codec, amplifier, Lipo charger, USB with programming, Audio 3.5mm jack, ESP32-ADF board offers everything you need to start playing with Espressif Audio Development Framework. Check […]

DC40 receiver

Michael LeBlanc has a nice write-up on building a direct conversion radio receiver: In the late winter of 2018-19, I decided to build a receiver that would provide a performance improvement to the regen I built a couple of years ago. I wanted the radio to receive AM and SSB signals between 160m and 20m […]