by Peter Demchenko @ edn.com:
The purpose of this Design Idea was to improve reliability, add new features, and replace a latching power switch with a momentary one.
The features are:
The switch has foolproof protection against too frequent switching, which can be harmful for many applications.
It can handle significant power because manual control and switching are separated.
If an unexpected power outage occurs, the switch disconnects and remains off after power returns.
A unit can switch itself off.
Momentary switch controls mains with latch-on and remote shutdown - [Link]
This is a quick project for a timer. Recently I finished my UV light exposure box and thought that it will be convenient to have a build in timer to switch off the light after preset time. So I had a PIC16F628A lying around and after searching the web I found a Brazilian site (I think?) with tons of interesting projects with microcontrolers. This project is based on one of them.
The schematic uses the internal oscillator of the microcontroller which is enough accurate for my purposes, but as the pins 15 and 16 are left unoccupied, there can be connected external quartz resonator with better accuracy. As I said, this project is based on an existing project, but actually my schematic is quite different and the code was almost completely rewritten. My programming abilities are little rusty, but I think the final result is quite good.
Simple timer with PIC16F628A - [Link]
by Solarcycle @ instructables.com:
Power Stacker is a portable, modular, USB rechargeable lithium-ion battery pack. Stack them together for power hungry projects or separate them for smaller projects with this modular system. The Gerber, BOM, and .STL files are available below.
Power Stacker does what other USB rechargeable batteries have failed to do, and that’s the ability to combine together for increased battery capacity or separate in to many small batteries for smaller projects. You can literally use the same Power Stacker batteries for many years across many applications!
Stackable USB Rechargeable Battery System - [Link]
by Susan Nordyk @ edn.com:
Leveraging Linear Technology’s Silent Switcher architecture and spread- spectrum frequency modulation, the LT8640 synchronous step-down switching regulator reduces EMI/EMC emissions by more than 25 dB—even with switching frequencies in excess of 2 MHz—enabling the part to easily pass automotive CISPR25, Class 5 peak limits. Synchronous rectification achieves efficiency as high as 95% with a switching frequency of 2 MHz, while the part’s 3.4-V to 42-V input range makes it useful for both automotive and industrial applications.
Step-down switching regulator minimizes EMI/EMC - [Link]
by Susan Nordyk @ edn.com:
International Rectifier’s IRFH4257D is a 25-V dual N-channel power MOSFET housed in a 4×5-mm PQFN power-block package aimed at 12-V input DC/DC synchronous buck applications, such as telecom equipment, servers, graphic cards, and computers. With this latest power-block addition, designers now have the option of choosing a 4×5-mm or 5×6-mm PQFN to suit their design requirements.
Dual MOSFET squeezes into PQFN package - [Link]
by dany @ elecfreaks.com:
Smart RGB LED Strip is based on the development of our BLEduino, using the Bluetooth 4.0, and the sample code written by EF men, by mobile phone APP, to control the switch of RGB LED strip, and the RGB LED color changing. The main principle is that using BLEduino mega328P chip three PWM pins respectively to control the RGB LED strip of R G B three colors. When the phone APP and BLEduino bluetooth pairing connection succeed, phone APP can control mega328P chip three PWM pins output value, then control the the color of the RGB LED strip
Smart RGB Strip with BLEduino DIY Guide - [Link]
Kerry Wong writes:
Latching relay (a.k.a. impulse relay) can be turned on and off by momentarily applying a voltage across the relay coil. The relay would maintain in its last switched state without the need to maintain the coil current. In this post, I will show a simple circuit which can be used to drive such relays. In the video towards the end, I also included more explanations and some demonstrations.
The relay I am using here is a latching RF relay. It is used to switch the input signal between its two outputs. For this particular relay, the input has an APC-7 connector. One side of the output has an N connector and the other side is 50 Ohm terminated. Although this relay is an RF relay, the method I described below is applicable to any latching relays.
Many dedicated ICs (such as MAX4820, MAX4821) can be used for driving such relays. Because of nature of the latching relay, no H-bridge is needed (although you can definitely use an H-bridge, but it would be wasteful).
How to drive a latching relay - [Link]
Microchip Technology Inc. announced from the SPS IPC Drives Conference in Germany a new family of 16-bit dsPIC33 Digital Signal Controllers (DSCs) with the dsPIC33 “EV” family. This new family provides 5V operation for improved noise immunity and robustness, ideal for devices operating in harsh environments such as appliance and automotive applications. The dsPIC33EV family is the first dsPIC DSC with Error Correcting Code (ECC) Flash for increased reliability and safety. For safety-critical applications, the dsPIC33EV devices also include CRC, Deadman Timer (DMT), and Windowed Watchdog Timer (WWDT) peripherals as well as a backup system oscillator and certified Class B software.
Microchip Introduces New 5V dsPIC33 “EV” Family for Enhanced Noise Immunity and Robustness in Harsh Environments - [Link]
by Martha Heil @ umdrightnow.umd.edu:
Researchers at the University of Maryland have invented a single tiny structure that includes all the components of a battery that they say could bring about the ultimate miniaturization of energy storage components.
The structure is called a nanopore: a tiny hole in a ceramic sheet that holds electrolyte to carry the electrical charge between nanotube electrodes at either end. The existing device is a test, but the bitsy battery performs well. First author Chanyuan Liu, a Ph.D. student in materials science & engineering, says that it can be fully charged in 12 minutes, and it can be recharged thousands of time.
Billion Holes Can Make a Battery - [Link]