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]
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]
This project provides some lighting effect by the blinking pattern of the bulbs connected at its output. Up to 8 Bulbs can be connected in between connector CN2 to CN9 and AC power to control them should be connected at Connector CN10. DC Power should be applied at Connector CN11 in accordance with the polarity marked on this connector. Care should be taken while using this it as it contains Main Power on the board.
Microcontroller based running light controller - [Link]
This project is an one Channel Relay Driver suitable for a variety of projects. Check specifications on the page below.
One Channel Relay Driver - [Link]
Low-cost, high quality reflow oven for surface-mount PCB assembly at home. Get professional results consistently and reliably!
ControLeo2 Reflow Oven - [Link]
by Anthony Smith @ edn.com:
The simple current-limiting load switch shown in Figure 1 will be familiar to most readers. In this circuit, a high level signal applied to the input switches on MOSFET Q2, which energizes the load. The load current is limited by negative feedback applied via Q1.
Load switch with self-resetting circuit breaker - [Link]
Before I began the installation of my Yaesu FT-8800 in my car I knew I wanted automatic power ON / OFF. This is a feature that I have always felt was lacking in my other mobile rigs as I am forever leaving my ham radio on long after I have departed the car.
Let’s start with an action packed video of the finished product, then we can talk about how we got there.
Mobile Radio Power Controller ( MRPC ) - [Link]
A Flexible Oven Controller controlled via touch screen or through USB. Draw and download your own profiles using free Profile Creator.
Zallus Oven Controller - [Link]
The Arduino and Cloud-based homebrewing controller by Martin Kennedy of TheBedroomLaboratory:
It’s just a basic site, based on this Scotch.io tutorial, which is currently plotting the temperature in my sitting room. It’s got a PHP backend (Laravel framework with RESTful API), MySQL database and an AngularJS frontend with (n3-chart/d3 for the graph). In the house, I’ve whacked together a quick breadboard circuit which comprises of an Arduino clone, a DS18B20 Temperature Sensor (with resistor for the i2c connection) and an ESP8266 module. Every minute, this wireless sensor POSTs the temperature to our REST API. This value is saved in the database and will appear in the graph whenever the page is opened. To hook it up to a fermenter, the sensor would just be placed in a thermowell in the fermenter bucket so we can see the beer temperature over time.
Brewmonitor: The Arduino-powered, cloud-based homebrewing controller - [Link]
Remote control your electrical devices through your local network or internet. The circuit contains one output (Relay) and one input (isolated input). The whole project was built by using arduino nano platform and an ENC28J60 ethernet module. It can be used the W5100 ethernet module instead of ENC28J60, by replacing the UIPEthernet library to Ethernet library.
Moreover, the control is made from the Android application I wrote and it’s available on Google Play (https://play.google.com/store/apps/details?id=com.serasidis.NetworkRelay).
The schematic diagram, arduino sketch, photos and demonstration video is on my web site:
Arduino Network relay - [Link]