by Dan Meeks @ edn.com:
This Design Idea is a solid state relay (SSR) which uses a triac to switch AC loads at high current. There are plenty of simple SSR circuits available, but this may be the simplest circuit that achieves turn-on and turn-off only when the AC line voltage is near zero.
Simple SSR has zero-cross on/off switching - [Link]
by Martin @ harizanov.com:
The WiFi SSR board project changed a bit and I use classical relays instead of SSRs now. The reason is that SSRs tend to get quite hot when switching larger loads, and the 8A relays I last used actually could be used for max 2.5A load switching with no heat sink. The high quality relays I now use allow 10A load switching and are rather quiet. I also changed the design a bit so that it would fit in a box (DIN rail compatible) for increased safety.
WiFi Thermostat with weekly scheduler - [Link]
by CsabaP @ instructables.com:
This Instructable shows you how to build a clap activated LED strip. The whole project is based on the Adafruit’s Secret Knock Activated Drawer Lock, where the user can record a secret knock pattern which will open the lock inside the drawer. I thought that I could use this to siwtch an LED strip on and off with a handclap pattern. So let’s begin!
Clap activated LED strip - [Link]
This evaluation board has been developed for ROHM’s H-Bridge driver customers evaluating the BD62x2FP series. The BD62x2FP series can operate across a wide range of power supply voltages (from 3V to 32V max), supporting output currents of up to 2A. PWM signal control (20 kHz-100 kHz) or VREF control modes are used to vary motor rotation speeds. ROHM’s ICs are complete with over current protection (OCP), over voltage protection (OVP), thermal shutdown (TSD) and under voltage lock-out (UVLO) protection circuits while also facilitating a low-power consumption design (10μA max).
Rohm H-Bridge Evaluation Board - [Link]
by Tim @ timleland.com:
Have you ever wanted to wirelessly control power outlets from your phone? You could buy a Belkin WeMo Switch for over $40 for 1 outlet or build your own with 5 outlets for under $35 if you already own a Raspberry Pi. Hopefully this post will guide you in the right direction.
Wireless Power Outlets RF from Raspberry Pi - [Link]
Chris Holden of Nerd Club has build a temperature controller with a simple menu system:
After what seems to have been a very long time, it was nice to poke more wires into a breadboard and make something actually useful for a while! Here’s a simple temperature monitor for our injection moulding heater block. It uses three buttons for setting the parameters and some pretty dodgy-looking routines to detect “short” and “long” presses.
Temperature controller for K-type thermistor and MAX6675 - [Link]
by alistair_uk @ instructables.com:
This is a very low cost and basic from of home automation allowing you to turn on and off lights and other devices using your computer or mobile phone.
It has been built and tested use using UK power plugs, but the same protocol is used on many budget remote power switchers from around the world.
Internet Controlled Mains Switcher - [Link]
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]