Very common on old equipment, today they seem to have disappeared completely. I am talking about those pushbutton banks of which only one button could be activated at a time, like cassette player’s piano keys or channel selectors on radios. Thanks to a mechanical system pressing one button would release all the others that were pressed (normally only one). Today such tasks are handled by microcontrollers, but this project shows how to do it without. Four relays are switched by four pushbuttons, but only one relay can be on at any time. Add more channels to taste.

One of the “raisons d’être” of the Elektor Labs website is to help people advance with their projects. When posting a project, a special SOS badge can be activated when help from other users is solicited. This SOS project, all the way from New Zealand, is about restoring a lathe to which the poster would like to add a motor controller with self-excited capacitor/DC-injection braking. If you are into electric motors and motor controllers, this might be an interesting read. Maybe you can help with your expertise?

At Elektor Labs we are confronted at all sorts of projects, from simple ideas to fully developed all-singing all-dancing multi-board constructions. Some projects are more useful or practical than others, but they all fill the need of at least the person who posted it. Here is one of those, a microcontroller controlled resistor decade box. According to the designer, it can produce any resistance between 0 ohms and 10 meg. If it goes all the way down to zero is questionable looking at the wiring involved, that it will help you consume your stock of relays, on the other hand, is for sure.

One month ago we asked Elektor Labs users to design an original fading LED circuit and publish its schematic together with a video as a project. The best design will be rewarded with a €100 gift certificate. Many people took up the challenge with fifteen different circuits (some even with variations) as a result, from simple fade-in-fade-out to designs with bells and whistles. Now you can vote for the one you like the most…

-- Hey guys, look what I made. I put a ball bearing in the center of this flat multi-lobed structure so that it can spin along its axis. That’s all it does, it just spins and I am going to sell billions of ‘em. -- Sure you are, dude. Now go away. The rest is history and even at Elektor Labs we encounter fidget spinner projects. This particular project combines the fidget spinner with a persistence of vision (POV) LED display. Will it be ready before the hype is over? Or will it create its own hype? Decide for yourself.

Everybody welcomes a good idea. Here is one for those who construct small circuits on prototyping board and then let them lie around without any form of protection, gathering dust. Such contraptions usually end up dead because wires come loose or components get bend, creating short circuits or bad contacts. There is a simple solution to this problem: put the project in an enclosure. It doesn’t have to be something fancy or expensive; in many cases an old audio cassette case is good enough. Transparent, easy to cut and open, they are perfect for the job. And they can be stacked, allowing your projects to be stored neatly in a drawer or cupboard.

LEDs that slowly fade in and out to indicate stand-by mode or the availability of a new message have been made popular by smartphones and other gadgets. To do this is easy enough with a microcontroller and some programming, but can you do it without? So here is the deal: design an all-analog fading-LED circuit and post it on Elektor Labs. Add a short video to show it off. The best design wins a €100 gift certificate. Deadline: September 24, 2017.

Here is a simple, little circuit that makes loud, useless noises using an ATtiny45 programed in Bascom-AVR. It is a remake of a circuit from 1979, showing that something that required aranging almost two dozen components in an ingenious way 40 years ago can be done today with a 8-pin microcontroller and three lines of code. Included in the project is the original circuit for you to admire and take inspiration from.

LEDs that slowly fade in and out to indicate stand-by mode or the availability of a new message have been made popular by smartphones and other gadgets. To do this is easy enough with a microcontroller and some programming, but can you do it without? So here is the deal: design an all-analog fading LED circuit and post it on Elektor Labs. Add a short video to show it off. The best design wins a €100 gift certificate. Deadline: September 24, 2017.

So you’re back from holidays spent somewhere in a hot and sunny place, enjoying the a hotel or beach resort with organized activities like morning aerobics in the swimming pool and loud parties at night and where you karaokeed your lungs out of your body, and now you are missing that festive ambience? Then it is time to build this great all-analog, all-through-hole microphone amplifier and impress your friends and family once again with your vocal capabilities.