Pure TTL based clock

We’ll just say, [Kenneth] really likes clocks. His most recent is a pure 7400 series TTL based one, ie no microcontroller as seen in the past, here, here, and here. The signal starts out as a typical 32,768 crystal divided down to the necessary 1Hz, which is then divided again appropriately to provide hours and minutes.

As far as TTL clocks go, this is nothing too original; until it comes to his creative button interface. By using a not as sexy as it sounds multivibrator, he can produce a clean square wave instead of the figity signals produced from buttons to advance and set the time. Like always, he also provides us with a thorough breakdown of his clock, after the jump. Continue reading “Pure TTL based clock”

Shadow buttons

This art installation uses buttons made of light. A projector fills up the walls and ceiling of a room while a webcam monitors the pattern for changes. When the luminosity of a given area changes due to a shadow, a midi event is triggered. The software that controls the system is written in C# and uses the Emgu CV library to handle the image processing. In the video after the break you can see that creating shadows with your hands prompts changes in the image as well as the sound.

Continue reading “Shadow buttons”

Push potentiometer from spares


In an effort to simplify his interface, [danwagoner] cobbled together this push potentiometer. It utilizes a potentiometer mounted directly above a push button with a spring mounted around it. This way the user has only one item to deal with. They can twist the knob and press down on it to push the button.  We love seeing people come up with ways of creating their own items instead of buying something. This was fairly inventive and reminds us of the LED buttons we saw back in January. Great job [danwagoner].

LED push buttons


[pros] has come up with a very elegant way of making lighted buttons (translated). Using a bunch of small push buttons harvested from old CD players, he rigged this unique way of mounting LEDs. Each LED has two buttons under it. They are wired in parallel, so if either of them is pushed, the button works. The LED isn’t actually soldered where it passes through the board. The anode and cathode are bent around and soldered to allow the LED a little bit of travel.  There’s a good picture of how he did this on the site. The rest of the details might be hard to decipher though, it looks to be in dutch.

[thanks Tom]

Parts: Tactile switches for your next project

Electronics parts can be a pain to choose. It’s often hard to tell from manufacturers’ datasheets if a part will fit your design. We auditioned six different tactile switches to find a cheap button to use in upcoming projects. A tactile switch, also called a momentary button or push-to-make switch, is commonly used for input and microcontroller resets. This type of button creates a temporary electrical connection when pressed.

Footprints for most of these buttons are available in the Cadsoft Eagle library switch-tac, or in the Sparkfun parts library under TAC_SWITCH. Buttons in the image above are discussed from left to right. Continue reading “Parts: Tactile switches for your next project”

PSP L2/R2 button mod

This is quickly becoming an unintentional “game controller Saturday”. We haven’t been covering the PSP much lately, so this is a treat. AcidMods forum member [Electro] put together a quick guide for adding two missing shoulder buttons to the PSP. The L2 and R2 buttons are used while playing Playstation 1 games and are usually mapped to directions on the joystick. This mod jumps the joystick’s contacts an relocates the buttons to the shoulders. The switches used in the post seem kind of bulky, but you’re free to use anything that fits.

[via Engadget]

Tips on picking the right case

Finding the right enclosure to house your latest project can be tricky, so Sparkfun wrote up some handy tips on the how to pick the right one.

The most important tip is to have your components measured before acquiring a case; even being a few milimeters too small can put you back at square one. To do this right, it’s useful to look at the dimensional drawings of prospective cases to get a sense for the size. These typically include recommended shapes for PCBs too.

You may find a case that meets your dimensional needs but doesn’t have the appropriate mounting bosses. To get the placement right, screw some plastic standoffs to the PCB, then use super glue to attach them firmly to the case.

Tips on button choices, hole drilling, and other typical issues with case modification can also be found in this guide. If this is something that’s been stumping you, give it a look.