This Clock Knock Block has a bit of everything; milling, Arduino, sensing, solenoids, and plenty of dirty puns. Just knock on the box or on the table right next to it and the time of day will be played back to you in a series of crisp, clean knocks. A big part of the fun here is that the box is a musical instrument.

If you take a look inside you’ll find an Arduino, a piezo sensor, a solenoid, and a nine-volt battery. The piezo sensor detects your knocking as an input. It can even listen to and repeat back a series of your knocks. The Arduino actuates the solenoid, which strikes the wooden enclosure, producing the knocking sound.

We’ve embedded a video of this useless machine after the break (that’s where all the puns are). One note for your own build; this box is made out of mahogany and because it is used as a resonance chamber, this may not work as well if it isn’t milled from a piece of quality lumber. Read the rest of this entry »

It’s Independence Day, so if you have pets and planned a trip, chances are you wrangled a pet sitter to keep your pet from starving or dehydrating to death. Next time, consider letting this infinite water dispenser help you instead.

The dispenser is made of a Tupperware tub, a fish tank water filter, a float switch, and a water solenoid valve. It works essentially the same way as any toilet: the solenoid valve lets water into the filter where it is dispensed to the Tupperware container. The float switch is activated when the water in the container reaches a certain level. When the water level drops due to evaporation or thirsty pets, the float switch goes down and triggers the solenoid to let in more water. The whole works are powered by a GFI outlet for safety since this project involved water, electricity and pets.

Another day, another EE that refuses to play Guitar Hero properly. [Julian Bleecker] went into the design of this Guitar Hero actuator not really knowing how to size solenoids properly. Luckily, trial and error can get you a long way. The first solenoids he purchased couldn’t apply enough force. The second was overkill. It was certainly strong enough but too heavy and too large to mount to the neck. The final set ended up being both the right size and working well even at 12V, half the design voltage. The elegant mounting system is what really makes this project shine. [Julian] provides the schematic for the ATmega168 driver board, which is an Arduino stripped of the extraneous bits.

Related: Slashbot and AutoGuitarHero

[via Make]

Today’s episode of BoingBoing TV visits [David Byrne]’s Playing the Building installation which we covered before. The video provides some insight into the artistic process: they wandered around and whacked things with mallets to see what sounded good. They use counterweighted motors to vibrate cast iron girders and columns. Many of the empty radiators are being struck by solenoids. He says the installation is very approachable because people realize that even if a skilled musician sat down they wouldn’t be any better at playing the device.