Piezoelectric elements can be used to make sound or detect sound. Steve Hoefer has made a Knock Lock, which is a device that can listen to knocks on the door. If the sequence of knocks is the same as the recorded knock sequence it unlocks the deadbolt on the door. Steve was the guy who also made the Dice Reading Machine.

Via: Zedomax

"While working on another project I ran across the Arduino knock sensor tutorial. Sensing a single knock is a great little project for learning about microcontrollers, but what about sensing specific knocks? Seeeeecret knocks? And if we could detect a secret knock, shouldn’t it unlock a door? If you can’t tell by looking this was cobbled together from spare stuff around the lab, it’s not much more than a piezo speaker, a tiny gear reduction motor, and an Arduino. And PVC pipe."

Not exactly the most common boat you will see at your local boat launch. The SCUBACRAFT Personal Submarine will be available in 2010. There is an interview over at James List that you may be interested in if you have some extra cash burning a hole in your pocket.

"The modular configuration allows for the electric system to be removed and replaced as necessary, adding extra batteries for extended operations or more thrusters for more power. A wide range of accessories including lights and cameras can be added to extend its underwater capability and enhance the user’s experience. Scubacraft uses a high powered jet propulsion system that will easily tow a water-skier and inflatable water toys. The trimaran hull configuration gives inherent stability as a diving platform and with its air entrapment design, results in high speeds on a cushion of air."

AnotherCoilGun has been hard at work making his LED control board even smaller! His other tiny version looks huge in comparison.

Mitch Schoch from SimpleVoice.com built an interesting 4 axis DIY Foam Cutting CNC Machine. It has lots of control since all 4 motors can be driven independently. His design is modular, he has used phone jacks and 24 gauge phone cable to provide power the motors. Everything was purchased from the local hardware store so there are no exotic parts in the unit. From the video he looks to be using standard threaded rod and some big drawer slides to provide smooth motion with the use of the stepper motors.

Dave Jones from the EEVblog did a review of the PICkit 3 Programmer/Debugger. Watch the video above but to sum it up he was not impressed with the new version. The video below is a video that Microchip made in response to Dave’s video review. Lets just say that I am VERY impressed by Microchip putting together this great video poking fun at themselves and on such short notice. Well done Microchip!