So you need to hear the secrets that are being spilled in the building across the street? If the conversation is happening over the phone you could build a DIY Telephone Listening Bug and tune into the conversation on a radio but what if the conversation is  happening between two people in the room? The answer is a Laser Listening Device, we have featured one of these DIY Laser Listening Devices in the past but this project article by Lucid Science is laid out and explained better.

The idea is that sound from someone speaking will vibrate the window that is in the same room as them. If you bounce a laser beam from a 5mW laser module off the window the laser beam will be deflected slightly as the window vibrates. If you monitor this vibration  you will be able to hear what is being said.

Via: HG Comments

Sacha De’Angeli from ChemHacker has released the schematics and source code of the Scanning Tunneling Electron Microscope. The STM is Arduino based and has been a build in progress for quite a long time now. Looks like it is at a great state now! See the Wikipedia page for more generic information about Scanning Tunneling Electron Microscopes.

“The STM is based on the concept of quantum tunneling. When a conducting tip is brought very near to the surface to be examined, a bias (voltage difference) applied between the two can allow electrons to tunnel through the vacuum between them. The resulting tunneling current is a function of tip position, applied voltage, and the local density of states (LDOS) of the sample.^[4] Information is acquired by monitoring the current as the tip’s position scans across the surface, and is usually displayed in image form. STM can be a challenging technique, as it requires extremely clean and stable surfaces, sharp tips, excellent vibration control, and sophisticated electronics.“

Who says that cool things can’t be made using bubble gum and Popsicle sticks. This PIC Microcontroller Based Writing Robot is much more than a collection of gears, drinking straws and string, watch the video as David who built the robot is able to make the robot draw with a pen.

If you are thinking about Halloween already have a look at the Remote Control Halloween Skeleton Riding a Skateboard that Rodger Cleye put together. If the Skeleton isn’t scary enough have a look at the model that he stuck onto the board. Not sure which one would scare the kids more?

Have a look at this crazy University of Pennsylvania Quadrotor, just think about the issues getting stable flight not to mention the flight recovery this Quadrotor is capable of.

Via: Make and Engadget

Jason sent in his latest creation, it’s a  1.25kJ Coilgun. Check out the cool video of it below, you will get a good overview of how it works and see it in action. I like the fact that he is re-using some parts in the build like the cell phone charger for some of the low voltage circuit needs. By the looks of the damage caused by the gun I am thinking that this might be the most powerful one we have seen yet. I like the dial that allows the max charge voltage to be dialed in so that the system can’t overcharge. Pulling the trigger disconnects the charge circuit and triggers the SCR which dumps the capacitor energy into the coil.

If you like coil guns make sure you have a look at some of the others we have featured in the past.

“Some technical data:

- Action: single stage, bolt
– Power supply: 12V NiMH battery (fires about 15 times/charge)
– Charging: 40 watt regulated ZVS flyback driver (charge time ~30s)
– Capacitor bank: 4x 3900uF @ 400VDC
– Stored electrical energy: ~1.25kJ
– Switch: SCR
– Efficiency: unknown, probably 1-3%
– Body: lightweight ABS plastic pipe and sheets”

Instructables member drj113 has put together a powerful Networked DIY Watering Controller. It has a AtMega168 at its heart and uses a RTC to keep accurate track of time. Where I live there is no restrictions on lawn watering but this is a good flexible system that can save you costly fines if your area imposes lawn watering restrictions.

“The sprinkler controller is built on the base of my Adruino Ethernet controller.  The Arduino ethernet controller provided a basic network connected ATMega328 chip, and had a number of spare I/O lines. I extended the PCB design to provide 6 solid state outputs, each able to drive +12v at 300mA, which is enough for a watering solenoid. Each solenoid output is driven from a NPN transistor, as shown by the attached picture.  To turn on the transistor, the port pin is simply driven high.  I decided to use individual transistors, as they cost $0.03 each, and if they are destroyed, they are individually replaceable easily.”