Adding A Backlight To A Cheap Multimeter

We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.

After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.

The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.

[via Reddit]

On Your Phone While Driving an Electric Skateboard

Skateboards are fun, but you have to do all that pesky kicking in order to get anywhere. That’s why [Nick] decided to build his own electric skateboard. Not only is the skateboard powered with an electric motor, but the whole thing can be controlled from a smart phone.

[Nick] started out with a long board deck that he had made years ago. After cleaning it up and re-finishing it, the board was ready for some wheels. [Nick] used a kit he found online that came with the trucks, wheels, and a belt. The trucks have a motor mount welded in place already. [Nick] used a Turnigy SK3 192KV electric motor to drive the wheels. He also used a Turnigy electronic speed controller to make sure he could vary the speed of the board while riding.

Next [Nick] needed some interface between a smart phone and the motor controller. He chose to use an Arduino Nano hooked up to a Bluetooth module. The Nano was able to directly drive the motor controller, and the Bluetooth module made it easy to sync up to a mobile phone. The Android app was written using MIT’s App Inventor software. It allows for basic control over the motor speed so you can cruise in style. Check out the video below for a slide show and some demonstration clips.

It’s a popular project, and eerily similar to the one we saw a couple months back.

Continue reading “On Your Phone While Driving an Electric Skateboard”

Hard Drive Rootkit Is Frighteningly Persistent

There are a lot of malware programs in the wild today, but luckily we have methods of detecting and removing them. Antivirus is an old standby, and if that fails you can always just reformat the hard drive and wipe it clean. That is unless the malware installs itself in your hard drive firmware. [MalwareTech] has written his own frightening proof of concept malware that does exactly this.

The core firmware rootkit needs to be very small in order to fit in the limited memory space on the hard drive’s memory chips. It’s only a few KB in size, but that doesn’t stop it from packing a punch. The rootkit can intercept any IO to and from the disk or the disk’s firmware. It uses this to its advantage by modifying data being sent back to the host computer. When the computer requests data from a sector on the disk, that data is first loaded into the disk’s cache. The firmware can modify the data sitting in the cache before notifying the host computer that the data is ready. This allows the firmware to trick the host system into executing arbitrary code.

[MalwareTech] uses this ability to load his own custom Windows XP bootkit called TinyXPB. All of this software is small enough to fit on the hard drive’s firmware. This means that traditional antivirus cannot detect its presence. If the owner of the system does get suspicious and completely reformats the hard drive, the malware will remain unharmed. The owner cannot even re-flash the firmware using traditional methods since the rootkit can detect this and save itself. The only way to properly re-flash the firmware would be to use an SPI programmer, which would be too technical for most users.

There are many more features and details to this project. If you are interested in malware, the PDF presentation is certainly worth a read. It goes much more in-depth into how the malware actually works and includes more details about how [MalwareTech] was able to actually reverse engineer the original firmware. If you’re worried about this malicious firmware getting out into the wild, [MalwareTech] assures us that he does not intend to release the actual code to the public.

LED Sign Brightens Up The Beach After Dark

[Warrior_Rocker’s] family bought a fancy new sign for their beach house. The sign has the word “BEACH” spelled vertically. It originally came with blue LEDs to light up each letter. The problem was that the LEDs had a narrow beam that would blind people on the other side of the room. Also, there was no way to change the color of the LEDs, which would increase the fun factor. That’s why [Warrior] decided to upgrade the sign with multi-colored LEDs.

After removing the cardboard backing of the sign, [Warrior] removed the original LEDs by gently tapping on a stick with a hammer. He decided to use WS2811 LED pixels to replace the original LEDs. These pixel modules support multiple colors and are individually addressable. This would allow for a wide variety of colors and animations. The pixels came covered in a weatherproof resin material. [Warrior] baked the resin with a heat gun until it became brittle. He was then able to remove it entirely using some pliers and a utility knife. Finally, the pixels were held in place with some hot glue.

Rather then build a remote control from scratch, [Warrior] found a compatible RF remote under ten dollars. The LED controller was removed from its housing and soldered to the string of LEDs. It was then hot glued to a piece of cardboard and placed into the sign’s original battery compartment. Check out the video below for a demonstration. Continue reading “LED Sign Brightens Up The Beach After Dark”

Smile for the Raspberry Pi Powered Photo Booth

[Roo] was tasked with finding a better way to take corporate employee photos. The standard method was for a human resources employee to use a point and shoot camera to take a photo of the new recruits. The problem with this method is many people feel awkward trying to force a smile in front of other people. Plus, if the photo turns out poorly many people won’t ask to have it retaken so as not to feel vain or inconvenience the photographer. [Roo’s] Raspberry Pi powered photo booth solves this problem in a novel way.

The new system has the employee use their own mobile phone to connect to a website running on the Pi. When the employee tells the Pi to snap a photo, the system uses the Raspberry Pi camera module to capture an image. [Roo] actually 3D printed a custom adapter allowing him to replace the standard camera lens if desired. The photo can be displayed on an LCD screen so the user can re-take the photo if they wish.

The system is built into a custom case made from both 3D printed and laser cut parts. The front plate is a frosted white color. [Roo] placed bright white lights behind the front panel in order to act as a flash. The frosted plastic diffuses the light just enough to provide a soft white light for each photo taken. Once the photo is selected, it can then be uploaded to the company database for use with emails, badges, or whatever else.

[Roo] also mentions that the system can easily be changed to send photos via Twitter or other web applications. With that in mind, this system could be a great addition to any hackerspace or event. The code for an older version of the project can be found on the project’s github page.

Continue reading “Smile for the Raspberry Pi Powered Photo Booth”

Flat Pack Elastic Band Lamp is a Thing of Beauty

[Matt] was looking for a project for his senior industrial design studio at Wentworth Institute of Technology. He ended up designing a clever lamp that can be flat packed. [Matt] started by drawing out designs on paper. He really liked the idea of combining curves with straight lines, but he wanted to translate his two-dimensional drawings into a three-dimensional shape.

zOz0ys6 - ImgurHaving access to a laser cutter made the job much easier than it could have been and allowed [Matt] to go through many designs for the lamp frame. The two main pieces were cut from acrylic and include mounting pegs for the elastic bands. The two plastic pieces are designed to slot together, forming a sort of diamond shape.

The final version of the lamp required that the elastic bands had holes punched in them for mounting. The holes were placed over the small pegs to keep the bands in place. [Matt] used 3/4″ industrial elastic bands for this project. He then used a 120V 15W candelabra light bulb to illuminate the lamp. The final design is not only beautiful, but it can be flat packed and manufactured inexpensively.

If you want more inspiration for artistically designed lamps check out this one that uses the corrugation in cardboards as a shade pattern.

[via reddit]

Smarter-than-wood Saw Blade Makes Perfect Foldable Joints

[Andrew Klein] knows the pain of building drawers from plywood. It can be a pain to get all of the pieces measured and cut just right. Then you have to line them up, glue them together, and clamp them perfectly. It’s time-consuming and frustrating. Then one day it hit him that he might be able to make the whole process much easier using a custom saw blade.

The the video below, [Andrew] does a great job explaining how the concept works using a piece of paper. The trick is that the plywood must be cut in a very specific shape. This shape results in the plywood just barely being held together, almost as if it’s hinged. The resulting groove can then be filled with wood glue, and the plywood is folded over on itself. This folding process leaves no gaps in the wood and results in a strong joint. Luckily this special shape can be cut with a specialized saw blade.

This new process removes the requirement of having five separate pieces for a drawer. Instead, only four cuts are needed on a single piece of square plywood. The corners are then removed with a razor blade and all four sides are folded up and into place. [Andrew] shows that his prototype blade needs a little bit of work, but he’s so hopeful that this new invention will be useful to others. Continue reading “Smarter-than-wood Saw Blade Makes Perfect Foldable Joints”