Exposing some fake electronics with too-good-to-be-true prices

[Giorgos Lazaridis] needed an AC adaptor for his Canon PowerShot camera. He hit eBay and was excited to find this branded adaptor for just five bucks! It works and, even though it would sometimes reboot his camera if the cord was twisted around in the jack, he was satisfied that it did what it was supposed to.

That is, until one day he observed some very peculiar behavior while taking pictures of a PIC circuit he was prototyping. When holding the camera and putting his other hand near the breadboard one of the status LEDs in his circuit began flashing sporadically. If he was using the camera with batteries instead of the adapter this didn’t happen.

His first instinct was to hook up the adapter to his oscilloscope and see what is happening on the power bus. The signal is incredibly noisy. Shockingly so. [Giorgos] cracked open the case to see what is going on with the power supply circuit inside. You simply must view the video after the break to see the horror-show he found. The board is poorly soldered, components are not properly seated in their footprints, and our favorite is when [Giorgos] points out a squiggly trace which takes the place of the smoothing inductors.

Have you documented your own fake electronic hardware finds? We’d love to hear about them. [Read more...]

Line-follower is an homage to [Homer]; plans to infringe copyrights

The Chief Knock-a-Homer robot is [Psycho Freaky's] shout out to The Simpsons. The robot design appeared in an episode where [Homer] built [Bart] a fighting robot. Since he’s not robot builder, [Homer] actually climbed inside the shell and dished out sweet vengeance while suffering some severe injuries at the same time.

But [Psycho] has the skills necessary to make this autonomous and keep it looking just like the TV show at the same time. He has a friend with a CNC mill, and used it to cut out case parts from Masonite which were assembled with hot glue. A pair of small servos drive two wheels at the rear of the base, with a ball-bearing universal wheel centered in the front. There are also two downward-pointing sensors which lend it the ability to follow a line as seen in the video after the break.

We love the paint job, it really polishes the look. But [Pyscho] isn’t quite done yet. He plans to add an audio circuit that will give the robot the ability to play back classic sound clips.

[Read more...]

Over-engineering a two-zone thermometer

We love the extra touches that [Andrianakis Haris] added to his two-zone electronic thermometer. It includes features that you just wouldn’t find on a mass-market commercial product because of issues like added cost. For example, you can see that the PCB juts up above the LCD display, allowing the module to be mounted on a pair of screws thanks to the keyhole shape that was drilled in the substrate. I increases the board size greatly, but on a small hobby run this won’t usually affect the price of the board depending on the fab house pricing model.

The design uses an ATmega8 microcontroller to monitor sensors in two different places. There is an onboard LM35 temperature sensor for monitoring the space where the unit resides. A remote sensor module uses a DHT-11 chip to gather data about temperature and humidity. That sensor is wired, but there is one wireless option for the device. Data can be pulled down from it via an optional Bluetooth module which can be soldered to a footprint on the back of the board.

Check out the video after the break to see temperature readings pulled down wirelessly. [Read more...]

Power protection circuit tutorial

Building your first circuit is empowering, but make sure it’s not too empowering. [Jon] sent in a great tutorial of power protection circuits to make sure you don’t release the mystical blue smoke that make electronics work.

There’s an in-depth tutorial of the classic series diode that’s the simplest of all power protection circuits. There’s not much to it – just a diode that provides reverse polarity protection. A fuse and parallel diode doesn’t have the voltage drop a series diode has, but doesn’t do anything for an overvoltage. A P-channel MOSFET gets around the problem of voltage drop, and [Jon] gives us some really nice empirical data to demonstrate his testing setup.

There’s a ton of nice write ups on [Jon]‘s site that are perfect for getting ideas for projects like ten switches on one pin and some strange stuff [Jon] picked up at his Goodwill. If you’ve got any tutorials on general electronics, be sure to send them in on our tip line.

Backplane and mainboard for a 6502 computer

[Quinn Dunki] has been busy through the holidays giving her 6502 processor-based computer a place to live. The most recent part of the project (which she calls Veronica) involved designing and etching a mainboard for the device. In the picture above it’s the vertical board which is right at home in the backplane [Quinn] also designed.

The project is really gaining momentum now. You may remember that it started off as a rather motley arrangement of what we’d guess is every breadboard she owns. From there some nifty hex switches gave [Quinn] a way to program the data bus on the device. Many would have stopped with these successes, but the continuation of the project makes the hardware robust enough to be around for a while. The single-sided boards are playing nicely together, and the next step is to redesign the ROM emulator to use chips for storage. [Quinn] alludes to a side project in which she plans to build her own EEPROM programmer to help with getting code into the experimental computer.

Easy camera tracking with a quadrocopter

[DJ Sures] has been pulling all-nighters lately to get his AR Drone Parrot build off the ground. Now that it’s up and flying around, he managed to get it to follow objects around the room using on board cameras.

For the build, [DJ Sures] used the AR Drone ‘flying video game’ quadrocopter. This toy has two on board cameras that can viewed over wifi. All that’s needed is some interesting software to make things fun. The camera tracking of EZ-Builder software was brought into the mix so the AR Drone can be controlled via object or speech recognition, wiimotes, tablets, or terminals.

[DJ Sures] has come up with some slightly terrifying awesome builds like a Bluetooth Teddy Ruxpin, realistic Wall-E, and an awesome Omnibot 2000 refurb. This is his first flying hack, and the first to fully exploit the camera tracking of the EZ-Builder software. Check out [Sures]‘ copter following him around a room after the break.

[Read more...]

Securing your Keurig with RFID


[Andrew Robinson] and his co-workers are lucky enough to have a Keurig coffee maker in their office, though they have a hard time keeping track of who owes what to the community coffee fund. Since K-Cups are more expensive than bulk coffee, [Andrew] decided that they needed a better way to log everyone’s drinking habits in order to know who needs to cough up the most cash at the end of the month.

He started by tearing down the Keurig B40, making note of the various PCBs inside while identifying the best way to go about hacking the device. The coffee maker is controlled by a PIC, and rather than try to re-engineer things from the bottom up, he left the core of the machine intact and focused on the control panel instead.

He disconnected all of the unit’s buttons from the control board, routing them through an Arduino before reconnecting them to the machine. This essentially rendered the machine inoperable unless triggered by the Arduino, giving [Andrew] control over the brewing process. He wired in an RFID reader from SparkFun, then got busy coding his security/inventory system. Now, when someone wants coffee, they merely need to swipe their office access card over the machine, which enables the use of its control panel.

As you can see in the video below the system seems to work well. If we were to offer some constructive criticism, we would suggest ditching the laptop and rolling the RFID reading/verification into the Arduino instead – other than that, we think it’s great.

[Read more...]