Fingerling Disemboweled For Your Entertainment

December 28, 2017 by Tom Nardi 21 Comments

Due to the graphic nature of this post, small children and the elderly may want to leave the room. One of the hottest toys this holiday season has been gutted like a fish so that we may better understand the nature of its existence. Or maybe just what kind of sensors and motors the craftsmen over at WowWee managed to cram into a “robot” with an MSRP of only $15 USD.

[Josh Levine] mercilessly tears a Fingerling Monkey limb from limb on his blog, and points out some interesting design decisions made. While some elements of the toy are rather clever, there’s a few head-scratchers to be had inside the Fingerling. It’s interesting to see the final results of a decision process that had to balance the relatively rough life such a toy will live with the ever crucial cost of production.

The eyelids are particularly well thought out, operated by charging a coil under a magnet which is embedded in the plastic. Opening and closing the eyelids without a separate motor or gearbox is not only easier and cheaper, but prevents the possibility of damage if a child attempts to force open the eyes or otherwise manipulate the mechanism.

Other cost saving measures include the use of foil tape as a capacitive sensor, and simple ball-filled tilt sensors to detect orientation rather than an expensive accelerometer.

Interestingly, other parts of the toy seem overengineered in comparison. A cam and limit switch are used to detect when the Fingerling’s head has turned to its maximum angle, when it would have been cheaper and easier to simply detect motor stall current.

If you’re interested in seeing what makes popular toys tick, we’ve got a number of plaything tear downs which are sure to keep you satiated until the next big holiday toy rolls around.

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Resurrecting Dead LED Lightbulbs

December 19, 2017 by Tom Nardi 29 Comments

If you’ve gone down the lighting isle of a store recently, you’ve no doubt noticed we are firmly in the age of the LED light bulb. Incandescent bulbs are kept in small stock for those who still have the odd-ball use case, there’s usually a handful of CFL bulbs for those who don’t mind filling their house with explosive vials of hot mercury, but mostly its all LED now. Which is as it should be: LED lighting is clearly the superior choice in terms of energy efficiency, lifetime, and environmental impact.

Unfortunately, a lot of the LED bulbs you’ll see on the rack are of pretty poor quality. In an effort to drive cost down corners get cut, and bulbs which should run for decades end up blowing after a couple of months. After yet another one failed on him, [Kerry Wong] decided to do a teardown to examine the failure in detail.

He notes that most of the LEDs seem to fail in the same way, flickering after they are switched on until they just stop lighting up entirely. This hints at an overheating issue, and [Kerry] opines that aesthetic and cost considerations have pushed heat dissipation to the back burner in terms of design. It also doesn’t help that many of these bulbs are sitting in insulated recessed fixtures in the ceiling, making it even harder to keep them cool.

Once he separates the actual LEDs from the driver circuitry, he is able to determine that the emitters themselves still work fine. Rather than toss the whole thing in the trash, it’s possible to reuse the LEDs with a new power source, which is quickly demonstrated by showing off a shop light he built from “dead” LED light bulbs.

[Kerry Wong] isn’t the only one to put his LED bulbs under the knife. We’ve covered a number of teardowns which explore the cutting edge of home lighting; for better or for worse.

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A Teardown Of Something You Should Not Own

December 1, 2017 by Brian Benchoff 67 Comments

GPS jammers are easily available on the Internet. No, we’re not linking to them. Nevertheless, GPS jammers are frequently used by truck drivers and other people with a company car that don’t want their employer tracking their every movement. Do these devices work? Are they worth the $25 it costs to buy one? That’s what [phasenoise] wanted to find out.

These tiny little self-contained boxes spew RF at around 1575.42 MHz, the same frequency used by GPS satellites in high Earth orbit. Those signals coming from GPS satellites are very, very weak, and it’s relatively easy to overpower them with noise. That’s pretty much the block diagram for these cheap GPS jammers — put some noise on the right frequency, and your phone or your boss’s GPS tracker simply won’t function. Note that this is a very low-tech attack; far more sophisticated GPS jamming and spoofing techniques can theoretically land a drone safely.

[phasenoise]’s teardown of the GPS jammer he found on unmentionable websites shows the device is incredibly simple. There are a few 555s in there creating low-frequency noise. This feeds a VCO with a range of between 1466-1590 MHz. The output of the VCO is then sent to a big ‘ol RF transistor for amplification and out through a quarter wave antenna. It may be RF wizardry, but this is a very simple circuit.

The output of this circuit was measured, and to the surprise of many, there were no spurious emissions or harmonics — this jammer will not disable your cellphone or your WiFi, only your GPS. The range of this device is estimated at 15-30 meters in the open, which is good enough if you’re a trucker. In the canyons of skyscrapers, this range could extend to hundreds of meters.

It should be said again that you should not buy or use a GPS jammer. Just don’t do it. If you need to build one, though, they’re pretty easy to design as [phasenoise]’s teardown demonstrates.

Glue Gun Teardown Reveals Microcontroller Mystery

November 23, 2017 by John Baichtal 64 Comments

[electrobob] got a Bosch GluePen cordless hot glue gun. The thing has some nice features — it heats up in fifteen seconds, and charges via USB, and is generally handy for those small and quick jobs that hot glue guns were made to perform. At first glance it seems like a huge improvement over the plug-in varieties, which seem to take forever to heat up when all you need is a quick dab of glue.

As cool as the product sounded, [bob] did what any right-minded hacker would do and opened it up to see how that sucker work and found an ATtiny24A inside. What’s most interesting is that there appears to be no temperature regulation or sensing capability, with the exception of the thermistor in the battery-charging circuit. It’s an intriguing mystery.

The ATtiny controls a power MOSFET that brings the heating element to “approximately 170 degrees” according to the manual. [bob] could find no temperature regulation of the hot end, which measures a steady 12 V at the gate of the transistor then entire time the glue gun is powered on.

That ATtiny24A that runs the whole thing packs 12 GPIO pins, 4 PWM channels, and 2 KB program memory. It appears a bit overpowered for a glue gun controller. [bob] found one of the Tiny’s pins connected the heating element and another to the charging circuit. Maybe a shutoff in case the battery catches fire?

Without a clear shot of the back of the board, it’s a bit of a guessing game, but eight of the twelve GPIO pins appear to be in use. Leave your theories in comments. And if you’ve got any bright ideas about what to do with the remaining four GPIO pins, have at it!

For another of [bob]’s tool hacks, check out his constant current sink we posted earlier this year.

Teardown Of A Cheap Glue Gun

November 22, 2017 by Jenny List 25 Comments

A hot glue gun is one of those standard tools of the hardware hacker’s bench, called upon to provide adhesion between an astonishing range of materials, and to provide a handy filler and strain relief in the form of blobs of polymer glue. We’ve all got one, but how many of us have taken a look inside it?

[Andrew Lorimer] bought a super-cheap eBay glue gun, and subjected it to a teardown. As you might expect, he found it to be a pretty simple device with only a trigger mechanism and a dumb heating element, but his write-up is of passing interest because he’s characterised its heating element. It has a positive temperature coefficient, which means that its resistance increases from around 2.5 kΩ at room temperature to about 7 kΩ at its 150 ºC operating temperature. This limits the current, and provides a very simple thermostat action.

The build quality is surprisingly good for such a cheap appliance, and he notes a surfeit of screws holding its shell together. But the quality of the insulation and strain relief leaves a lot to be desired, and he wonders whether it truly qualifies for its double-insulated logo. The LED pilot light is simply fed from the 240 V mains supply through a 250 kΩ resistor which he replaces with a 12 kΩ component for a brighter result.

We cover plenty of teardowns here at Hackaday. Often they are of extremely expensive and complex devices, but sometimes they are of much simpler subjects.

Mike Harrison’s Reverse Engineering Workshop

October 31, 2017 by Mike Szczys 11 Comments

Hardware teardowns are awesome when guided by experts. One of our favorites over the years has been [Mike Harrison], who has conquered teardowns of some incredibly rare and exquisitely engineered gear, sharing the adventure on his YouTube channel: mikeselectricstuff. Now he’s putting on a workshop to walk through some of the techniques he uses when looking at equipment for the first time.

[Mike] will be in Pasadena a few days early for the Hackaday Superconference and floated the idea of hosting a workshop. We ordered up some interesting gear which he hasn’t had a chance to look at yet. A dozen lucky workshop attendees will walk through the process [Mike] uses to explore the manufacturing and design choices — skills that will translate to examining any piece of unknown gear. He may even delve into the functionality of the equipment if time allows. Get your ticket right now!

To keep things interesting we’re not going to reveal the equipment until after the fact. But follow the event page where we’ll publish the details of his reverse engineering work after the workshop.

[Mike] is the badge designer for this year’s Hackaday Superconference badge. Unfortunately Supercon is completely sold out (we tried to warn you) but you can check out the badge details he already published. And we will be live streaming the Supercon this year — more details on that next week!

Horizontal Magnetic Levitation Experiments

August 21, 2017 by Inderpreet Singh 7 Comments

Levitating chairs from the Jetsons still have a few years of becoming a commercial product though they are fun to think about. One such curious inventor, [Conor Patrick], took a deep dive into the world of maglev and came up with a plan to create a clock with levitating hands. He shares the first part of his journey to horizontal levitational control.

[Conor Patrick] bought an off-the-shelf levitation product that was capable of horizontal levitation. Upon dissecting it he found a large magnet, four electromagnet coils, and a hall effect sensor. These parts collectively form a closed-loop control to hold an object at a specific distance. He soon discovered that in fact, there were just two coils energized by H-bridges. His first attempt at replicating the circuit, he employed a breadboard which worked fine for a single axis model. Unfortunately, it did not work as expected with multiple coils.

After a few iteration and experiments with the PID control loop, he was able to remove unwanted sensor feedback as well as overshoot in control current. He finally moved to a Teensy with a digital PD loop. The system works, but only marginally. [Conor Patrick] is seeking help from the control loop experts out there and that is the essence of the OSHW world. The best part of this project is that it is a journey that involves solving one problem at a time. We hope to see some unique results in the future.

We have covered Acoustic Levitation in the past and the Levitating Clock on a similar beat. We’re certain a more refined approach is on the horizon since many of us are now looking at making one to experiment with on our workbench.