What’s inside a lightning arrestor?

What is inside one of those things? The folks over at Northstreetlabs have set out to answer just that question. You’ve seen these things before, and if you’re uneducated on the subject like myself, you just assumed they were there to stop a possible connection from a power line to the pole/building to which it is attached. Apparently that is part of their purpose. When presented with lightning, however, they turn to conductors allowing the lightning to pass to ground.

You can see their teardown in video form, as well as an explanation of how exactly they work on their site.

iPhone charger teardown shows astounding miniaturization.

There’s no question that Apple has their industrial design down pat; comparing a cell phone charger made by Blackberry or Motorola to the tiny 1-inch-cube Apple charger just underscores this fact. [Ken Shirriff] posted a great teardown of the Apple iPhone charger that goes through the hardware that makes this charger so impressive.

Like most cell phone chargers and power supplies these days, Apple’s charger is a switching power supply giving it a much better efficiency than a simple ‘transformer, rectifier, regulator’ linear power supply. Inside the charger, mains power is converted to DC, chopped up by a control IC, fed into a flyback transformer and converted into AC, and finally changed back into DC, and finally filtered and sent out through a USB port.

The quality of the charger is apparent; there’s really no way this small 1-inch cube could be made any smaller. In fact, if it weren’t for the microscopic 0402 SMD components, it’s doubtful this charger could be made at all.

Comparing the $30 iPhone charger of a cheap (and fake) iPhone charger, the budget charger still uses a flyback transformer but there are serious compromises of the safety and quality. The fake charger doesn’t use a power supply controller IC and replaces the four bridge diodes for a single diode to rectify the AC; a very efficient cost-cutting measure, but it does lead to a noisier power supply.

There’s also the issue of safety; on the Apple charger, there is a (relatively) huge physical separation of  ~340 VDC and your phone. With the off-brand charger, these circuits are separated by less than a millimeter – not very safe, and certainly wouldn’t be UL approved.

It’s worth pointing out that [Ken] compares a similar $7 Samsung charger favorably to the $30 Apple charger. Both are functionally identical, but Apple also has their  marketing down pat, to say the least.

Tip ‘o the hat to [George] for sending this in.

EDIT: In case a 1-inch cube wasn’t impressive enough, check out the euro version of the iPhone/iPad charger. It supplies 1A @ 5V, and isn’t much thicker than the USB port itself. Thanks [Andreas] for bringing this to our attention. If anyone wants to do a teardown of the euro version, send it in on the tip line.

Cruncher: A robotic toy dinosaur dissection

When my children got these interesting and very obnoxious toy dinosaurs last year, I could barely contain my excitement. I knew that one day, they would be on my work bench giving up their secrets. Cruncher is a fairly recent addition to the robotic animal trend that we’ve been seeing the past few years. Imbued with a personality that is a mixture of T-Rex, beagle, and loudmouth jerk, he’s every kids idea of a perfect pet.

[Read more...]

Tearing down a colonoscopy pill camera

Normally, colonoscopies are rather invasive affairs. Swallowing a small pill with a camera is much more amenable to a patient’s dignity and are seeing increasing usage in colon cancer screening. [Mike] acquired a pillcam from a relative who underwent the procedure and did a teardown to figure out how it works.

To get the video signal out of the body, the pillcam has two contacts that conduct the video signal through the body to stick-on contacts; It’s a more power efficient way of doing things versus a radio transmitter. After opening the plastic and metal capsule, [Mike] found three batteries and an impressively small circuit that contained an array of LEDs, a camera, and what might be a small MCU.

Taking a scope to the electronics in the pill, [Mike] found an impressively complex waveform that sends uncompressed image data to the receiver every few seconds. Although the camera was somewhat destroyed in the teardown, we’re pretty confident [Mike] could decode the image data if he had another… ‘sample.’

[Mike] says if you can ‘retrieve’ another one of these pill cameras, he’ll gladly accept any donations and look into the differences between different makes and models. Just make sure you sanitize it first. After the break you can see [Mike]‘s teardown and the inevitable poop jokes in the comments. One last thing – if you’re over 50, doctors should be looking at your colon every 5 or 10 years. Get screened.

[Read more...]

Tearing down a failed LED bulb

todd-harrison-led-bulb

[Todd Harrison] was thinking of replacing some incandescent light bulbs in his house with LED models, so and his wife picked up a single candelabra bulb to test before they spent the cash to swap them all out. The bulb died in about a week’s time, so [Todd] got out his trusty electronic disassembly device (his hammer), sharing his post-mortem examination with us.

After taking a cursory look at it, [Todd] found that the circuit powering the bulb was not overly complicated. A small bridge rectifier along with a few caps and resistors are all that was used to power the device, making it’s failure a bit puzzling. When [Todd] wired it up to his power supply, the bulb lit up, much to his surprise. His best guess as to why it died is that the shrink wrap around the PCB managed to cause a short, though he also noticed that one of the bridge rectifier’s legs was not soldered down.

He started tooling with the light to find out more about it, but he managed to blow out a handful of LEDs in the process. All in all the LED lighting swap was a disappointment, but at least he had some fun along the way!

Continue reading if you’re interested in seeing [Todd’s] diagnosis in its entirety.

[Read more...]

The Gauntlet: A 1 Watt Laser Module

This is the gauntlet; a place where things are tortured in ways that only an engineer could appreciate.

Today’s victim is a 1.0W green laser module, manufactured by Suzhou Daheng under the brand name “DHOM”.

As far as Chinese laser manufacturers go, Suzhou Daheng is about one rung lower than CNI in terms of quality. Although US companies like Coherent blow these guys out of the water, both are still reputable nonetheless.  As far as Chinese lasers themselves go, this one seems a bit conservatively rated; a nice change from the “1000MW 532nm laser cat toy burning module” that’s not too uncommon on dealextreme and the like.

More after the break…
[Read more...]

3d printer software tutorials

It’s no secret that the 3D printer community is extremely fragmented. With three models of RepRaps, three printer kits from Makerbot, and hundreds of ‘printers of the week,’ it’s extremely frustrating for beginners to wrap their heads around the pros and cons of each machine. The software for these printers is segmented nearly as much as the hardware itself, but thankfully [Mike] has put up a series of videos so beginners can wrap their head around all the software packages.

[Mike] used Alibre 3D CAD software to generate the .stl files for all his printable objects. These .stl files were converted into printer-readable GCode by the very popular Skeinforge. The GCode is sent over to [Mike]‘s SUMPOD with ReplicatorG, an awesome program that serves as the front end to a printer.

Although we’d like to see a tutorial for Sfact, the new hotness in .stl to GCode conversion, [Mike] does a very good job at breaking down the complexity of Skeinforge into manageable bites.