While originally designed to put light where the sun don’t shine for medical purposes, [Nava Whiteford] says the Wolf 5151 Xenon endoscopic light source also works well for microscopy and general optical experiments, especially since you can get them fairly cheap on the second hand market. His cost just $50 USD, which is a steal when you consider a replacement for its 300 watt Olympus-made bulb will run you about 200 bucks alone.
That said, [Nava] recently moved on to a more compact light source, and figured that was a good enough excuse to crack open the Wolf 5151 and see what makes it tick. In this particular post he’s just looking at the optical side of things, which is arguably the most interesting aspect of the device. Helpfully, the whole assembly is mounted to its own sled of sorts that can be pulled from the light source for a closer examination.
Beyond that expensive bulb we mentioned earlier, there’s a thick piece of what appears to be standard plate glass being used as an IR and UV filter. [Nava] suspects this component is responsible for keeping the rest of the optics from overheating, which is backed up by the fact that the metal plate its mounted to appears to feature a K-type thermocouple to keep an eye on its operating temperature. Forward of that is a unique aspheric lens that features a rough spot to presumably scatter the light at the center of the beam.
Our vote for the most fascinating component has to go to the Neutral Density (ND) filter, which is used to control the intensity of the light. In a more pedestrian light source you could just dim the bulb, but in this case, the Wolf 5151 uses a metal disk with an array of holes drilled into it. By rotating the disc with a DC motor, the lens can be variably occluded to reduce the amount of light that reaches the aperture, which connects to the fiber cable.
Over the years we’ve seen several attempts at adding Internet connectivity to the lowly wired doorbell. Generally, these projects aim to piggyback on the existing wiring, bells, and buttons rather than replace them entirely. Which invariably means at some point the AC wiring is going to need to interface with a DC microcontroller. This is often where things get interesting, as it seems everyone has a different idea on how best to bridge these two systems.
That’s the point where [Ben Brooks] found himself not so long ago. While researching the best way to tap into the 20 VAC pumping through his doorbells, he found a forum post where somebody was experimenting with optocouplers. As is unfortunately so often the case, the forum thread never really had a conclusion, and it wasn’t clear if the original poster ever figured it out.
[Ben] liked the idea though, so he thought he would give it a shot. But before investing in real optocouplers, he created his own DIY versions to use as a proof of concept. He put a standard LED and photoresistor together with a bit of black tape, and connected the LED to the doorbell line with a resistor. Running the LED on 60 Hz AC meant it was flickering rapidly, but for the purposes of detecting if there was voltage on the line, it worked perfectly.
Wanting something slightly more professional for the final product, [Ben] eventually evolved his proof of concept to include a pair of 4N35s, a custom PCB, and a 3D printed enclosure. Powered by a Particle Xenon, the device uses IFTTT to fire off smartphone notifications and blink the lights in the house whenever somebody pushes the bell.
Star Trek — as much as we love it — was guilty sometimes of a bit of hyperbole and more than its share of inconsistency. In some episodes, ion drives were advanced technology and in others they were obsolete. Make up your mind!
The ESA-JAXA BepiColombo probe is on its way to Mercury riding on four ion thrusters developed by a company called QinetiQ. But unlike the ion drive featured in the infamous “Spock’s Brain” episode, BepiColombo will take over seven years to get to Mercury. That’s because these ion drives are real.
The craft is actually two spacecraft in one with two different Mercury missions. The Mercury planetary orbiter will study the surface while the magnetosphere orbiter will study the little planet’s magnetic field. Check out a video about the mission, below. The second video shows [Neil Wallace] talking about how the ion propulsion — also known as solar electric engines — differ from traditional chemical thrusters.
Particle, makers of the WiFi and Cellular IoT modules everyone loves, is introducing their third generation of hardware. The Particle Argon, Boron, and Xenon are Particle’s latest offering in the world of IoT dev boards, and this time they’re adding something amazing: mesh networking.
The three new boards are all built around the Nordic nRF52840 SoC and include an ARM Cortex-M4F with 1MB of Flash and 256k of RAM. This chip supports Bluetooth 5 and NFC. Breaking the new lineup down further, the Argon adds WiFi with an ESP32 from Espressif, the Boron brings LTE to the table with a ublox SARA-U260 module, and the Xenon ditches WiFi and Cellular, relying only on Bluetooth, but still retaining mesh networking. This segmentation makes sense; Particle wants you to buy a ton of the Xenon modules to build out your network, and use either the Argon or Boron module to connect to the outside world.
The form factor of the boards conforms to Adafruit Feather standard, a standard that’s good enough, and much better than gigantic Arduino shields with offset pins.
Of particular interest is the support for mesh networks. For IoT solutions (whatever they may be), mesh networking is nearly a necessity if you have a sufficient number of nodes or are covering a large enough area. The technology going into this mesh networking is called Particle Mesh, and is built on OpenThread. While it’s a little early to see Particle’s mesh networking in action, we’re really looking forward to a real-world implementation.
Preorder pricing for these boards sets the Argon module at $15, the Boron at $29, and the Xenon at $9. Shipping is due in July.
In the past half-century, lasers have gone from expensive physics experiments using rods of ruby to cheap cutting or engraving tools, and toys used to tease cats. Advances in physics made it all possible, but it turns out that ruby lasers are still a lot of fun to play with, if you can do it without killing yourself.
With a setup that looks like something from a mad scientist movie set, [styropyro]’s high-powered laser is a lot closer to the ray gun of science fiction than the usual lasers we see, though hardly portable. The business end of the rig is a large ruby rod nestled inside a coiled xenon flash lamp, which in turn is contained within a polished reflector. The power supply for the lamp is massive — microwave oven transformers, a huge voltage multiplier, and a bank of capacitors that he says can store 20 kilojoules. When triggered by a high-voltage pulse from a 555 oscillator and an old car ignition coil, the laser outputs a powerful pulse of light, which [styropyro] uses to dramatic effect, including destroying his own optics. We’d love to hear more about the power supply design; that Cockcroft-Walton multiplier made from PVC tubes bears some exploration.
Whatever the details, the build is pretty impressive, but we do urge a few simple safety precautions. Perhaps a look at [Ben Krasnow]’s 8-kJ ruby laser would help.
Wafer level chips are cheap and very tiny, but as [Kevin Darrah] shows, vulnerable to bright light without the protective plastic casings standard on other chip packages.
We covered a similar phenomenon when the Raspberry Pi 2 came out. A user was taking photos of his Pi to document a project. Whenever his camera flash went off, it would reset the board.
[Kevin] got a new Arduino 101 board into his lab. The board has a processor from Intel, an accelerometer, and Bluetooth Low Energy out of the box while staying within the same relative price bracket as the Atmel versions. He was admiring the board, when he noticed that one of the components glittered under the light. Curious, he pulled open the schematic for the board, and found that it was the chip that switched power between the barrel jack and the USB. Not only that, it was a wafer level package.
So, he got out his camera and a laser. Sure enough, both would cause the power to drop off for as long as the package was exposed to the strong light. The Raspberry Pi foundation later wrote about this phenomenon in more detail. They say it won’t affect normal use, but if you’re going to expose your device to high energy light, simply put it inside a case or cover the chip with tape, Sugru, or a non-conductive paint to shield it.
The Homestake Mine started yielding gold in 1876. If you had asked George Hearst, the operator at the time, if the mine would someday yield the secrets of the universe I bet he would have laughed you out of the room. But sure enough, by 1960 a laboratory deep in the mine started doing just that. Many experiments have been conducted there in the five and a half decades since. The Large Underground Xenon (LUX) experiment is one of them, and has been running is what is now called the Sanford Underground Research Facility (SURF) for about four years. LUX’s first round of data was collected in 2013, with the experiment and the rest of the data slated to conclude in 2016. The method, hardware, and results wrapped up in LUX are utterly fascinating.