Building A Miniature X-ray Tube

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We’ve seen homemade x-ray devices and we’ve seen people making vacuum tubes at home. We’ve never seen anyone make their own x-ray tube, though, and it’s doubtful we’ll ever see the skill and craftsmanship that went into this build again.

An x-ray tube is a simple device; a cathode emits electrons that strike a tungsten anode that emits x-rays. Most x-ray tubes, though, are relatively large with low-power mammography tubes being a few inches in diameter and about 6 inches long. In his amazing 45-minute-long video, [glasslinger] shows us how to make a miniature vacuum tube, a half-inch in diameter and only about four inches long.

For those of you who love glass lathes, tiny handheld spot welders and induction heaters, but don’t want your workshop bathed in x-rays, [glasslinger] has also built a  few other vacuum tubes, including a winking cat Nixie tube. This alternate cat’s eye tube was actually sealed with JB Weld, an interesting technique if you’d ever like to make a real home made tube amp.

Geiger Counter Tells You If Your Dishes Are Radioactive

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[Henrik] really turned out a nice little Geiger counter board based on a cold war era Geiger tube.

It works in much the same way as other projects along the same lines. It does run on batteries if needed, which is no small feat since the tube wants high voltage to operate correctly. And the video after the break shows it spitting out readings to a terminal window when connected to a computer via USB.

But what really caught our eye is the radioactive source material he used for testing. Since he didn’t have anything on hand he had to order something, and ended up going with a couple shards from a dinner plate. A radioactive dinner plate to exact and it’s a brand name you’ve probably heard of before. Red Fiesta Ware apparently used to be radioactive. It’s even mentioned in the intro to the Wikipedia article. Go figure!

One other thing we noticed was [Henrik’s] method of interfacing his multimeter with a breadboard. One of the project photos shows the probe with thin wire wrapped around the tip. We assume this is to make it easy to plug into the breadboard.

Despite this little digression away from the main project we did really enjoy learning about his build. And you can see him showing it off in the clip after the break.

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Hand Placing Flash Die To Make USB Drives

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It’s a stretch to call this one a hack, but USB thumb drives are around us constantly and we always assumed that the boards inside were machine populated (like with a pick and place machine). [Bunnie] tells us otherwise. He recently had the chance to tour a factory where USB flash drives are made.

The image above shows a worker populating a set of boards with the flash memory dies. The waffle-grid to the right holds the dies. Each is a tiny glint of a component. The worker is not in a clean room, and is using a bamboo tool to pick up the pieces. [Bunnie] explains that he’s seen the tools before but doesn’t fully comprehend how they work. He figures that the hand-cut manipulator has just the right amount of grab to pick up the die, but will also release it when it touches down on the dot of glue applied to the landing zone on the board.

If you’re into this sort of thing you should check out the PCB factory tour we saw a couple of years back. The article link is dead but the embedded tour video still works.

[Thanks pl]

High Speed Circuit Design For Quantum Physics Light Sensing

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[Limpkin] designs circuits for a living. This board is one of his recent projects, and although his skills are light years ahead of our own experiences, he did a pretty good job of explaining how he put this board together.

He was tasked with measuring the light intensity of two photodiodes. The expected impulses picked up by those components will be less than a nanosecond in duration, putting some special design constraints upon him. To register this signal he’s using three cascading op-amps per input. To ward off false readings from RF interference he also designed in the shielding which you see surrounding the majority of the circuit.

His package choice for the THS3202 op-amps is quite interesting. He didn’t go with the footprint that includes a thermal pad to dissipate heat because he didn’t want to interrupt the ground plane on the underside of the board. To keep the parts from melting he added an aluminum spacer that contacts the top of the package, then a heat sink that covers the entire shield frame. In a future revision he figures he’ll move to a four-layer board so that the can opt for the MSOP package that does the work for him.

Gamma-ray Scintillation Probe In A Paint Can

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The [Prutchi] family sounds pretty cool. [David], the father, is a well educated engineer, has 70 patents, and has written two books. On his off time, he has a passion for making experimental physics accessible to the average Joe. His daughter [Shanni] is a high school student who co-authored one of those same books, and helps conduct research in the fields of Radio-Astronomy and Quantum Physics. Together, they came up with an affordable, yet very sensitive, gamma-ray scintillation probe for their customized Civil Defense V-700 radiation survey meter. Sweet.

They decided to use parts that were low cost and readily available so others could easily follow in their footsteps. A Philips XP5312/SN photomultiplier tube (PMT) and scintillation plastic are the main components.  The enclosure for the probe is a standard paint can, lined with polyurethane foam inserts to help protect the assembly and hold everything in place.

[David] says that since the probe is very portable and has a high level of sensitivity, it is an ideal candidate for radioactive mineral surveying and scouting miscellaneous gamma-ray sources. They documented the whole process and have compiled a handy PDF file for those who are interested in creating their own.

DIY PC To Telescope Interface Cable

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If you’re serious about astronomy these days, you want to have a computer controlled telescope. Although you can easily purchase a pre-made cable that connects the two devices, where’s the fun in that? [Charles], being an avid Maker, has created a nice step by step guide so you can build your own.

This is a great weekend project, and one that even a novice electronics hobbyist should be able to tackle. It’s straight forward, rather quick, and very easy. Strip some insulation off both ends of the cable, then cut off the unneeded wires. (You’ll only be working with three of them.) Prep everything with heat shrink tubing. Crimp one end of the wires into an RJ10 plug, then solder the other end of the wires into a DB9 connector. Secure the heat shrink tubing in place, attach the housings, and you can call it finished!

[Charles] said the whole procedure only took him around 15 minutes. Total cost? Less than $17 in parts.

Words Of Wisdom From A Maker Entrepreneur

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Have an awesome invention that you want to create and sell to the world? Think you have everything all planned out and you’re ready to just let the money flow in? Maybe not. Take a few moments and read [Jonathan]’s first hand experience of a maker start up business that didn’t go anything like he had planned.

[Jonathan] thought he was ready. He had created a unique product and, by taking pre-orders, didn’t have to front any of his own capital. He had shown that there was demand for such a device. The big problem…supply. Selling things was the easy part. Actually making them was another story. Every step of the way had complications. Printing errors, parts suppliers backed out, an international money transfer didn’t go through, postage rates increased, suppliers sent the wrong parts, and he and his wife had a baby. His stress levels were through the roof knowing that his customers had prepaid and were waiting through all the delays.

In the end, [Jonathan] learned a lot and survived the journey. He is currently working on his next invention. If you’d like to learn more about his experiences, you can message him personally.  There’s also a Pianocade features video after the break.

[via Adafruit]

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