The Fab Lab Next Door: DIY Semiconductors

You think you’ve got it going on because you can wire up some eBay modules and make some LEDs blink, or because you designed your own PCB, or maybe even because you’re an RF wizard. Then you see that someone is fabricating semiconductors at home, and you realize there’s always another mountain to climb.

We were mesmerized when we first saw [Sam Zeloof]’s awesome garage-turned-semiconductor fab lab. He says he’s only been acquiring equipment since October of 2016, but in that short time he’s built quite an impressive array of gear; a spin-coating centrifuge, furnaces, tons of lab supplies and toxic chemicals, a turbomolecular vacuum pump, and a vacuum chamber that looks like something from a CERN lab.

[Sam]’s goal is to get set up for thin-film deposition so he can make integrated circuits, but with what he has on hand he’s managed to build a few diodes, some photovoltaic cells, and a couple of MOSFETs. He’s not growing silicon crystals and making his own wafers — yet — but relies on eBay to supply his wafers. The video below is a longish intro to [Sam]’s methods, and his YouTube channel has a video tour of his fab and a few videos on making specific devices.

[Sam] credits [Jeri Ellsworth]’s DIY semiconductor efforts, which we’ve covered before, as inspiration for his fab, and we’re going to be watching to see where he takes it from here. For now, though, we’d better boost the aspiration level of our future projects.

Continue reading “The Fab Lab Next Door: DIY Semiconductors”

[Dave’s] Not Just a Member of the Air Club for Tweezers

We are always surprised how much useful hacking gear is in the typical craft store. You just have to think outside the box. Need a hot air gun? Think embossing tool. A soldering iron? Check the stained glass section. Magnification gear? Sewing department.

We’ve figured out that people who deal with beads use lots of fine tools and have great storage boxes. But [Dave] found out they also use vacuum pickup tweezers. He had been shopping for a set and found that one with all the features he wanted (foot pedal, adjustable air flow, and standard tips) would run about $1000.

By picking up a pump used for bead makers and adding some components, he put together a good-looking system for about $200. You can see a video of the device, below, and there are several other videos detailing the construction.

Continue reading “[Dave’s] Not Just a Member of the Air Club for Tweezers”

A DIY Vacuum Pickup Tool for $75

If you’re assembling prototypes of SMD boards on your own, placing the parts accurately can be a pain. Of course, it’d be nice to have a full pick and place machine, but those are rather expensive and time consuming to set up, especially for a small run of boards. Instead, a vacuum pickup tool can help you place the parts quickly and accurately by hand.

The folks over at Ohmnilabs have put together their own DIY pickup tool for about $75, and it’s become part of their in-house prototyping process. They grew tired of placing components with tweezers, which require you to remove parts from the tape before lifting them, and have a tendency to flip parts over at the worst time.

The build consists of a couple parts that can be bought from Amazon. An electric vacuum pump does the sucking, and the vacuum level is regulated with an adjustable buck converter. A solid foot switch keeps your hands free, and syringe tips are used to pick the parts up.

This looks like a simple afternoon build, but if you’re prototyping, it could save you tons of time. To see it in action, check out the video after the break.

Continue reading “A DIY Vacuum Pickup Tool for $75”

A Glimpse Into The Mind Of A Robot Vacuum Cleaner

What’s going through the mind of those your autonomous vacuum cleaning robots as they traverse a room? There are different ways to find out such as covering the floor with dirt and seeing what remains afterwards (a less desirable approach) or mounting an LED to the top and taking a long exposure photo. [Saulius] decided to do it by videoing his robot with a fisheye lens from near the ceiling and then making a heatmap of the result. Not being satisfied with just a finished photo, he made a video showing the path taken as the room is being traversed, giving us a glimpse of the algorithm itself.

Looking down on the room and robot
Looking down on the room and robot

The robot he used was the Vorwerk VR200 which he’d borrowed for testing. In preparation he cleared the room and strategically placed a few obstacles, some of which he knew the robot wouldn’t get between. He started the camera and let the robot do its thing. The resulting video file was then loaded into some quickly written Python code that uses the OpenCV library to do background subtraction, normalizing, grayscaling, and then heatmapping. The individual frames were then rendered into an animated gif and the video which you can see below.

Continue reading “A Glimpse Into The Mind Of A Robot Vacuum Cleaner”

How to Measure the Dielectric Constant for DIY Capacitors

Every now and then you need to make your own capacitor. That includes choosing a dielectric for it, the insulating material that goes between the plates. One dielectric material that I use a lot is paraffin wax which can be found in art stores and is normally used for making candles. Another is resin, the easiest to find being automotive resin used for automotive body repairs.

The problem is that you sometimes need to do the calculations for the capacitor dimensions ahead of time, rather than just throwing something together. And that means you need to know the dielectric constant of the dielectric material. That’s something that the manufacturer of the paraffin wax that makes it for art stores won’t know, nor will the manufacturers of automotive body repair resin. The intended customers just don’t care.

It’s therefore left up to you to measure the dielectric constant yourself, and here I’ll talk about the method I use for doing that.

Continue reading “How to Measure the Dielectric Constant for DIY Capacitors”

The Art of Making A Nixie Tube

Three years ago we covered [Dalibor Farnby]’s adventures in making his own Nixie tubes. Back then it was just a hobby, a kind of exploration into the past. He didn’t stop, and it soon became his primary occupation. In this video he shows the striking process of making one of his Nixie tubes.

Each of his tubes get an astounding amount of love and attention. An evolution of the process he has been working on for five years now. The video starts with the cleaning process for the newly etched metal parts. Each one is washed and dried before being taken for storage inside a clean hood. The metal parts are carefully hand bent. Little ceramic pins are carefully glued and bonded. These are used to hold the numbers apart from each other. The assembly is spot welded together.

In a separate cut work begins on the glass. The first part to make is the bottom which holds the wire leads. These are joined and then annealed. Inspection is performed on a polariscope and a leak detector before they are set aside for assembly. Back to the workbench the leads are spot welded to the frame holding the numbers.

It continues with amazing attention to detail. So much effort goes into each step. In the end a very beautiful nixie tube sits on a test rack, working through enough cycles to be certified ready for sale. The numbers crisp, clear, and beautiful. Great work keeping this loved part of history alive in the modern age.

Continue reading “The Art of Making A Nixie Tube”

Cheap Vacuum Source For Working With Dangerous Chemicals

[Nurdrage] puts out a lot of neat videos, mostly about home chemistry. For the home chemist it is occasionally desirable to pull a vacuum. For example, a potentially dangerous chemical can be boiled and distilled at a much lower temperature than at atmospheric pressures.

However, there’s a problem with just going to the local import store and buying the first vacuum pump on the shelf.  They are primarily designed for atmospheric gasses and tend to melt when exposed to solvents. If you’re a big university or a commercial lab this is no problem. You just drop three grand on a Teflon diaphragm pump or a liquid nitrogen trap. For the home chemist who’s already having enough trouble just buying the chemicals needed for neat experiments, this is not an option.

[Nurdrage] demonstrates the proper usage of a much cheaper option: an aspirator vacuum pump. You might remember something similar from high school chemistry. School pumps generally use flowing tap water to produce the vacuum. [Nurdrage] is saving water by using a fluid pump and a reservoir to drive his aspirator.

Aspirator pumps use the Venturi effect to create a vacuum. These devices are cheap because there are no moving parts. We looked it up and the one he is using costs ten US dollars on fleabay. It can pull enough vacuum to boil water below room temperature.

The video is really good and provides a lot of useful information. It also seems like a really useful device for other hacking tasks outside of home chemistry. Video after the break.

Continue reading “Cheap Vacuum Source For Working With Dangerous Chemicals”