A 3D Printed Junction Transistor Model

Transistors are no doubt one of humankinds greatest inventions. However, the associated greatness brings with it unprecedented complexity under the hood. To fully understand how a transistor works, one needs to be familiar with some Quantum Mechanics! As perhaps any EE undergraduate would tell you, one of the hardest subject to fathom is in fact semiconductor physics.

A good place to start to comprehend anything complex is by having an accurate but most importantly, tangible model at hand. Semiconductors are hard enough to describe with elaborate mathematical tools, is a physical model too much to ask?

[Chuck] has designed, printed and explained the workings of a BJT transistor using a 3D printed model. We really like this model because it goes a long way to shed light on some of the more subtle features of BJT transistors for beginners.

For example, the simplest “electronic switch” model completely ignores the application of a transistor as a linear amplifier and cannot be used to explain important transistor parameters such as hfe (DC current gain Beta) or the VBE (voltage to forward bias the base-emitter junction). [Chuck’s] model on the other hand certainly offers better intuition on these, as the former can be linked to the length of the levers arm and the latter to the minimum force needed to rotate the lever. The Tee structure even signifies the combination of base current with the collector current during operation!

If physical models are not your thing, the classic pictorial depiction, the “Transistor Man” in the Art of Electronics might be of interest. If you’ve even outgrown that, its time to dig into the quantum mechanics involved.

SHACamp 2017, A Personal Review

There are a series of stages to coming down from a festival. After the hectic rush of travel there are the several days of catching up on lost sleep and picking up the threads of your life again, then once a semblance of order has been regained there’s that few weeks of emptiness. Your life will never be the same again, it’s all so mundane.

It’s now a couple of weeks since the SHACamp 2017 hacker festival in the Netherlands was in full swing, and the write-up below has slowly taken shape over that time amid the other work of being a Hackaday scribe and editor. It’s early morning here in Southern England as I write this, so on the equivalent day while I was at SHACamp at this time I would have been carrying a large pack of stickers for distribution on the swapping table through the rising sunlight of a camp still largely asleep after the previous night’s revelry. Past our German and Dutch immediate neighbours, down the ramp from the dyke, the cardboard tent depot on my left and the food court on my right, to the information tent. Greet the bleary-eyed volunteer at the end of their graveyard shift, and spread plenty of Hackaday and Tindie stickers on the table for the masses. And then? Find a coffee, and sally forth into the field for another day among one of the most stimulating communities on Earth. My community. Your community.

The sticker table is a good place to start if you wish to get a handle on a large hacker camp. On it you will find the logos of a cross-section of the diverse organisations and groups present. There are a few commercial ones like my Jolly Wrenchers and Tindie the puppy, there are some from voluntary organisations or interest groups, but mostly they are the logos of a continent’s — even the wider world’s in some cases —  hackspaces and makerspaces. Here you see the breadth of the attendees, as the logos of spaces from thousands of miles away you’ve never encountered before mingle. This isn’t quite a global gathering, but there is a sense of global community around it.

How Do You Describe a Hacker Camp?

So before I take you through my experience of SHA, it’s best to start by describing a hacker camp in more general terms. When I’m describing a camp like SHA to the kind of people who don’t read Hackaday, I put it as similar to the music festivals they are used to but without the bands. Instead the audience provides the entertainment through the work they bring to the event or do at the event, and through a comprehensive program of talks and lectures. Oh — and this is the bit that makes their eyes open wide — every structure on site from the smallest one-man tent to the largest marquee has mains power and high-speed Internet. Sometimes people grasp what SHA is from this description, sometimes they don’t.

Different groups, be they individual hackspaces, people from a particular country, or other special interest groups, congregate in villages, collections of tents, marquees, and gazebos in which they set up whatever cool stuff they’ve brought along. My tent with its Hackaday flag was in a village composed of a mix of British hackspaces up on the dyke, which [Michael] from MK Makerspace had marked with a sign consisting of a huge BS1363A mains plug. More than one person pointed out it would have been better lying flat on the ground with pins in the air, ready to catch an unwary Monty Python foot.

Wooden Word Wristwatch Wows Woomies

[HakuG] wanted to make a watch for his roommates, and had a design project due. He killed two birds with one stone, and then some. The result is a classic word clock, but with a refined all-wood look that’s also small enough to wear on your wrist.

Nothing good ever comes out right the first time, and the log of [HakuG]’s different versions is full of different attempts, all of them just fine in their own right, but none of them “perfect”. Kudos to [HakuG] for sticking with it and refining the project far past the initial prototype stage to something that really looks like a finished product.

Of course we’ve covered word clocks before. Heck, we’ve even seen a beautiful wooden one. But we’re pretty sure that this is the first wooden word-clock watch we’ve ever written up, and it’s surely one of the nicest.

Thanks [Paul Hein] for the link!

Quintuple-Sized LEGO Go-Kart

[Matt Denton] was inspired by [James Bruton]’s scaled up LEGO and decided to create his own giant LEGO project. He found a classic model that he wanted to scale up.  1985’s Technic Go-Kart (set #1972) contained 98 pieces and seemed manageable.

He wanted to create something his 8yo nephew [Ruben] could sit in, but had to rule out a fully kid-sized go-kart. It had also to be (at least somewhat) economical with regards to plastic and printing time. [Matt] settled on sizing the largest piece—the 2×8 plate—to fit diagonally on the 11”x11” bed of his Lulzbot Taz5.

It took 168 hours to print all 98 parts (some of them in a series of smaller pieces), 5 kilos total of filament at mostly 20% infill. The resulting car can be assembled and disassembled just like LEGO—no glue! The rack and pinion steering actually works and the Ninjaflex-tired wheels roll as one would expect. So, pretty much the same as the real model only five times bigger. The only non-LEGO components are threaded rods down the middle of his cross axles as well as the hose, just Neoprene hosing from a hardware store.

[Matt] is well-known to Hackaday readers, being one of the original BB-8 builders as well as co-creator of the Mantis walking robot. He’ll be on hand this weekend in Maker Faire Hannover to share this project, Mantis, and others. Continue reading “Quintuple-Sized LEGO Go-Kart”