Tindie

Long before tiny OLED modules became commonplace, 7-segment displays did the job of showing users numerical data, as well as a somewhat limited alphabet. Of course, they’re still in use today and a quick and fun exercise to add to projects that need simple output. If you want to move beyond the ordinary, look into larger 7-segment displays.

Typcially one of these digits will be the size of your little fingernail. But there are other options out there. Here’s a kit that mates a larger 7-segment display with a driver backpack. It uses a transistor array to sink the current for each segment. The result is a single digit that is switches the segments serially and can be chained to more digits.

These display kits stand 45 millimeters (1.75 inches) tall when assembled. They might not make good components for a basketball display, but are quite a bit larger than standard. These are modules and it becomes more difficult to locate stock items as you get bigger than this. For instance there’s a 12″ over at Evil Mad Scientist but they’re non-stock and the price begins to add up. Foyard has a 5″ module (PDF) but trying to find a source in small quantities is an impossibility. If you really want to go big, consider building your own with an infinite amount of patience.

Digits, along with the decimal point, are changed via a shift register, which can be controlled using an Arduino. Example code and more information can be found on renewable energy innovation’s website.

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If you have an office job, chances are very high that you spend a lot of your time using a keyboard and mouse. Many of us never really think about these critical interface devices, but without them, many jobs wouldn’t be possible, or at least would be very different.

Personally, I started using a trackball a few years ago, and recently started using a relatively inexpensive mechanical keyboard. Though not that unique, they hopefully improve my efficiency somewhat.

If you’re already looking for out of the ordinary peripherals like mechanical keyboards, perhaps you’d like something absolutely unique. If that’s the case, you could make your own computer mouse, as seen in kit form here. The kit provides parts for a mouse, including a top shell and bottom base plate, as well as wiring and screws. You’ll just need to provide an Arduino board to interface between the mouse and a computer.

Alternatively, you could print your own with files for this mouse, which can be found on Thingiverse. You’d need to provide your own electronics, but the optical sensor board used in the kit can be found here, so it should work nicely.

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If you like to browse around on Tindie to see what is available, you’ll find sections full of interesting and unusual items. For me at least, that’s part of the fun of writing for this site.

The Sound section, which as of this writing has six pages of acoustic goodness, seems especially popular listing-wise. And why not? Making music is all about creativity, and if you can build your own instrument and/or accessory, what could be more creative?

On the other hand, after getting a DSLR and gradually getting better and better (less worse?) at controlling my camera for good and/or experimental effects, I have to report that there is only one page of Camera Equipment listings. What’s there looks really neat, much of it involving using a GoPro camera at extreme depths, but certainly it would be a great place for lighting, custom intervlometers, or even a light painting robot, like the one seen in the video below:

The great thing about this from a seller’s perspective, is that if you do want to list your camera hack, it won’t have as much competition as some other items!

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Polar plotters, AKA polargraphs, are devices that print on a vertical surface, based on the length of two strings holding a drawing instrument. Unlike a traditional CNC setup, where there are independent X and Y axes, polar plotters use a combination of the length of these lines and trigonometric relationships to determine a point on a whiteboard or other surface.

Thinking about this more, when I, and other students were in high school or middle school, it was hard to see why we needed to take algebra, or trigonometry. After graduating from engineering school and getting a job in the “real world” however, the need to know these concepts really well became obvious when designing certain parts and figuring out control schemes.

A polar plotter is a great way to show students that this kind of relatively complex math is actually quite useful in certain situations. I featured the Makelangelo plotter here in February, but another exciting solution, that almost seems specifically made for a classroom setting, is the gocupi, seen in the video below. It uses two suction cups to anchor the pulling motors, and attaches directly to a Raspberry Pi for control.

Now, if you’d like to illustrate to kids and/or college students why calculus is necessary, you might find that a little more challenging!

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Do you like soldering PCBs? Personally, I’d choose a terminal connector any time over having to deal with soldering (check out Wednesday’s post about ESP8266 screw terminals). This may be due in part to my equipment though, including a cheap helping hand device which doesn’t hold PCBs too well.

If you have to deal with soldering PCBs quite a bit, or if you even enjoy it, then this PCB Rax circuit board holder by Bench Werx looks like it would make the job much, much easier. It can hold rectangular boards up to 9-1/4″ x 8″, and if you need to build/repair something even bigger, the connecting rods can be replaced.

Where it really shines though is that it has extension brackets that are designed to hold oddly shaped boards, like the Christmas tree seen above. Once you have things roughly fastened together with the extension brackets, the threaded rods that connect the two halves of this device can be tightened further without hand tools. Additionally, the device can be set in a vertical or horizontal position, allowing you to work on projects in ergonomic comfort to your heart’s content!

Check it out in the video below. It looks much better than the tools I normally use; perhaps it could even convert solder-haters into solder-tolerants!

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If you want to build a CNC router, laser cutter, or other setup, you’ll generally need some sort of gantry system, stepper motors, a control board, and… wait for it… a computer with a parallel port. Yes, that’s right, many of the CNC controllers used today (including my own actually) still use a parallel port for control. And if you’re thinking you can just use a USB to parallel port adapter, I’ve found from personal experience that that doesn’t really work (though a PCI parallel port does).

The other popular option is a grbl-based solution, which runs on an Arduino and needs to be assembled from a variety of components. Tindie seller “Class B Project” thought there needed to be a better way to do this, and created an all-in-one solution with his motionPro 3+1 axis CNC controller.

This device can control up to four stepper motors, giving you the ability for X, Y, Z, and even a fourth axis if your setup is that advanced. Alternatively, you can clone one of these axes in order to control two motors, which can be useful in some situations. The board communicates via USB and a Bluetooth module can even be added for wireless control!

You can see this setup controlling a CNC laser cutter/engraver in the video below:

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If you’re going to work with electronics, you may have accepted the fact that you’ll need to solder components together. On the other hand, I can’t be the only one that finds this to be more of an annoyance than anything. Not only do you have to wait for your iron to heat up and make sure to unplug it afterwards so as not to cause a fire, you also need to get and keep wires in the proper position so they can be bonded together.

The good news is that there are alternatives. If you have the wherewithal, much of the work can be done using robots, and there are “helping hands” products that make the job easier. In certain situations, I’m a big fan of screw terminals, or even spring terminals, where you simply have to open them up, insert a wire, and release it so that its firmly held. Admittedly, it helps if you’ve applied ferrules or tinned the wires, but let’s not get ahead of ourselves.

These connections are common in industrial applications, but we’re seeing this method filter into maker applications more and more. I wrote about an Arduino screw terminal shield previously, and now there is one that can add these connections to the ESP8266 WiFi module. Given my previous rant, perhaps there is some irony in the fact that it can be had fully assembled or as a kit/just a PCB, meaning in those cases that you’ll need to solder it together. On the other hand, something like that would allow it to be ready to go when needed, perhaps in an application where you don’t have power for an iron available.

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Randomness is an interesting concept. If you were to flip a coin or roll dice, you’d expect random results. However, there is some nearly undetectable bias based on the construction of these objects and the person doing the flipping/rolling. The same concept applies to computer systems, which need to create random numbers for encryption and other functions.

In order to obtain random values, computers can keep a “pool” of random values to use as needed. In the Linux operating system this pool is only 4 kiloBytes in size, and is replenished using external sources such as keyboard timings and mouse movements. When used, this pool has to be replenished, which can take time.

If you need more randomness in your computing, the TrueRNG V3 USB number generator produces more than 400 kilobits per second of true random numbers. This can fill up the Linux entropy pool extremely quickly, allowing you to run applications for security, gaming, or simulations without delay.

A Random Pattern Generated with TrueRNG

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Regan’s NAS case cooling fan duct

Yes, that’s right, “Patshead.com” has a Tindie store. I’ve been following him on Twitter for a while and thought that anyone using a spinning head as his Twitter icon had to be worth getting to know. When I pinged him for an interview, he let me know that he’d be interested in an interview, but was, “A little worried that [he’d] be completely the opposite of the average Tindie user.” Obviously was going to be interesting!

First of all, I needed to know where Pat’s head came from.

I don’t remember all the exact details.  A bunch of us from work used to sometimes gather at a bar/restaurant that was between two of our offices.  This was back in ’99 or 2000.  We somehow get very excited about the idea of turning my head into a spinning gif, and we got the idea that I should register patshead.com.  For most of its life, patshead.com just hosted my email, some makeshift photo galleries, and a page with not much more than my spinning head.

I still get terribly excited when a website or social media network spins my head.  I’m still grandfathered in with an animated gif on Twitter.  Our makerspace, TheLab.ms in Plano, is very active on Meetup, and our pages on Meetup are often teeming with tiny spinning heads.  When new people show up in person, I often hear, “I recognize you!  You’re the spinning head on half of the Meetups!”

Though perhaps a little offbeat by “normal” standards, Pat seems like exactly the type of person that might sell on (or write for) Tindie. How is he different from the average Tindie user?

I’d probably be happier if no one ever bought anything from my Tindie store!  Everything in my store is a 3D printed object that I designed.  All the designs are Open Source.  I’d much rather see people print their own, or find a local makerspace that can help them out.

I wasn’t selling anything for a long time, but I regularly had people reach out to me asking where they could acquire one of my breadboard vises.  I don’t want to be in the business of manufacturing, but I quite enjoy the idea of real people making use of the stuff I design.  With the breadboard vise, I tell people that this is too much money to pay for $1.25 worth of ABS plastic.

Regan’s breadboard spring vise

Talk about a low-pressure sales pitch! So if you want something from Regan’s inventory, just print it yourself. On the other hand, if you don’t want to do that, Tindie presents another alternative!

Since you’re probably wondering:

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I’m a huge fan of electronic music and the colorful “blinky” musical instruments that produce it. On the other hand, I generally don’t have the patience that it takes to truly master one of these devices, or even get enough use out of it to be worth the purchase price. Fortunately, there are all kinds of apps available that can help fill this need at a low or free price.

On the other hand, it’s hard to beat an actual purpose-built object. Even as software tools become better, we see dedicated hardware jumping to fill new roles. A great example of this is the monome, a grid of buttons, each hiding its own LED. It’s obvious use is as a looping controller, but since it appeared, it has been used for a myriad of live-music control tasks.

Here’s a MIDI device that uses an Arduino as the brains of the operation, with 16 WS2812B RGB LEDs to make the pads light up as needed. With just a four by four LED grid, it might be a bit more accessible for novices like myself. If you give it a whirl and decide it’s no longer useful, you could reprogram it to do something different, or perhaps turn the parts into something else!

Personally, I could also see something like this as an amazing robot controller (if you need a backup plan to justify it). On the other hand, it appears to do the job it was designed for—making electronic music—quite well, as seen in the video below.

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