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We’ve all used LED and LCD 7-segment displays in calculators, home theater systems, and the like to show us pertinent information. While useful and extremely common, one alternative you may not have considered is an electromechanical 7-segment display.

These displays could be considered to be a simplified version of the flip-disc or flip-dot displays that were at one time common in mass transit systems, even being used in the game show Family Feud until 1995. In both systems a colored segment is moved into place using mechanical means, and uses no more power until the digits are adjusted once again.

While largely replaced by newer technology, you can still find these displays for sale via a quick web search. Unfortunately, they tend to be quite expensive, so if you’d like to build one using this technology plan on spending several hundred dollars or more on a multi-digit display. But check out the video below and you’ll hear (and see) why they’re so much fun to build into a project. That clicky action is addictive!

The good news is that if you do manage to obtain one or more of these devices, the Sig7Seg i2c controller for this type of device is available at a small fraction of this display’s price. It’s shown in the video taking signals from a Particle Photon, but will also work with a Raspberry Pi, Arduino board, or similar. The hardest part of driving these segments (other than getting your hands on them) is wiring the reversible voltage necessary to change to either state. This driver takes care of that with a port expander and two DMOS transistor array chips.

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Browsing around tech sites, you’ve likely heard the term LoRa, or LoRaWAN thrown around. While you’ve probably established that it’s a long range IoT specificaion, documentation on how to get started with it can be somewhat elusive. Muddying the waters further is that some telecom operators are implementing this type of network, leading to the question of whether you can implement your own private network.

The good news is that this technology operates on the open spectrum, meaning that while you can use a telecom network to help with your LoRa needs, you can also set up your own. For a great way to get started, the Dragino LoRa IoT Kit includes everything you need to set up your own network, including a LoRa gateway, two LoRa shields (one with GPS capabilities), two Arduino Uno clones, and even wiring and sensors to capture data. Importantly, the kit also provides examples to help you get up and running.

While this type of network operates at 50 kbps or less, the claimed transmission range of 5-10km using this system is extremely exciting. While it might not work for VoIP calls, reading a sensor at a distance or giving short commands to a robot are ideal applications!

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We all know that power can be transmitted wirelessly, whether through an exotic arcing setup like you might have seen many years ago in Nikola Tesla’s lab, or with the more modern (yet less spectacular) use of an inductive charging pad used for smartphones. To really understand this inductive charging principle give this wireless power kit from Electromechreation a try.

The device uses a powered coil of wires to wirelessly light up a 1 watt LED, or it can be configured to power an electrical motor. While fun for experimenters, this would also make a really excellent teaching tool for classroom use. You can see an earlier version in action in the video below:

As with some other products found here, this device started out as a Kickstarter campaign. Now it’s on Tindie. Listing here is as simple as making a blog post. If you’re looking for a place to list your crowdfunded items, or even somewhere to boost sales of an established product, why not give selling on Tindie a try?

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Motors01CJC by C_J_Cowie via Wikimedia Commons CCA-SA 3.0

If you like to make things—and you’re reading Tindie’s blog so that seems like a fair assumption—at some point you’ll want to make one of your creations move, likely with a motor of some sort. We can help you decide which kind of motor best fits your application. Read on!

DC Motors

DC motors are the simplest rotary motion devices on this list, as movement is started when sufficient voltage is applied between the positive and negative poles. Speed can be controlled by varying this applied voltage, and direction is changed by reversing input polarity. By default, there is no feedback to tell you how fast this type of motor is going. If needed, an encoder can be added to sense speed, and gear reduction can be used to increase output torque at the expense of rotational speed.

While easy to control, they need more current than an Arduino or similar dev board can generally provide. For an easy way to integrate a motor with this type of control, just do a search for Arduino “motor shield” for lots of options, many of which will also work with the other motor types discussed here.

Stepper Motors

Sometimes confused with servo motors, stepper motors operate by energizing certain coils to make a shaft turn one step at a time. This requires more thoughtful control than a simple DC motor, but also gives it the ability to move in a precisely controlled fashion. While there are many uses for this type of device, one notable use is in CNC equipment. For a great illustration of how one of these work, check out the video above of YouTuber Proto G’s 3D-Printed Stepper Motor.

For CNC control options, if you’re interested in driving one in a laser or plotter project, this board looks interesting. It’s meant for use with the Grbl software package, which has become the de facto CNC control standard for Arduino boards. Alternatively, this shield gives a more general Arduino/Grbl implementation, including a connection point for your Z-axis.

Servomotor

Servomotors, or just servos, come in all shapes and sizes, but feature a feedback loop. This means that if there is an error in the motor’s position, the controller knows about it and can take the proper corrective action. Steppers, while generally extremely accurate, don’t have this ability, and if your system somehow misses a step, all further actions from there on out will be inaccurate until it’s re-homed. For many Tindarians, “servo” is synonymous with the hobby servos that are seen in model airplanes and the like. While these work well in many applications, other models are available that can cost thousands of dollars, many of which can rotate continuously with feedback.

Incidentally, you’ve likely heard that you can modify a servo for continuous rotation. After doing this myself, calling these modified motors “servos” is a bit of a misnomer, as there’s no longer any positional feedback. They are simply DC motors in a convenient format with a modicum of speed control. That being said, if you do need positional feedback, then you can add a Mocoder encoder to one of these modded devices, restoring a sense of control to your system!

Of course there are other electro-mechanical options, such as AC motors, solenoids, and variations of the motors listed here. Hopefully this gives you a good place to start if you’re considering building a new robot or other moving device!

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Makernet Knob’s makes the point that “Rotary encoders are cool but hard to wire into your projects.” Having wired up a custom input device for my computer using an encoder, I can attest to both of these statements. In my case, it took me quite a bit of time simply to figure out how each encoder pin was used!

To help alleviate complicated wiring issues, this custom knob features a built-in I2C interface, which allows several (even hundereds) of knobs to be chained together without issue. Additionally, the top of the encoder can be depressed as a pushbutton, and it even has an RGB LED integrated inside of it to give you feedback right on the knob!

While this device looks very interesting (especially the integrated RGB output), if you’re new to encoders, check out this “Rotary Input Battle” post. Encoders are certainly extremely useful, but sometimes an inexpensive potentiometer will get the job done nicely!

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Little robot friends are, as described, “connected toys for learning code and electronics in a fun way.” They include a capacitive touch sensor, RGB LEDs for eyes, an accelerometer, and several other components to allow them to interact with their environment. They’re powered by what appears to be an ESP WiFi module, and can be programmed via a custom app or via the Arduino IDE.

With three fun designs: Spikey, Ghosty, and Curvy, you have to give Little Robot Friends a ton of credit for making a device that will be interesting to hackers, as well as a more general audience. They’re available assembled here, or for a little less money if you want to solder things together yourself.

One neat feature of these boards is that kids (or adults) can make accessories for them using paper, cloth, and the included stickers. You can even 3D print costumes for them. As engineers and tinkers we tend to think in terms of “does it work?” Putting a little more thought into how things appear, or even how they can be decorated, can really make your device stand out!

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While Tindie has thousands of unique products for you to peruse, for even more, head over to the Flea Market. While less refined customers might see some of the items there as junk, others see surplus items as inspiration for their creativity! Here’s a few interesting items for sale this month:

As-Is Toy Truck with Combustion Engine

“As-is” implies that the machinery doesn’t work, but given the components shown, including an internal combustion engine, this could provide the parts for something very interesting!

Bank Note Validator

Ever wonder how change machines know if you’re stuck a dollar bill in or just a piece of paper? You could try to find the documentation, or for a more hands-on experience, you could take this slot machine unit apart!

15 PSI Pressure Transducer

Need to transmit a pressure reading to your electronics? If you only need to measure up to 15 PSI, here’s just the device for you!

Rainbow Light Show Kit

This no-solder kit allows you to blend RGB LED elements via three proximity sensors. Words don’t really do this device justice; check out the video to see the lighting effects that it can generate.

Whether or not you see something to buy, you may have an item or two languishing in your garage that other Tindiarians would appreciate. Why not list it and make room in your workshop for the next project?

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Of the many innovative clocks that hackers and makers have designed and built, word clocks, which feature a series of letters that light up to literally spell out the time, have to be one of the best combinations of interesting technology and usability. The LEDs underneath each letter give them a nice technical base, while the clever arrangement of letters to form the proper words would make any English teacher proud.

You can see a great example of this type of clock in the video below. Lots of cool ideas for effects and functionality are featured here, such as blinking, letters dropping in, and even an audible voice:

For those of us that are more electrically-minded than mechanical, or if you simply don’t have the tools or time to make a really excellent face, here’s a 40 x 40cm option to get that taken care of. “All” you have to do is supply the electronics and program it. It’s available in Dutch or English depending on your preferred language, and it could even make an excellent instructional tool for a foreign language class.

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The fact that data and power can be supplied via a single USB connection is generally a very good thing. However, PCs are only going to provide 500mA over a USB port unless your device negotiates for more.

A powered USB hub can be a solution to this problem, but for total independent control of power and data lines, this USB Data/power Merger device allows you to plug in the power independently of the data connection between host and device.

The power side comes in the form of a pair of screw terminals, and data is input via a Micro-B USB input. This would be extremely useful in testing scenarios (like brownout testing), and could serve to isolate a charging device from any possibility of data transfer if just the power lines are used.

If this looks interesting, but you need something a little bit different, why not check out some of the other USB breakout boards and power supplies that Tindie offers? There’s also a listing of rather unusual USB breakouts if you don’t find what you need!

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If you attended the World Maker Faire in New York this year, I hope you were able to stop by the Tindie booth. I personally enjoyed meeting everyone, and while it can be exhausting to talk for hours on end, it’s a lot of fun discussing a website/service that you sincerely find interesting. If we didn’t answer the big question of “what is Tindie?” well enough, check out this blog post for further explanation!

Of course, much more was going on in the wider world of the events than just the Tindie booth. I got to visit two Tindie sellers, including Tiny Circuits, which was absolutely packed. They had a gigantic version of their handheld game cabinet set up to play Flappy Bird.

Lumen was also at the Faire showing off their solar powered jewelry. The products are really interesting both from an artistic design perspective, and because they run on a tiny amount of power from a solar cell and capacitor. Tindie the dog was also seen at this exhibit, cleverly hiding himself in the mirror meant for customers to view themselves wearing this jewelry.

The event was definitely a great time, and if I met you there I’d love to connect on Twitter @JeremySCook. For that matter, if you have a creation that involves Tindie that you’d like to see featured here, please get in touch. You can also contact Tindie’s official Twitter account with any questions, comments, or concerns.

Limor Fried (aka ladyada) visiting with Jasmine and Brian at the Tindie Booth

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