Tindie

Tindie, is of course the premier marketplace for indie electronics, but don’t forget to peruse the Flea Market section too. From time to time garages and offices need to be cleared out and the best place to find a new home for your projects and parts is Tindie’s Flea Market.

Here are some interesting items available for sale as of the end of June. As always, this section isn’t subject to the same guarantee as Tindie’s normal listings, as this section functions as sort of an online garage sale:

Lock Pick Training Kit

If you’d like to learn how to pick locks, what better way than actually being able to see the inner workings while attempting this mechanical hack? To help with this pursuit, this training lock is clear, and comes with a set of picks.

LED Glasses

Sure, usually you wear glasses to protect your eyes from the sun, or correct your vision, but why does it have to be all about you? These RGB glasses allow you to program them to display light patterns for all the world to see!

SwitchiFy WiFi Home Automation Board

Home automation is great when you have your smartphone handy, but if you’re trying to integrate it with an existing 2-switch setup, things can get tricky. The SwitchiFy board, listed as “used,”allows you to still flip one of two switches to control lights or another appliance, and can take advantage of smartphone control when that’s available as well.

Trimmer Capacitor 10pF to 100pF

Trimmer capacitors are meant to calibrate equipment during manufacturing, analogous to the way a  potentiometer is a variable resistor. If that sounds fascinating, be sure to check them out in this listing.

These are just the tip of the iceberg, head over and see for yourself!

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When you first start programming with an Arduino or other development board, the “Hello World!” of that genera is to blink the onboard LED. You probably want to go further though, which can be difficult if you don’t have a drawer full of spare parts.

You could purchase some sort of starter kit, or on the other end of the spectrum, you can always just buy parts from various online outlets at extremely cheap prices with very slow shipping. Though taking weeks or more to arrive won’t satisfy your need for instant gratification, at least you’ll eventually build up quite an electronics collection. If you can figure out what to order.

Another option is the S4A board. This device fits on an Arduino Uno, leaving several I/O pins open, and includes buttons, potentiometers, LEDs, a buzzer, and accommodations for two servos. These components are already attached, so no soldering or breadboarding is involved, you simply plug it in and use as a test device or teaching tool.

On the other hand, if you’d test your I/O with only a bunch of LEDs and a breadboard, that can be fun as well:

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Alex Albino, of the Femtoduino Store, is one of the original sellers on Tindie, with his store officially listed as opening on November 26, 2012. During this time, he’s sold well over 300 of his custom boards, and I was glad to catch up to him to ask a few questions.

Albino, who works as a software and web developer, first got into electronics after his NES was fried in a thunderstorm in junior high, and he got to take it apart. Eventually his interests led him to the Arduino and Fabio Varesano’s work, and multiple hardware platforms over the years.

Albino’s store started with him asking Fabio Varesano if he could sell Femtoduino boards, which have the same outputs as an Arduino Uno in the size of one’s thumb. Since Varesano wasn’t interested in selling them himself, he generously gave Albino permission to run with this design. Albino then went to work assembling and selling these boards, and even made sure to give a portion of the money he made—though he didn’t have to—back to Varesano to promote his open source work.

Of course, these tiny Arduino clones are still for sale, but Albino sells several other items, including the FemtoBeacon wireless IMU (inertial measurement unit) sensor. He even notes his store theme as providing the smallest open source IMU sensors in the world. You can see one in the image above next to a U.S. dime—quite small indeed. He hopes to grow the Femtobeacon business into a full-time job in the future.

Naturally, Albino has bought from other Tindarians in the past, which he says is always fun. He also notes that, “If you sell anything on Tindie, make sure to package carefully, take decent photos, and include videos of stuff in action!” As such, here’s a video of the tiny Femtoduino in action:

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Every day you wake up, perhaps check your phone or other Internet connected device, and head out the door or into your home office to do whatever it is that keeps you busy during the day. This almost certainly involves some sort of communication and that constant passing of data wouldn’t be possible without switched packet communications.

This technology allows a network to allocate resources based on traffic needs, not tying up an entire data line for one connection, whether data is currently being transmitted or not. This is especially important for wireless communications, where there is a limited data spectrum that everyone has to share.

This then begs the question, how much data is flying around the air at any one time? If you’d like an answer in your specific location, this ESP8266-based device will tell you how many packets of data are sent over the WiFi channel that it’s monitoring. It does this using an ESP8266 module to intercept these transmissions, along with a small OLED screen, which displays a nice graph to show you peaks and troughs in the data usage of networks in range.

It’s a strange thing to think about all of this information literally passing through your body at any point during the day. Add to that the WAN channels that you won’t be monitoring at a certain time, along with other frequencies like FM or VHF, and it’s truly amazing to think about. Perhaps wearing a tinfoil hat isn’t the craziest idea anyone’s come up with, considering the invisible system that governs much of our lives constantly transmitting data through the air!

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Perhaps you’ve seen the incredibly successful Slow Dance Kickstater, which bills itself as “a frame that slows down time.” The frame works by causing an object, like a feather or part of a plant, to move very quickly using an electromagnet, then slows down the object’s perceived motion, using a carefully timed sequence of light pulses.

It’s an interesting principle, which has many other uses, such as checking a car’s timing and photography. Generally speaking, it’s the same principle that allows television and film to trick your eyes into thinking that a series of static images is actually moving.

So, since you’re reading Tindie’s blog, hopefully your next question is how do I do this? To answer that question, Tindarian “Jollifactory” outlined how he made one inside of an IKEA frame in this excellent Instructables article. He also mentions another similar build and set of instructions by author “cubic-print,” if you’d like a different take on things.

If you’d like a little help sourcing  your components for a build, Jollifactory has a kit available that includes the basic circuit board. Additionally, there’s an option to purchase frame mounting hardware and an electromagnet assembly if you need those as well.

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Perhaps you’ve heard the terms “low-pass,” “high-pass,” or “band-pass,” and like me realized it had something to do with the frequency fed to speakers, but never gave it much more thought. Check out the video below to see what these terms mean in practical terms:

As it just so happens, the device used in this excellent illustration is running on an Arduino board. In combination with the Audio Hacker Shield, an Arduino can be set up to do fun audio experiments like filter certain frequencies as shown here, as well as record and modify the playback speed of an audio source. It can also be used as a voice changer, MIDI device, a drum machine, and many other experiments depending how it’s set up.

A DJ Shield Deluxe, shown covering the Arduino and Hacker Shield, provides the fun knobs and buttons. As interesting as that looks modifying audio, it should be noted that this device can also be used as any other sort of Arduino input.

So if you want to start hacking audio with your Arduino, or simply illustrate different filtering techniques, this shield looks like a great place to start. You can find even more info on nootropic’s site.

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With a powerful processor, communication capabilities via WiFi, Bluetooth, or even longer range signals like cell modems, the Raspberry Pi is extremely well suited to remote environmental monitoring. For example, check out the video below from a remote water trough monitoring station described here, set up in 2015 with a Raspberry Pi to monitor a watering trough in Australia.

Though traveling to remote sites might provide a relaxing break for farmers while in transit, getting there can represent a large chunk of time that could be better used. Additionally, being able to catch water issues earlier is certainly better for animals, who otherwise might have to do without until the next visit.

One thing that makes a setup like this complicated, however, is reliably getting power to the ‘Pi. The Solar Pi Platter, pictured set up in the first image on this post, takes care of a lot of non-standard power details, allowing a Raspberry Pi to be powered via a Lithium-ion battery, charging said battery from solar panels or standard USB chargers, and importantly, a real-time clock to allow it to turn off to save energy as needed. Additionally, it features accommodations for analog inputs and PWM outputs, giving the ability for more versatile remote monitoring and control.

Or, as creator Dan Julio puts it, “[It’s] a versatile power board that can run Linux for $5 (and, now $10) more.” Check it out via the link above, or on Hackaday.io for even more info on the project.

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If you’re like me and many others that grew up in the 1980s, you’ve wanted your own arcade cabinet since nearly the first time you saw one. Sure, you could make the argument that modern consoles are much better than anything in that era, or that sitting on your couch is superior to standing up while pumping quarters into a Street Fighter II game, but there’s just something awesome about these systems that goes beyond pure functionality.

If you do decide to actually take the plunge and obtain a cabinet, there are lots of options out there, from building one from scratch out of MDF and electrical components, to refurbishing a used arcade machine, to simply buying a kit or ready-made device. If you’d like some inspiration, here are several awesome and unique builds on Make, including one that cleverly integrates a refrigerator.

There is, however, one problem with all of these machines: they take up a huge amount of space. They are also quite opaque, which isn’t a problem for most, but prevents you from seeing what’s going on inside. For those people, may I present the Tiny Arcade Clear DIY Kit. These little devices can easily fit between your thumb and index finger, and are made out of clear acrylic. It’s loaded with several classic arcade-style games, and you can add more games or even video via a micro SD card (that you’ll need to supply).

I got to see these at the World Maker Faire in New York last year, and to be honest, pictures don’t really do their diminutive size justice. It’s great to see something I’ve gotten to play with pop up on Tindie!

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It’s time to charge your phone or other device on a USB receptacle you don’t own, so you would rather not expose the data lines as well. DIY options vary from cutting and disconnecting the appropriate cable (I’d suggest heat shrink) to literally taping over the data contacts. Though the tape method might not be the most durable, it’s quite clever, and would work well in a pinch.

For this particular use there are commercially available USB data blocker options at market. But this is the first time I’ve seen one that has the ability to selectively switch all four of the USB lines.

The USB-Helper can switch off the data, power, and ground pins individually. For hardware developers this can come in quite handy for testing as you go. Want to share data and common ground but not the power rail? No problem. Need to test what happens if there’s a break in just one of the data lines? This dongle is for you. It’s available assembled, and even has an optional 3D-printed case.

For help with other USB hacking/modifications, Tindie has quite a few USB breakout boards, which I outline here. I’ve also gone over some of the more “Exotic” breakouts in a separate post if you need something even more interesting.

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When building a mobile robot, one of the easiest ways to allow it to roam about is to use a wheel on either side in a sort of tank-like configuration. An example from Macerobotics is shown in the image above. On the other hand, it’s a good idea to consider other options. Tank treads, Mecanum, and omni-wheels are all viable options.

Omni Wheels

One clever wheel option, which according to Wikipedia was patented in 1919, is the omni wheel. These devices, which have smaller rollers attached at 90° to the larger wheel’s axis of rotation can be extremely useful because of their ability to move items in two directions. In fact, they can often be seen transporting boxes in factories. Importantly for this discussion though, these wheels can be combined in the angular orientation seen above to allow a robot to slide and turn in any direction.

Mecanum Wheel

Another interesting option is Mechanum wheels. Instead of secondary rollers being attached at 90° to the main wheel, they’re attached at 45°. This means that a vehicle can be set up with the wheels in an orientation similar to a traditional car; when all the wheels move forward, the robot also moves forward. The trick comes when the wheels are rotated in different directions, allowing it to turn and slide in a similar manner to how omni wheels work.

So which type of wheel or drive system is the right choice for your next project? Of course it all depends on the situation, but its at least a good idea to keep different options in mind. Grab some more inspiration for you upcoming builds by browsing the Robot and Drone parts on Tindie!

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