Tindie

Depending on your experience with programming and electronics, you may have run into a situation where if you flip a switch, your device somehow thinks that you’ve switched the input multiple times.

This may seem strange, but when metal contacts hit each other, they tend to literally bounce on and off of each other for a short amount of time. This “bouncing time” can reportedly last between 10 and 300 microseconds, which as humans, we certainly don’t notice. You might consider that 300 microseconds (µs), expressed differently is 3 ten-thousandths of a second. It’s a fascinating topic and if you want to dive in you should check out the recent Spark Gap podcast episode on button types and debounce.

Though short to us, to modern computers and microcontrollers, this can be an eternity, allowing them to process many instructions. Though this speed presents a problem, it also presents solutions. As shown in this Arduino example, you can simply code things to wait until the state change has been experienced for a certain amount of time before recognizing it as such.

The disadvantage of this technique is that it requires extra code, making things less streamlined than they could be, and if you’re working with hardware-based logic, you’d need to use a different technique. There are solutions of course, including this NE555-based kit by Theosauro. It uses the button to trigger a 555 timer (that’s the NE555 chip) to output a very clean logic signal you just can’t get from a button alone.

So the next time your code is acting strange, consider adding a debounce function, either through hardware or software!

Keep Reading ›

As you get more and more into the world of making electronics, you may find that you need to solder components onto circuit boards using a reflow soldering process (short video of it below). Though this may seem like an exotic method used by large manufactures, the good news is that some of these machines are quite accessible. In fact, a quick search will likely pull up reflow ovens for well under $1000.

On the other hand, the process of heating up the solder paste in a controlled manner isn’t really that exotic of an endeavor, and, if you happen to have an old toaster oven lying around, you can convert this into a reflow device. You can see an example of how this can be done on this instructables page, though I woudn’t be too keen on using it for toast afterwards.

If you’d like a little help getting started on your toaster oven project, or if you’d like a nice color interface, you might check out the X-toaster toaster oven reflow controller kit. The device allows you to enhance your oven for general use without internally modifying the oven, and it can be programmed without using a PC. More information on how the device can be set up is found on their website.

Keep Reading ›

Ken.Do’s hexapod robotics platform

Building walking robots is difficult. In fact, my first robot, a 3-servo hexapod that I named “PegLeg,” only really worked well after I remade it using machine tools, such as a milling machine and lathe.

Since then, I’ve made several other walking ‘bots, and/or remote vehicles depending on how you want to classify them, and it generally seems that getting the mechanics to work well together is the most difficult part. Then again, I’m a mechanical engineer by training, so perhaps it’s simply what I put my effort into, finally being satisfied with the control system working “well enough.”

If, on the other hand, your “thing” is programming and you would rather not fool with getting the mechanical bits, there are other options available. One such robot that caught my eye was this 20″ hexapod robot that can operate as either an 18 degree-of-freedom (DOF) walker, or in 12 DOF mode.

Though the robot comes with “no guarantee of functionality,” it does look quite fetching in red, and I can only imagine how long it would take to design and/or print a frame like this from scratch. If you just want to get your robot working, then something like this could be a good option.

Keep Reading ›

Although makers/hackers/DIY enthusiasts have been around since man invented the wheel — or perhaps even before — it seems that a big part of what’s fueled the current crop of home invention has been inexpensive development boards like those developed by Arduino. In fact, if you’re going to make a simple robot or automatic device, Arduino products, specifically the Arduino Uno acts as a sort of de facto standard.

The great thing is that this means that there is an incredible pool of resources to pull from, including learning materials and expansion shields. This works really well for simple applications, but there are other options available that have more power and/or communications capabilities than what the Uno offers. One exciting possibility involves development boards based around the ESP8266 and ESP32 WiFi modules. Not only do these modules have WiFi capabilities, they can be very small, and feature a powerful ARM processor.

X-32 module by itself

If you’d like to get your feet wet with this system, this X-Project Starter kit features boards with an ESP32, as well as one with the ESP8266-based WROOM-02. Along with these boards, the kit includes a series of “X-size” shields, so you’ll have components to play with right off the bat.

Keep Reading ›

If the golden age of arcade video games took place in the early 1980s, then perhaps today we are living in the golden age of DIY gaming systems. Many older computers can be used to run these games, and small single-board computers such as the Raspberry Pi have enough power to emulate arcade games of old for a price under $50.

One challenge though, unless you want to use a keyboard or a standard USB controller, is getting the physical inputs from arcade button to control your emulation software. You could (as I have) attempt to take apart a keyboard and wire the buttons into individual keys. From experience, this does work, but is quite difficult soldering-wise, and multiple button presses can get hairy.

There are also USB-based solutions that allow you to plug wires in which translate data to a computer as an interface device. This works much better, and I wish I’d done some research before destroying a wireless keyboard!

On the other hand, if your platform is a Raspberry Pi, here’s a solution that attaches to it as a HAT, the aptly named “RetroHAT”. The device helps GPIO inputs into keyboard presses, which should be quite useful for getting a cab’ up and running!

Keep Reading ›

Today, using the Internet means keeping track of passwords. This can take many forms, from simply using the same password for all sites you visit (very bad), making up “random” passwords for each site you need to log into (better), or perhaps using some sort of strong password generator and storage system (perhaps best, but with a big asterisk of “what if the system gets hacked?”).

Another intriguing method would involve some sort of routine based on, say, books on a certain shelf, or even a mechanical generator like the one featured here. One of the huge advantages of a system like that is it’s offline, so it couldn’t (practically speaking) be hacked. On the other hand, this type of system can be inconvenient, or perhaps not portable.

Attempting to fill this void is the Mooltipass Mini. This device, which has been a project since 2013 (my blurb on the original), stores passwords on a smartcard, which can either generate passwords for you or import your passwords as needed. To a computer or smartphone, it then acts as an external keyboard, entering your data as needed. You can see more about it in the Tindie link above, or on its recently concluded and wildly successful Kickstarter campaign.

Available in several colors

As you might suspect, this device has also been quite successful on Tindie, selling 100 units in the three days following its debut. In fact, according to Mathieu Stephan, who has driven this project from the beginning, they’ve sold thousands of these devices in total, while sticking to their planned Kickstarter schedule for fulfillment.

So with so many of these having been sold, if you see someone else using one in the wild, you’ll know it’s not just an exotic (and beautifully-metallic) MP3 player. Perhaps say “hello,” rather than gawking too much, as the person using it is obviously at least somewhat concerned about security!

Keep Reading ›

Consumer-level 3D printing has certainly revolutionized what can be made at home. Although the materials generally used wouldn’t be suitable for, say, structural automotive parts, the shapes that one can easily create with one of these printers would be very difficult to make using traditional machining methods. Sure, if you happen to have a 5-axis machining center in your garage, you could duplicate many of these results, but the fact that many of these machines cost in the hundreds of dollars rather than many tens or even hundreds of thousands for a CNC machining “equivalent” is really an accomplishment.

On the other hand, these machines, especially the least-expensive of them, require some fiddling to get them working. You’ll also need an external computer to prepare your models for printing, and if you’d like to duplicate a physical object via 3D scanning, that’s an entirely different machine/process.

For a different take on things, the Zeus Printer/Editor/3D scanner works as a 3D printer, but also has a 3D scanner built-in as well as a 7-inch touchscreen and editing capabilities. So in theory, you don’t even need a computer to work with this device. The first video below shows an overview of the device, while the second shows a demonstration of it working as a “simple” 3D copy machine.

Keep Reading ›

There are people of diverse backgrounds selling on Tindie, but as far as I know, Jakub Polonský is the only one here with a PhD in electrochemistry. Though this gave him a good background in testing of electronic quantities for electrochemical systems, as far as designing electronics, he’s self taught. He graduated in 2012, but started with Arduino boards in 2010, allowing him to use this versatile tool for research purposes.

Polonský has been selling here since June of 2014, and offers test and measurement items that he’s made. I asked him to talk about the best parts of selling on Tindie.

Tindie is unique. A place that contains so much creativity and so many diverse things from people who actually designed them. It is so much different from the mass-produced generic stuff that you can buy on an auction site that begins with an “e” and ends with a “Bay”. The tight connection between the designer and customer is what I really like. I can talk with customers and if they want some feature or have a problem, I can directly solve it because I am the one who can add that feature and I know the most about my products. The conversations are very relaxed and friendly and often turn into a nice chat way past the initial issue.

As far as the worst, he notes that:

I am still not convinced that taking out pre-orders was a good idea… but I learned how to manage inventory so I am rarely out of stock.

Jakub believes the way you present information about products makes all the difference.

From what I have experienced, buyers like a good detailed documentation that can be understood even if they don’t possess such a deep knowledge of the item as the designer/seller does. So make the documentation thorough but readable. Test it on your friends/wife/grandpa 🙂

What could be considered the flagship product of his “Kaktus” store, the “MightyWatt” Arduino-controlled electronic load, was born out of his research.

I was involved in PEM fuel cell research and we had a commercial electronic load but its software was so-so and it was crashing frequently so I thought “hey, I can do this better and cheaper”. So I did and we ended up using six of MightyWatts, which costed less than one commercial load. The original application was thus PEM fuel cell testing but from my customers I know it’s being used in three main areas: solar cells, batteries and power supplies.

The device, which is now on its third revision, uses a FET as a variable resistor to maintain either a constant current load or a constant current drop. If you’re wondering, as I did, if a second resistor in series is needed to maintain the voltage drop, this is not the case:

It does not need any extra physical resistor. In the case of power supplies, they will switch to current-limited mode and in the case of batteries and fuel cells, their internal resistance will act as the second resistor so they have it “built-in.”

Pretty neat. So now you know that if you can produce something that “wastes” power in an extremely controlled and scientific manner, there’s actually a market for it. Polonský notes that, “I am really grateful that Tindie is there. I probably wouldn’t be selling MightyWatt at all if it weren’t for Tindie.”

Keep Reading ›

If you started using computers when CD-ROM drives seemed to have an amazing amount of space at around 650MB each, the fact that you can store many Gigabytes of data on a micro SD card the size of a rather small thumbnail seems amazing. At least it does to me. Though I grew up in an era when you could misplace a disk, it wasn’t going go be lost in the carpet, or even vacuumed up without some loud mechanical protest.

5 Megabytes in the 1950s; via reddit

On the other hand, even by that time things had progressed significantly, as this photo of a 5MB hard drive being loaded onto a plane shows.

So how do you actually organize these tiny devices? Cloud data storage is a great alternative for many of purposes, but if you need to keep data on portable media, you’ll need somewhere to physically store them. A baggie or jewelry box could work, but here’s something actually made for that purpose.

The picture at the top of this post is like one-organizer-to-rule-them-all and will put an end to digging through drawers looking for that microSD or low-provile thumb drive. It can hold 8 standard SD cards, 15 microSD cards, and 10 USB flash drives. As they are 3D-printed, you can customize the number of slots for each one as needed.

It looks like a clever idea. On the other hand, I wouldn’t attempt to clean it with a vacuum cleaner!

Keep Reading ›

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.

Keep Reading ›