New Part Day: Indoor Location Systems

June 17, 2015 by 86 Comments

GPS is an enabling technology that does far more than the designers ever dreamed. If you want a quadcopter to fly to a waypoint, GPS does that. If you want directions on your phone, GPS does that. No one in the 70s or 80s could have dreamed this would be possible.

GPS, however, doesn’t work too well indoors. This is a problem, because we really don’t know what is possible if we can track an object to within 10cm indoors. Now there’s a module that does just that. It’s the decaWave DWM1000.

This module uses an 802.15 radio to track objects to within just a few centimeters of precision. It does this by sending time stamps to and from a set of base stations, or ‘anchors’. The module is also a small, and relatively high bandwidth (110kbps) radio for sensors and Internet of Things things makes it a very interesting part.

Some of the potential for this module is obvious: inventory management, and finding the remote and/or car keys. Like a lot of new technology, the most interesting applications are the ones no one has thought of yet. There are undoubtedly a lot of applications of this tech; just about every ball used in sports is bigger than 10cm, and if ESPN ever wanted even more cool visuals, just put one inside.

If you’d like to try out this module, decaWave has an eval kit available through distributors for about $600. Somehow, there’s also a Kickstarter for a board that uses the same module, Arduino compatible, of course.

Thanks [Roy] for the tip.

An Introduction To Zener Diodes

June 17, 2015 by 21 Comments

[Afroman] is back again with another great tutorial video on the basics of electronics. This time it’s zener diodes.

Page three or four of every ‘beginners guide to electronics’ covers a diode as, “a component that only allows current to flow in one direction.” This is true; a diode only allows current to flow in one direction. However, like any depth of knowledge, the dialectic of diodes quickly turns to a series of, ‘but..’ and ‘however…’ statements.

A zener diode is like a normal silicon diode, where a forward biased diode will pass current with a ~1 volt drop. When a zener diode is reversed biased, there’s a different voltage drop, annotated as Vz on the datasheet. When reversed biased, current cannot flow across the diode unless the voltage is above Vz. This is what makes zeners useful for a bunch of applications.

[Afroman] goes over a few of the most useful applications of zeners, including a diode clamping circuit. This circuit will clamp the voltage to a maximum of Vz, helpful when you’re feeding a signal into an analog input. This voltage clamping circuit can be used in some interesting applications. If you feed a sine wave or other signal though the circuit, you can clip the signal.

Zeners can also be used as a very crude, low current, low accuracy power supply. If you’re looking for a voltage regulator for a microcontroller that’s impossibly easy and you’re all out of 7805s, pick up a zener. It’s not the basis of a good power supply, but it does work.

Animated GIFs On A Graphing Calculator

June 17, 2015 by 26 Comments

The TI-84 Plus graphing calculator has a Z80 processor, 128 kilobytes of RAM, and a 96×64 resolution grayscale LCD. You might think a machine so lean would be incapable of playing video. You would be right. Animated GIFs, on the other hand, it can handle and [searx] is here to tell you how.

Before assembling his movie, [searx] first needed to grab some video and convert it to something the TI-84 could display. For this, he shot a video and used Premiere Pro to reduce the resolution to 95 by 63 pixels. These frames were saved as BMPs, converted to monochrome, renamed to pic0 through pic9, and uploaded to the calculator’s RAM.

To display the animated GIF, [searx] wrote a small program to cycle through the images one at a time. This program, like the images themselves, were uploaded to the calculator over the USB connector. Playing these animated GIFs is as simple as calling the program, telling it how fast to display the images, and standing back and watching a short flip-book animation on a calculator.

Astronaut Or Astronot: Vote For The Hackaday Prize!

June 17, 2015 by 14 Comments

Just in case we haven’t hammered it into your skull quite yet, we’re having a little contest over on Hackaday.io. It’s The Hackaday Prize, where everyone on Hackaday.io is invited to build something cool for the chance of winning a trip to space and hundreds of other prizes.

We know not everyone has the desire, skills, or the time to build a project, but that doesn’t mean you can’t still contribute. We’re holding a community voting round right now. Each week, we have a new round of community voting with a new theme. This week, we’re asking the Hackaday.io community to select the project that is most likely to be widely used. What do you have to do to participate? Just go over to the voting page, and choose between two projects our especially fair voting algorithm pulled from current Hackaday Prize entries. Pick the project that best meets the theme of the week.

Why would anyone want to do this? This Friday, I’ll be taking a look at everyone on Hackaday.io, pulling a number out of a hat, and if that person voted in the current round of voting, they win a thousand dollar gift card to the Hackaday store. We’re also giving away Hackaday t-shirts to random people who have voted each week.

The only losing move is not to play, so go over to the voting page and pick the projects that best meet the theme, “most likely to be widely used.”

Rise Of Hardware: A PCH Hackathon

June 17, 2015 by 1 Comment

Over the weekend, I had the pleasure of helping out at the KW Hackathon in Waterloo, Ontario, sponsored by PCH Hardware, who hosts hackathons and meetups around the world to help inspire invention and entrepreneurship. This was the sixth hardware based hackathon they have hosted.

When they host a hackathon, they gather local sponsors and provide the tools and resources for the entrants to actually develop a working prototype in less than 54 hours, that they then can pitch to a panel of judges to win some awesome prizes. Did we mention it’s free to register? The next one is in London, England.

Personally, I provided some mentorship in product design and development, but more importantly, I opened up the use of my giant laser cutter to help the teams create real prototypes, and learn more about rapid prototyping using a laser cutter. Everyone wanted to 3D print their prototypes at first — but there was a limited number of printers available, and long wait times. We introduced them to sites like www.makercase.com, a site that will generate laser cutter plans for enclosures that you specify the dimensions of, and of course, the ability to search google for “laser cut arduino case” to find pre-designed laser designs for electronics.

Some teams more experienced in CAD got creative and made cool decahedrons which actually helped create a working prototype the way they envisioned it on paper.

PCH-Hackathon-for-Communitech-Day-2-496

In addition to the main event, they hosted keynote speakers and workshops to help take teams ideas even further — we think Communitech (the hosting venue) really summed up the purpose of having hackathons nicely:

“Useful stuff does really emerge from hackathons: some realized ideas, but more importantly, new human hacker connections and a deeper sense of capability and our capacity to create beyond the software realm.”

Overall, the event was fantastic, and it makes us wish there were more like it. You could feel the buzz of excitement in the room when creative people got together and started designing and making things. Oh and the free food was pretty awesome too — especially for students.

For more information about the event, check out the news piece by [Darin White] for Communitech News.

Microcassette Recorders Become A Tape Delay

June 17, 2015 by 25 Comments

Long before audio engineers had fancy digital delays, or even crappy analog delays, there were tape delays. Running a tape around in a loop with a record and play head is the basis of the Echoplex and Space Echo, and both of these machines are incredible pieces of engineering.

Microcassette recorders are not, in general, incredible pieces of engineering. They do, however, have a strip of magnetic tape, a record head, and a play head. Put two of them together, and you can build your own tape delay.

The basic principle of a tape delay is simple enough – just run a loop of tape round in a circle, through a record and playback head, record some audio, and send the output to an amplifier. In practice, it’s not that simple. [dogenigt] had to manufacture his own tape loop from microcassettes, a process that took far too long and was far too finicky.

For a control circuit, [dogenigt] is using four audio pots and one linear pot for speed control. The audio pots are responsible for input gain, feedback, the amplitude of the clean signal, and the output of the signal after it’s been run through the delay.

Apart from being one of those builds that’s very dependent on the mechanical skill of the builder, it’s a pretty simple delay unit, with all the electronics already designed for a stripboard layout. You can hear an example of what it sounds like below.

Continue reading “Microcassette Recorders Become A Tape Delay” →

It’s A Sega It’s A Nintendo! It’s… Unique!

June 17, 2015 by 23 Comments

Before the days of the RetroPie project, video game clones were all the rage. Early video game systems were relatively easy to duplicate and, as a result, many third-party consoles that could play official games were fairly common. [19RSN007] was recently handed one of these clones, and he took some pretty great strides to get this device working again.

The device in question looks like a Sega Genesis, at least until you look closely. The cartridge slot isn’t quite right and the buttons are also a little bit amiss. It turns out this is a Famicom (NES) clone that just looks like a Sega… and it’s in a terrible state. After a little bit of cleaning, the device still wasn’t producing any good video, and a closer inspection revealed that the NOAC (NES-on-a-Chip) wasn’t working.

Luckily, [19RSN007] had a spare chip and was able to swap it out. The fun didn’t stop there though, as he had to go about reverse-engineering this chip pin-by-pin until he got everything sorted out. His work has paid off though, and now he has a video game system that will thoroughly confuse anyone who happens to glance at it. He’s done a few other clone repairs as well which are worth checking out, and if you need to make your own NES cartridges as well, we’ve got you covered there, too.