Day: May 12, 2016

Hackaday Prize Entry: ForEx Display Is A Well Executed Hack

May 12, 2016 by 16 Comments

[Stefan] works in a place where knowing the exact state of the foreign-exchange market is important to the money making schemes of the operation. Checking an app or a website was too slow and broke him out of his workflow. OS desktop widgets have more or less departed this earth for the moment. The only solution then, was to build a widget for his actual desk.

The brains of the device is a ESP8266 board, some peripherals and a small backlit TFT display. The device can run off battery or from a wall wart. [Stefan] even added some nice features not typically found in hacks like this, such as a photocell that detects the light level and dims the screen accordingly.

The software uses an interesting approach to get the latest times and timezones. Rather than use a chart or service made for the task, he uses an open weather API to do the task. Pretty clever.

The case is 3D printed and sanded. To get the nice finish shown in the picture [Stefan] spray-painted the case afterwards. All put together the device looks great and gives him the desktop widget he desired.

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Digitize Your Graphs With WebPlotDigitizer

May 12, 2016 by 11 Comments

Have you ever had to write a bit of code to interpret a non-linear analog reading as picked up by an ADC? When all you have to work with for your transfer function is a graph in a semiconductor datasheet that was probably written thirty years ago and prints out the size of a postage stamp, that’s a rather annoying task. Wouldn’t it be nice if you had access to the numbers behind the graph!

You can’t knock on the office door of the engineer who created it back in the ’80s, he’s probably  in retirement and playing golf or growing prize petunias by now. But you can digitize the graph to get yourself a lot closer to the action, and to help you in your quest there’s a handy online tool.

2N3904-current-gain
2N3904 current gain

WebPlotDigitizer is not new, it’s been around for quite a few years now. But it’s still worth talking about, because it’s one of those tools to keep in reserve. If you’ve ever needed it, you’ll know what we mean.

So how does it work? Load an image with a graph in it, select some points on the X and Y axis, roughly trace the curve with a marker tool, and set it in motion. Let’s give it a go. We’re going to try digitizing the current gain plot from the 2N3904 datasheet (PDF) that we examined a few days ago.

data-points
Data points!

So, open the WebPlotDigitizer app, load the graph image captured from the sheet as a JPEG. It asks what type of graph you’ve loaded, in this case a 2D X-Y plot. It asks you to identify four known points on the axes and supply their values. You also tell it if the axes are logarithmic at this point. Select “Automatic mode” on the right hand side, then click “Pen” and mark the graph trace, then select the colour of the trace. Click the “Run” button, and your data points appear. Hit the “View data” button, and there you have it. A few rogue points to remove perhaps, but it does a pretty good job.

If WebPlotDigitizer has engaged your interest, you’ll be pleased to know that it’s open-source, and you can find all its code on GitHub. There is also a handy video tutorial which you can see below the break. Continue reading “Digitize Your Graphs With WebPlotDigitizer” →

Reading An IR Thermometer The Hard Way

May 12, 2016 by 25 Comments

[Derryn Harvie] from the MakeHackVoid maker space hacked a $10 IR Thermometer and made it talk USB. Sounds easy? Read on.

He opened it up in the hope of finding, and tapping into, a serial bus. But he couldn’t find one, and the main controller was a COB blob – hidden under unmarked black epoxy. Normally this is a dead-end.  (We’ve seen some interesting approaches to decapping epoxy blobs, and even ICs with lasers.)

But [Derryn] went his own way – intercepting the data going from the micro-controller to the LCD display, and reverse engineering it using another microcontroller. He scraped off the solder mask over the tracks leading to the LCD display, and used an oscilloscope to identify the common drive lines. He then used a function generator to excite each of the LCD common lines and the segments lines to build a complete matrix identifying all the combinations that drove the segments. With all the information decoded, wires were soldered so he could hook up an Arduino, and the cut tracks repaired.

Since the LCD was a multiplexed display, the bias voltages were at four levels. Luckily, he could extract most of the LCD information by reading just eight of the segment drive lines, using up all of the analog inputs on the Arduino. Perhaps a different microcontroller with more ADC inputs would have allowed him to display more LCD functions. Well, he can always upgrade his upgrade later. If you have a similar hack to implement, then [Derryn]’s code could be useful to get started.

Thanks, [csirac2] for sending us this tip from MakeHackVoid.

Robo Face Speaks

May 12, 2016 by 3 Comments

If you are doing a senior design project in engineering school, it takes some guts to make a robotic duplicate of the school’s president. He or she might be flattered, or completely offended. Us? We laughed out loud. Check out the video below. Spoiler: the nose/moustache wiggle at the end kills us every time.

The project uses a variety of parts including a plastic mask, an Erector set, and the obligatory Arduino with an MP3 shield. There are many articulated parts including eyes, nose, mouth, and wiggly moustache. The face uses RC servos, although [gtoombs] says he’d use stepper motors next time for smoother motion.

Continue reading “Robo Face Speaks” →

To See Within: Making Medical X-rays

May 12, 2016 by 47 Comments

I was a bit of a lost soul after high school.  I dabbled with electrical engineering for a semester but decided that it wasn’t for me – what I wouldn’t give for a do-over on that one. In my search for a way to make money, I stumbled upon radiologic technology – learning how to take X-rays. I figured it was a good way to combine my interests in medicine, electronics, and photography, so after a two-year course of study I got my Associates Degree, passed my boards, and earned the right to put “R.T.(R) (ARRT)” after my name.

That was about as far as that career went. There are certain realities of being in the health care business, and chief among them is that you really have to like dealing with the patients. I found that I liked the technology much more than the people, so I quickly moved on to bigger and better things. But the love of the technology never went away, so I thought I’d take a look at exactly what it takes to produce medical X-rays, and see how it’s changed from my time in the Radiology Department.

Continue reading “To See Within: Making Medical X-rays” →

That’s No Moon – That’s A Bamboo Death Star

May 12, 2016 by 25 Comments

At first glance, [Frank Howarth]’s turned bamboo Death Star seems like a straight woodworking project. No Arduino controlled lights, no Raspberry Pi for audio clips of an X-wing attack or escaping TIE fighter. In other words: where’s the hack?

It’s a freaking bamboo Death Star!

If that’s not enough for you, check out the pattern on the surface of the finished model. That’s not painted on – those are the layers of the laminated bamboo lumber used to create the rings [Frank] used to form the structure. After lots of turning, sanding and polishing, the characteristic vascular bundles of the bamboo create light and dark panels for a convincing effect of the Death Star’s surface detail. And although we like the natural finish, we can imagine a darker stain might have really made the details pop and made for an effect closer to the original.

Still not hackish enough? Then feast your eyes on [Frank]’s shop. It’s a cavernous space with high ceilings, tons of natural light, and seemingly every woodworking machine known to man. While the lathe and tablesaw do a lot of the work for this build, the drool-worthy CNC router sees important duty in the creation of the multiple jigs needed for the build, and for making the cutout for the superlaser, in what must have been a tense moment.

Bamboo is an incredible material, whether for fun builds like this or for more structural uses, like a bamboo bike. All this bamboo goodness puts us in the mood to call on [Gerrit Coetzee] for a new installment on his “Materials You Should Know” series.

Continue reading “That’s No Moon – That’s A Bamboo Death Star” →

Path To Craftsmanship: Safety, Cleanliness, And Documentation As Habits

May 12, 2016 by 49 Comments

When I started boxing classes I was told, at my level, I could do just as much good for my form by doing core exercises such as crunches, running, push-ups, and pull-ups for a month as I could by doing the class. I consder habits like safety, cleanliness, and documentation to be habits that influence the quality of hacks much the same way. They’re not really related, and the work can get done without them, but their implementation alone improves the quality of everything you do at the workbench.

The best mechanic I’ve ever met had a well-organized shop. All of his employees wore nitrile gloves when they worked on engines to protect their hands from the chemicals inside. They used ear protection and safety glasses. His rates were low, and the car was always repaired fast. I never had to go back for the same repair twice. He knew exactly what repairs were done, and even kept the parts removed from my vehicle to show me if I desired. I got some of the most fantastic explanations of why parts failed from him. Two blocks down the street was a shop which was unorganized and had double rates. The employees were always sitting on the waiting chairs in the lounge. It took one trip there to never return.

Continue reading “Path To Craftsmanship: Safety, Cleanliness, And Documentation As Habits” →