Hacklet 37 – Nixie Projects

Nothing quite beats the warm glow of a tube. What better way to enjoy that glow than to use it to read numbers? Nixie tubes were created by Haydu Brothers Laboratories, and popularized by Burroughs Corp in 1955. The name comes from NIX I – or “Numeric Indicator eXperimental No. 1″. By the mid 1970’s, seven segment LED’s were becoming popular and low-cost alternatives to Nixies, but they didn’t have the same appeal. Nixie tubes were manufactured all the way into the 1990’s. There’s just something about that tube glow that hackers, makers, and humans in general love. This week’s Hacklet highlights the best Nixie (and Nixie inspired) projects on Hackaday.io!

temperatureDisplayWe start with [Sascha Grant] and Nixie Temperature Display. [Sascha] mixed an Arduino, a Dallas DS18B20 Temperature sensor, and three IN-12A Nixie tubes to create a simple three digit temperature display. We really love the understated laser-cut black acrylic case. An Arduino Pro Micro reads the Dallas 1-wire sensor and converts the temperature to BCD. High voltage duties are handled by a modular HV power supply which bumps 9V up to the required 170V.  Controlling the Nixie tubes themselves are the classic K155ID1 BCD to decimal converter chips – a favorite for clock builders.


driverNext up is [Christoph] with Reading Datasheets and Driving Nixie Tubes. Chips like the K155ID1, and the 74141 make driving Nixie tubes easy. They convert Binary Coded Decimal (BCD) to discrete outputs to drive the cathodes of the Nixie. More importantly, the output drivers of this chip are designed to handle the high voltages involved in driving Nixie tubes. These chips aren’t manufactured anymore though, and are becoming rare. [Christoph] used more common parts. His final drive transistor is a MPSA42 high voltage NPN unit. Driving the MPSA42’s is a 74HC595 style shift register. [Christoph] used a somewhat exotic Texas Instruments TPIC6B595 with FET outputs, but any shift register should work here. The project runs on a Stellaris Launchpad, so it should be Arduino compatible code.

fixietube[Davedarko] has the fixietube clock. Fixietube isn’t exactly a Nixie. It’s an LED based display inspired by Nixie tubes. Modern amber LEDs aren’t quite the same as classic Nixies, but they get pretty darn close. [Dave] designed a PCB with a 3×5 matrix of LEDs to display digits. A few blue LEDs add a bit of ambient light. The LEDs are driven with a 74HC595 shift register. The entire assembly mounts inside a tiny glass jam jar, giving it the effect of being a vacuum tube. The results speak for themselves – fixietubes certainly aren’t Nixies, but they look pretty darn good. Add a nice 3D printed case, and you’ve got a great project which is safe for anyone to build.

openNixieFinally, we have [Johnny.drazzi] with his Open Nixie Clock Display. [Johnny] has been working on Open Nixie for a few years. The goal is to create a Nixie based clock display which can be driven over the SPI bus. So far, [Johnny] has 6 Russian IN-12 tubes glowing with the help of the ubiquitous K155ID1 BCD to decimal converter. The colons of the clock are created with two INS-1 neon indicators. [Johnny] spends a lot of time analyzing the characteristics of a Nixie tube – including the strike voltage, and steady state current. If you’re interested in building a Nixie circuit yourself, his research is well worth a read!

Not satisfied? Want more Nixie goodness? Check out our Nixie tube project list!

That’s about all the time we have for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Origami Busts a Move with Dancing Paper

Origami cranes are cool, but do you know what’s cooler? Origami cranes dancing to the beat. That’s the challenge [Basami Sentaku] took on when he created Dancing Paper (YouTube link). You might remember [Basami] from his 8 bit harmonica hack. In Dancing Paper, paper cranes seem to dance all on their own – even performing some crazy spinning moves. Of course, the “magic” is due to some carefully written code, and magnets, lots of magnets.

Using magnets to move objects from below isn’t a new concept. Many of us have seen the “ice skating pond” Christmas decoration which uses the same effect. Unlike the skating pond,Dancing Paper has moving parts (other than the cranes themselves). Under the plastic surface are a series of individually controlled electromagnets. Each of the supporting dancers has a line of four magnets, while the featured dancer in the center has a 5×5 matrix. The 41 electromagnets were wound around bolts with the help of a Tamiya motor and gearbox.

The actual dance moves are controlled by C code which appears to be running on an Atmel microcontroller. Of course a microcontroller wouldn’t be able to drive those big coils, so some beefy TO-220 case transistors were employed to switch the loads. The cranes themselves needed a bit of modification as well. Thin pieces of wire travel from the neodymium magnets on their feet up to the body of the crane. The wire provides just enough support to keep the paper from collapsing, while still being flexible enough to boogie down.

Click past the break to see Dancing Paper in action!

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Beating Super Hexagon with OpenCV and DLL Injection

Every few months a game comes along which is so addictive, players can’t seem to put it down – no matter how frustrating it may get. Last year one of those games was Super Hexagon. After fighting his way through several levels, [Val] decided that designing a bot to beat the game would be more efficient than doing it himself. Having played a few rounds of Super Hexagon ourselves, we can’t fault him on that front!

At its core, Super Hexagon is a simple game. Walls move from the screen edges toward a ship located near the center of the screen. The player uses the arrow keys to “orbit” the ship around a central shape. Avoid getting crushed by the walls, and you’re golden. However, the entire game board is constantly spinning, expanding, contracting, flashing, and generally doing things to disorient the player while ever more complex wall patterns move in to kill you. In short, Super Hexagaon makes Touhou bullet hell games look like a cakewalk.

The first step in beating the game is to capture the screen. [Val] tried Fraps and VLC, but lags of 2 seconds or more were not going to work. Then [Val] turned to DLL Injection. Super Hexagon calls the OpenGL function glutSwapBuffers() to implement double buffering. Every frame of the game is rendered in the background. Once rendering is complete glutSwapBuffers() is called to swap the buffers, and the process starts over again. [Val] changed the game code such that his own frame capture function would be called instead of glutSwapBuffers(). Once he was done capturing the game’s video buffer, [Val] then called the real glutSwapBuffers() function. It worked perfectly.

Now that he had an image, [Val] used OpenCV to process it. Although game is graphically very noisy, there are only a few colors used at any one time. It didn’t take much work to come up with an algorithm which would create a binary image of the walls and the ship itself.

step5[Val] cast rays from the center of each wall through the center of the screen. The ray which was longest before intersecting another wall would be the best escape route. This simple solution worked, but only for about 40 seconds. At that point, Super Hexagon would start throwing more complex patterns, and the AI would fail. The final solution was to create an accessibility condition which also took into account how much space was available between the various approaching walls. This new version of the AI was able to beat the game.

So was this a more efficient method than grinding through Super Hexagon manually? Since [Val] now knows all about DLL injection and OpenCV, we sure think it was!

Click past the break to see the [Val’s] bot in action!

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Hacklet 36 – Oscilloscope Projects

Oscilloscopes are one of the most often used tools of the engineer, hacker, or maker. Voltmeters can do a lot, but when you really need to get a good look at a signal, a good scope is invaluable. This week’s hacklet is triggered by the rising slope of some of the best Oscilloscope projects on Hackaday.io!

rigol500We start with [DainBramage’s] recent project Stretching the Limits of a Rigol DS-1102E Scope. The new Rigol ds1054z may be getting all the press lately, but the older DS-1102E (100 MHz) model is still a very capable scope. [DainBramage] broke out his vintage Singer CSM-1 service monitor to generate frequencies all the way up to 500 MHz. The Rigol did admirably well, detecting a sine wave all the way up to 500 MHz. This is in part due to the scope’s 1 gigasample-per-second sampling rate. Once things got beyond the specified limit of 100 MHz though, the signal began to attenuate.  Not bad for pushing a low-end scope way beyond its limits!


cornel-scopeNext up is [Bruce Land] with his PIC32 oscilloscope. Microcontroller scope projects are nothing new, but one that runs at nearly 1 MHz sampling rate while generating NTSC composite video is nothing to sneeze at. [Bruce] pulled this off by using Direct Memory Access (DMA) to move the data from the ADC to memory, and to get the video data from memory to the I/O pins used to generate video. The video itself is created by a resistor tree DAC. All you need to make black and white video is three resistors and two I/O pins. [Bruce] says the entire scope cost about $4.00 us in parts!

scope-hand[Jacob Christ] mixed art and science with his chipKIT Oscilloscope Plotter. [Jacob] used a Microchip PIC32 based Fubarino to draw patterns on his scope. To do this the scope must be set to X-Y mode. [Jacob] paired his Fubarino with a MCP4902 Digital to Analog Converter (DAC). Using a dedicated DAC is a great way to do this. [Jacob’s] images are a testament to that, as they’re some of the cleanest “scope art” drawings we’ve seen. Much like [Bruce Land], [Jacob] used his project as the basis for a college class. In fact, the image to the left was created by one of his students!

Want more scope goodness? Check out our new Oscilloscope Projects List!

Hackaday.io Update!

Hackaday.io is getting new features every day. Our dev team has just rolled out a new gallery view. Just click on a project’s featured image, or the “View Gallery” button, and you will be taken to a gallery view of every image used in the project – including log images. YouTube videos will render in the gallery as well. It’s a great way to view a timeline of progress for some of the projects on hackaday.io. For a great example of this, check out OpenMV’s gallery.

In other Hackaday.io news, check out the Caption CERN Contest! Every week we put up a new image from CERN’s archives. The Hackaday.io user who comes up with the funniest caption wins a T-Shirt from The Hackaday Store!

Looks like we’ve hit the end of the trace for this Hacklet. Same hack time, same hack channel, bringing you the best of Hackaday.io!

EddiePlus, the Edison based balancing robot

[Renee] dropped a tip to let us know about EddiePlus, her balancing robot creation. As its name might imply, EddiePlus is controlled by an Intel Edison processor. More specifically, [Renee] is using several of Sparkfun’s Edison Blocks to create Eddie’s brain. EddiePlus’ body is 3D printed, while his movement comes from two Pololu DC motors with wheels and encoders. The full build instructions are available as a PDF from [Renee’s] Google drive.

Eddie is able to balance and drive around on two wheels, much like a Segway. Sensor data for balance comes from Sparkfun’s LSM9DS0 based Inertial Measurement Unit (IMU) block. In this new “plus” version of Eddie, [Renee] has added encoders to the robot’s wheels. This makes it easier for him to adapt to changing loads – such as pumping iron (or banana plugs as the case may be). The encoders also help with varying terrain, as [Renee] demonstrates by tilting a board as Eddie drives on it. Eddie’s code is written in C, and available on Github.  Controlling Eddie is as easy as sending simple commands via UDP.

As you might imagine, the Intel Edison still has plenty of cycles left over after computing Eddie’s balance. [Renee] uses some of these with a webcam based teleoperation mode.

Click past the break to see Eddie in action!

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Wearable WiFi Finder Uses the ESP8266

It seems like a day doesn’t go by without an ESP8266 project here on Hackaday. There’s a good reason for that, the chip and associated modules have brought low-cost WiFi connectivity to the masses. Today we have [Stevica Kuharski], who has built an open WiFi access point detector using the ESP8266. To do this he’s using the Lua compatible NodeMcu firwmare. [Stevica] wrote his own Lua scripts to run on the ESP8266’s internal 32 bit microcontroller. The freewifi script scans and searches for open WiFi networks. If a network is detected, the user is informed via a blinking LED.

To make the project wearable, [Stevica] powered the project with a pair of CR2450 coin cell batteries. The ESP8266 is not known for being a particularly low power device, so we’re curious to see what sort of battery life  [Stevica] gets with his project. The project source is already available on GitHub, and [Stevica] is hoping to kick off an Indiegogo campaign in the next few weeks. Click past the break to see the WiFi detector in action.

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Spin up an old hard drive with a solenoid motor

Just about all of us have a few old hard drives in our junk box. There are a myriad of projects out there to put them to work in new and interesting ways. One of those ways is to turn your hard drive into a solenoid motor of sorts. (YouTube link) This isn’t a new hack, videos of it have been kicking around the internet for years. [black1985vette] gives a pretty good explanation of how he’s done it. He used a piece of brass as a connecting rod between the drive head and a pin mounted off-center to the platter hub. One of the platter mounting screws provides the perfect place to set the pin. A bent safety-pin rubs the center of the hub, which is partially insulated with tape. When the pin contacts the hub, the drive head is energized, pushing the whole assembly around. The mass of the platters acts as a flywheel, carrying the motor the rest of the way around.

[Pulverrostmannen] performed a similar mod, though he used a micro switch to time the drive head. Rather than a brass connecting rod, [Pulverrostmannen] used a spare head. With a simple transistor circuit acting as a speed control, his hard drive motor revved up to around 1560 RPM, which is pretty respectable for a bunch of junk parts.

So next time you’re stuck in on cold rainy weekend, pull out some of those old drives and get hacking! Click past the break to several of these projects in action.

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