The Most Random Electronic Dice Yet


If you’ve written a great library to generate random numbers with a microcontroller, what’s the first thing you would do? Build an electronic pair of dice, of course.

[Walter] created the entropy library for AVRs for a reliable source of true random numbers. It works by using the watchdog timer’s natural jitter; not fast by any means but most sources of entropy aren’t that fast anyway. By sampling a whole lot of AVR chips and doing a few statistical tests, it turns out this library is actually a pretty good source of randomness, at least as good as a pair of dice.

The circuit itself uses two 8×8 LED matrices from Adafruit, an Arduino, and a pair of buttons. The supported modes are 2d6, 2d4, 2d8, 2d10, 1d12, 1d20, a deck of cards, a single hex number, a single 8-bit binary number, or an eight character alphanumeric password. It’s more than enough for D&D or when you really need an unguessable password. Video demo below.

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This Sassy Art Installation is Like The Stanley Parable for the Telephone

Insert Customer Feedback Here

Imagine this. A phone on a nearby desk starts ringing. No one is around to pick it up, so you decide that you will be a good Samaritan and answer the phone. You are greeted by a slightly creepy robotic female voice asking you to complete a simple survey. Having nothing else to do, you go ahead and run through the telephone survey. As you start answering the questions, things start to get a bit… weird. The robot voice doesn’t like your answers. She actually disagrees with you, and she does NOT like being interrupted. Now she’s getting sassy with you! What is going on here?

Most likely you are the latest victim of Insert Customer Feedback Here, [Charles'] art installation. You see, that is no ordinary telephone. [Charles] actually removed the guts of an old telephone and replaced them with an Arduino. The Arduino periodically rings the phone, waiting for someone to answer. Once the phone is off the hook, the Arduino uses a Wave shield to start playing back the scripted audio files. All of the text-to-speech files and the various hold music files are played back with the wave shield. The Arduino is also hooked up to the 1, 2, 3, and # keys of the telephone keypad in order to read back the user’s responses.

From here on out the program acts as a sort of “choose your own adventure” game. The program takes different paths and responds in different ways depending on how the user answers the questions. Generally speaking, it will get more “irritated” towards the user if it doesn’t “like” your answers, otherwise it will get less irritated. The hold music will even change to become more or less aggressive.

It’s easy to draw comparisons to Portal’s GLaDOS due to the robotic female voice and to the narrator from The Stanley Parable for the “choose your own adventure” feeling. In fact, if GLaDOS and The Stanley Parable had offspring, this would surely be it. This project brings that same type of silly sarcastic humor to a different medium and it does it well. Be sure to watch the video of the system in action below. It really starts to get interesting around the 1:15 mark. [Read more...]

MakerBot Files Patents, Internet Goes Crazy


In the past month, a few patent applications from MakerBot were published, and like everything tangentially related to the prodigal son of the 3D printer world, the Internet arose in a clamor that would be comparable only to news that grumpy cat has died. That’s just an analogy, by the way. Grumpy cat is fine.

The first patent, titled, Three-dimensional printer with force detection was filed on October 29th, 2013. It describes a 3D printer with a sensor coupled to the hot end able to sense a contact force between the nozzle and build plate. It’s a rather clever idea that will allow any 3D printer to perform software calibration of the build plate, ensuring everything is printed on a nice, level surface. Interestingly, [Steve Graber] posted an extremely similar design of a bed leveling probe on October 6th, 2013. In [Steve]‘s video, you can see his bed level probe doing just about everything the MakerBot patent claims, all while being uploaded to YouTube before the patent application.

When it rains it pours, and the Quick-release extruder patent application, filed on October 28, 2013, bears this out. It claims an extruder that includes, “a bistable lever including a mechanical linkage to the bearing, the bearing engaged with the drive gear when the bistable lever is in a first position and the bearing disengaged from the drive gear when the bistable lever is in a second position.” Simple enough, a lever with two positions, where one presses a bearing against a drive gear, and the other position disengages the bearing from a drive gear. Here’s something that was published on Thingiverse in 2011 that does the same thing. Hugely famous RepRap contributor [whosawhatsis] has weighed in on this as well.

It is important to note that these are patent applications. Nothing has been patented yet. The US Patent and Trademark Office does seem to have a lot of rubber stamps these days, so what is the average Internet denizen to do? Here are easy to follow, step-by-step instructions on how to notify the USPTO of prior art. Remember, just because prior art does not completely invalidate a patent application’s claims doesn’t mean you shouldn’t send it in. It is a patent examiner’s job to review the prior art.

So there you go. MakerBot applies for patents, people complain, but not to the USPTO. Highly relevant video and transcription below.

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Never Miss a Thing With This Programmable Vacuum Fluorescent Display Ticker

VFD Ticker

[Coyt] wanted a more convenient way to keep up to date with the ever-changing Bitcoin exchange rates, as well as weather and other useful information. He realized that the vacuum fluorescent display (VFD) he had purchased a couple of years ago would be perfect to display small amounts of information.

[Coyt] discovered that the VFD had a serial interface. The problem was that the VFD was looking for a 12V serial signal but the Raspberry Pi he wanted to use runs at a 3.3V. Upon closer inspection [Coyt] discovered that the VFD actually ran at lower levels as well, but it had a level converter chip installed in front of the main connector. He simply bypassed the level converter and was then able to get the RasPi speaking directly to the VFD.

The brain running this display is a Raspberry Pi. The Pi runs a Python script that pulls down all of the relevant information from the internet and displays it on the VFD. [Coyt] didn’t stop there, though. He knew that having the screen on all of the time would be somewhat of a waste, so he hooked up a PIR sensor to automatically turn on the display only when needed. The PIR sensor can detect motion in the room and will disable the display after a set period of inactivity. Most of this is powered by an LM7805 voltage regulator. While [Coyt] admits a linear regulator is not his ideal solution, it does get the job done. The metal stand acts as a nice heat sink for the regulator.

[Coyt] also wanted his project to have a certain aesthetic. He started by bending a metal plate into a stand for the electronics. He then mounted the VFD on the front of the stand and the RasPi on the back. He also mounted green LEDs between the two plates to light up the edges for a little extra pizzazz. [Coyt] believes he can use the RasPi to PWM the LEDs but this has not yet been implemented. This would allow him to pulse the light for added effect.

Since the whole thing is run by a Python script, it would be trivial to modify it to display other kinds of information. What would you do if you had a motion sensitive automatic ticker?


Dodgy Hotel, Beer and A WWII Era Tube Receiver

bc-22e ww2 reciever operating in a hotel

In the luxurious accommodations provided by Motel 8 and armed only with a few tools and a six pack – a pair of amateur radio enthusiasts attempted the repair of an old WWII era BC-224E receiver. They picked up the boat anchor antique receiver, which was in unknown condition, from a flea market while in town for the Dayton Hamvention, brought it back to their hotel and got to work.

The BC-224E came in two parts – the receiver and the power supply. The speaker for the system, which is actually located in the power supply, is driven by a large inductor.  Apparently when the receiver was constructed, the permanent magnets of the day were not powerful enough to drive a speaker.

Fortunately, the receiver also came with some schematics, allowing [Gregory] and his fellow radio enthusiast to reverse engineer the power supply. After a few tweaks and cap swaps, they crossed their fingers and plugged it in. Stay tuned to see what happened next.

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Discovering a Wifi Enabled 10MHz Oscilloscope


As most of our readers know, [Mike] was visiting Bay Area Maker Faire  last weekend with a big Jolly Wrencher on his back. During his tour he encountered the neat oscilloscope shown in the video above, made by the Belgian company Velleman. Even though it only has a 10MS/s sampling rate and a 10MHz bandwidth, our guess is that it may still be useful for some hobbyists out there as it can communicate with any PC/smartphone/tablet using its Wifi interface.

Inside the black box is a 3.7V 1800mAh Li-ion battery with a USB port to recharge it or update the oscilloscope’s firmware. As seen in the video, the tablet’s touchscreens may enable more natural interaction with the user interface. The protocol used to export the acquired samples is open, which may allow users to create their own analysis program. The oscilloscope uses an 8 bit analog to digital converter and a 4K samples buffer.

Electromagnetic Boots For All Your Upside Down Needs!

magnet boots

X-Men: Days of Future Past is making its way to theaters around the world, and [Mr. Furze] has released his second X-Men related hack — Magneto Boots.

In case you missed it, [Colin Furze] has made three projects to celebrate geekdom and a mastery of fabrication for all the comic book fans out there. He started with the fully functional pneumatic Wolverine Claws, and now he’s tackling Magneto’s powers. The third project isn’t out quite yet, but we can’t wait to see the final installment!

Now the problem with Magneto is his powers are a wee bit too… magical? Without special effects, you can’t really replicate his mutant abilities (please prove us wrong if you can!), so [Colin] decided to do the next best thing. Magnetize himself — well, his shoes.

[Read more...]


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