NixieBot Films Your Tweets

[Robin Bussell]’s NixieBot is a mash up of new age electronics and retro vintage components and he’s got a bunch of hacks crammed in there. It’s a Nixie tube clock which displays tweets, takes pictures of the display when it encounters tweets with a #NixieBotShowMe hash tag, and then posts requested pictures back to twitter. If a word is eight characters, it takes a snapshot. If it’s a longer message, NixieBot takes a series of pictures of each word, converts it to an animated GIF, and then posts the tweet. In between, it displays random tweets every twenty seconds. You can see the camera setup in the image below and you should check out the @nixiebot twitter feed to see some of the action.

For the display, he’s using eight big vintage Burroughs B7971 Nixie Tubes. These aren’t easy to source, and current prices hover around $100 each if you can find them. The 170V DC needed to run each tube comes from a set of six 12V to 170V converter boards specifically designed to drive these tubes. Each board can drive at least a couple of nixies, so [Robin]’s able to use just four boards for the eight tubes. Each nixie is driven by its own “B7971 SmartSocket“, a dedicated PIC16F690 micro-controller board custom designed for the purpose. A serial protocol makes it easy to daisy-chain the SmartSockets to build multi character displays.

The rest of the build is pretty straight forward. A Raspberry-Pi running Twython for Twitter communications, GrafixMagick for GIF creation, Picamera for taking pictures and GPIO libraries for controlling the display. The software to run all of this is hosted on his GitHub repository with some basic instructions on how to put it together.

A more detailed reference is available on the NixieBot blog. He’s designed a Pi shield board to house the high voltage modules, a 5V DC-DC converter and the Pi GPIO header. He’s probably got a few more to spare, so with a bit of luck in finding the elusive Nixie tubes, and some deep pockets, it ought to be relatively easy to build your version of the NixieBot.

And if the NixieBot has got your interest piqued, check out “The Art of making a Nixie Tube” featuring the work of [Dalibor Farnby].

Filed under: Raspberry Pi

One Bit, One Instruction Discrete CPU

There is a certain benefit to being an early adopter. If you were around when Unix or MSDOS had a handful of commands, it wasn’t hard to learn. Then you learn new things as they come along. If you started learning Linux or Windows today, there’s a huge number of details you have to tackle. You have the same problem trying to learn CPU design. Grappling with the design of a 16-bit CPU with a straightforward data path is hard enough. Throw in modern superscalar execution, pipelining, multiple levels of microcode, speculative execution, and all the other features modern processors have and you’ll quickly find yourself lost in the details.

[Michai Ramakers] wanted to build an educational CPU and he took a novel approach. The transistor CPU uses only one instruction and operates on one bit at a time. Naturally, this leads to a small data path, which is a good thing if you’re only using discrete transistors. His website is a ground-up tutorial in building and using the tiny computer.

The programming of the device is a bit odd. Each instruction is 32 bits wide (the CPU has a Harvard-like architecture where data and instruction memory is different). The instructions have only two parts. One is a data memory address and the second is a program address. The CPU inverts the value at the data address and then either loads the next instruction or the one specified by the second part of the instruction, depending on the value of the bit after inversion.

Each instruction is effectively an “invert and jump if result is zero.” Most one-instruction CPUs use a transfer architecture or a logical/mathematical function and conditional jump (usually subtract or nor). This design fits in the latter category.

We’ve covered many one instruction computers in the past. There’s a wide variety in how they work. We’ve even seen another 1-bit machine. I wouldn’t suggest building it out of transistors, but I once did my own take on a single instruction 32-bit CPU that programmed in Forth, supported interrupts, and could run pretty much the same kind of tasks any modern CPU could do.

Filed under: computer hacks

“OK Google” support finally comes to Android Auto

Arm Thusters, For Underwater Super Powers!

Most of us will have spent the idle hours of our youth while sitting in a room where a teacher was standing at the blackboard explaining iambic pentameter or the Diet of Wurms, daydreaming about the amazing exploits we could have created if only we had an Evil Lair stuffed with all the tools our fertile imaginations demanded. [James Bond] would have had nothing on us, our personal [Q] branch would have ensured we would have had the coolest gadgets on the planet.

As grown-ups we have some of the resources to make this a reality, yet somehow we’ve never made good on the dream. We spend our time creating IoT clocks or novelty electronic Christmas ornaments, and Mr. [Bond] still has a monopoly on the really cool stuff. Fortunately [PeterSripol] has struck a blow on our behalf, because he’s created a pair of arm-mounted underwater thrusters (YouTube, embedded below) that should leave [007] feeling definitely a bit [006.5].

The thrusters themselves came from a Kickstarter purchase that he left on the shelf for a while without an application. Then with only a short time before a trip to Hawaii, he set to work to do something with them, and the arm thrusters were the result.

He makes extensive use of components from the world of radio controlled models, with battery packs and speed controllers mounted in a waterproof food container at his belt, and a pair of handheld microswitch controllers. There is an Arduino which presumably produces the PWM signal, and we are treated to an in-depth look at his waterproofing efforts for the various connectors and switches. After a false start with battery polarity and a cracked impeller housing the device works, and we see it in use on a suitably tropical though not quite sun-kissed beach.

The thrusters appear to work very well, and we’d say they look a lot of fun to use. Sadly the exercise is brought to a halt when a control wire is sucked into a propeller, but we’re sure that’s only a minor setback. We’ve posted the video below the break, take a look.

This seems to be the first wearable underwater thruster project we’ve shown you here at Hackaday. However we’ve given you at least one roundup of underwater ROVs.

Thanks [Andre] for the tip.

Filed under: transportation hacks

FDA approves late-stage clinical trial of ecstasy for PTSD treatment

The Hunt For Red October In A Bathtub

Anything can be a remote controlled airplane, and ‘copters – quad or not – simply beat the air into submission. Remote controlled cars are easy, and RC tanks can even shoot their guns. One type of vehicle has eluded remote control hobbyists to a large extent; building a remote control submarine is hard. Not only do you have buoyancy to worry about, but you also need a way to keep the dry parts dry, all while operating in an environment where radio doesn’t really work well.

[Ivan] has already built RC planes, but wanted to tackle a new challenge. He built an RC submarine, and he did it using the simplest household materials.

There are three main challenges to building a submarine. These are the radio system, building a watertight enclosure, and having some sort of ballast tank to pump water into and out of. For the radio system, the now ubiquitous 2.4 GHz radios do not function underwater. Those older radios operating on 27, 40, or 72 MHz do, and after someone heard of [Ivan]’s submarine project, a few junk drawers were scavenged netting a radio system for this sub.

Watertightness was accomplished with a 75mm diameter piece of PVC pipe, capped with plugs and o-rings at both ends. We read on the Internet that using PVC pipe as a pressure vessel has been responsible for more deaths than millennia of plague and war; in this case, it almost works – instead of inevitably exploding, the PVC sub is only in danger of imploding when placed in a bathtub. That’s a completely different failure mode that should allay the fears of even the most vocal critics.

Being able to go underwater doesn’t mean anything unless you can dive and surface again. To do this, [Ivan]’s submarine is using a large syringe attached to a peristaltic pump. To dive, [Ivan] commands the sub to pump water into the syringe. To surface again, the sub pumps water out of the syringe.

On [Ivan]’s blog, you can find links to all the items used in the construction, a few more pics, and a video, also found below.

 

Filed under: robots hacks

The Open-V, World’s First RISC-V-based Open Source Microcontroller

An fully open source, Arduino-compatible microcontoller based on the RISC-V architecture.

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