Tic-Tac-Toe, In TTL

June 29, 2019 by 15 Comments

We’ll all be familiar with Tic-Tac-Toe, or Noughts and Crosses, a childhood pencil-and-paper diversion which has formed the basis of many a coding exercise. It’s an easy enough task to implement in software, but how many of us have seen it done in hardware alone? That’s just what [Warren Toomey] has done using TTL chips, and his method makes for a surprisingly simple circuit.

At its heart is an 8 kB ROM that contains precomputed move sequences that are selected via an address composed of the game states for both player and machine. A series of flip-flops control and buttons to make the board, and a 555 provides a clock.

The technique of using a ROM to replace complex logic is a very powerful one that is facilitated by the low price of relatively large devices that would once have been unaffordable. We’ve seen the technique used elsewhere, including as an ALU in a TTL CPU, and even for an entire CPU in its own right.

You can see the result in operation in the video below the break, and should you wish to have a go for yourself all the relevant information can be found in a GitHub repository.

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A Doom-esque Port To The ATmega328

June 29, 2019 by 11 Comments

Doom holds a special place as one of the biggest games of the 1990s, as well as being one of the foundational blocks of the FPS genre. Long before 3D accelerators hit the market, iD Software’s hit was being played on computers worldwide, and later spread to all manner of other platforms. [David Ruiz] decided to build a cutdown version for everyone’s favourite, the ATmega328.

Due to the limited resources available, it’s not a direct port of Doom. [David] instead took some sprites and map data from the original game, and built a raycasting engine similar to that of Wolfenstein 3D. Despite the limited memory and CPU cycles, the basic game can run at between 8-11 FPS. There are fancy dithering tricks to help improve the sense of depth, a simplified enemy AI, and even a custom text library for generating the UI.

It’s a great example of what can be done with a seemingly underpowered part. We’ve seen similar work before, with Star Fox replicated on the Arduboy. A hacker’s ingenuity truly knows no bounds.

 

Parallel Processing Was Never Quite Done Like This

June 29, 2019 by 64 Comments

Parallel processing is an idea that will be familiar to most readers. Few of you will not be reading this on a device with only one processor core, and quite a few of you will have experimented with clusters of Raspberry Pi or similar SBCs. Instead of one processor doing tasks sequentially, the idea goes, take a bunch of processors and hand out the tasks to be done simultaneously.

It’s a fair bet though that few of you will have designed and constructed your own parallel processing architecture. [BB] sends us a link which though it’s an old one is interesting enough to bring you today: [Michael] created a massively parallel array of Parallax Propeller microcontrollers back in 2008, and he did so on a breadboard.

The Parallax Propeller is an 8-core RISC microcontroller from the company that had found success in the 1990s with the BASIC Stamp, the PIC-based board that was all the rage before Arduino came into the world. In the last decade it was seen as an extremely exciting prospect, but high price and arcane development tools compared to a new generation of low-cost and easy to code competitors meant that it never quite caught on and remains today something of an intriguing oddity. So today’s value in this project lies not in something that you should run out and do yourselves, but instead in what the work tells us about the nuts and bolts of parallel processing architecture. It involves more than simply hooking up a load of chips and hoping for the best, and we gain some insight into the different strategies involved.

The Propeller certainly wasn’t the first attempt at a massively parallel microcontroller, and we doubt it will be the last. We’re certainly seeing microcontrollers with more than one core becoming more mainstream even in our community, but even with those how many of you have made use of the second core in your dual-core ESP32? Is a multicore microcontroller a solution searching for a problem, or will somebody one day crack it and the world will never be the same again? As always, the comments are below.

Electronic Candle Charges Inductively

June 28, 2019 by 1 Comment

Humans like things that look like other things. A great example are faux LED tea light candles, with a plastic “flame” and flickering orange LED to recreate the effect of their waxy brethren. [gzumwalt] wanted to take the concept a little further, however, and got down to work.

The design harvests the orange LED and flame lens from an existing LED candle, but the rest is all original. [gzumwalt] printed a full-size candle, and fitted it with inductive charging hardware and a lithium-polymer battery. A corresponding charging base is used to supply power to the candle when it’s not in use. This is all handled automatically, with neodymium magnets used to activate reed switches to turn the charger on and the LED off.

It’s a tidy build that can be easily replicated with a 3D printer and some off-the-shelf parts. It’s also less wasteful than using disposable batteries, and safer than using real candles – so if you find yourself routinely shooting candle scenes in your budget film studio, it might be worth printing up a set of these.

LED candles range from the basic to the extreme – we’ve seen builds so realistic, you can light them with a match.

A Super Tidy School Bus RV Conversion

June 28, 2019 by 18 Comments

Many of us have seen an old bus for sale for a tantalizingly low price, and begun thinking about the possibilities. [EpiclyEpicEthan1] is someone who took the next step, bought the bus, and got to work converting it to an RV, with impressive results.

The bus in question is a 2002 International RE3000, which in its former life had helped move school children and barrels of pool chemicals to and fro. The project began, as many do, with a full teardown of the interior. With this done, the floor was treated to remove rust and repainted. Insulation and new plywood boards were then installed, and the fit-out began.

The amount of work involved in the build is immense. There’s a master bedroom, auxiliary bedroom, bathroom, and kitchen area. It’s a fully featured RV in every sense of the word, and yes, there is hot water. There was also significant work done to improve the driving experience, with switches relocated, lights added, and a reversing camera installed for easier parking.

Overall, it’s an impressive project that should serve as great inspiration to anyone wanting to attempt something similar. Then again, if your means are a little more limited, you could always go for a Corolla build.

Syringe Pump Turns CNC Machine Into A Frosting Bot

June 28, 2019 by 3 Comments

“Amazing how with only the power of 3D-printing, two different computers, hundreds of dollars in CNC machinery, a lathe, and modern microcontroller magic, I can almost decorate a cupcake as well as a hyperactive ten-year-old.”  We can think of no better way to sum up [Justin]’s experiment in CNC frosting application, which turns out to only be a gateway to more interesting use cases down the road.

Granted, it didn’t have to be this hard. [Justin] freely admits that he took the hard road and made parts where off-the-shelf components would have been fine. The design for the syringe pump was downloaded from Thingiverse and does just about what you’d expect – it uses a stepper motor to press down on the plunger of a 20-ml syringe full of frosting. Temporarily attached in place of the spindle on a CNC router, the pump dispenses onto the baked goods of your choice, although with an irregular surface like a muffin top the results are a bit rough. The extruded frosting tends to tear off and drop to the surface of the cake, distorting the design. We’d suggest mapping the Z-height of the cupcake first so the frosting can dispense from a consistent height.

Quality of the results is not really the point, though. As [Justin] teases, this hardware is in support of bioprinting of hydrogels, along with making synthetic opals. We’re looking forward to those projects, but in the meantime, maybe we can all just enjoy a spider silk beer with [Justin].

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Fish Hooks Embedded In Robot Toes Make Them Climb Like Cockroaches

June 28, 2019 by 5 Comments

Take a dozen or so fish hooks, progressively embed them in plastic with a 3D printer and attach them to the feet of your hexapod and you’ve got a giant cockroach!

Fish hooks embedded in 3D-printed robot feet

A team of researchers at Carnagie Mellon University came up with this ingenious hack which can easily be copied by anybody with a hexpod and a 3D printer. Here you can see the hooks embedded into the ends of a leg. This ‘Microspine technology’ enables their T-RHex robot to climb up walls at a slightly under-whelming 55 degrees, but also grants the ability to cling on severe overhangs.

Our interpretation of these results is that the robot needs to release and place each foot in a much more controlled manner to stop it from falling backwards. But researchers do have plans to help improve on that behavior in the near future.

Sensing and Closed Loop Control: As of now, T-RHex moves with an entirely open-loop, scripted gait. We believe that performance can be improved by adding torque sensing to the leg and tail actuators, which would allow the robot to adapt to large-scale surface irregularities in the wall, detect leg slip before catastrophic detachment,and automatically use the tail to balance during wall climbs.This design path would require a platform overhaul, but offers a promising controls-based solution to the shortcomings of our gait design.

No doubt we will all now want to build cockroaches that will out perform the T-RHex. Embedding fish hooks into plastic is done one at a time. During fabrication, the printer is stopped and a hook is carefully laid down by human hand. The printer is turned on once again and another layer of plastic laid down to fully encapsulate the hook. Repeat again and again!

Your robot would need the aforementioned sensing and closed loop control and also the ‘normal’ array of sensors and cameras to enable autonomy with the ability to assess the terrain ahead. Good luck, and don’t forget to post about your projects (check out Hackaday.io if you need somewhere to do this) and tip us off about it! We’ve seen plenty of, sometimes terrifying, hexapod projects, but watch out that the project budget does not get totally out of control (more to be said about this in the future).

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