A Talking Reverse Geocache Puzzle Box

January 20, 2012 by Mike Szczys 2 Comments

Here’s a talking reverse geocache puzzle box which [Erv Plecter] built as a wedding gift for his friends. The box itself isn’t really the gift, but a surprise delivery system for a collection of cash from the couple’s circle of friends to go toward the honeymoon. We think this is about fifty times more fun that getting a fat envelope of bills. Who would really expect to find cash inside once you finally get to the target location?

Unlike the other geocache box we saw recently, this one has no display to show you clues to the destination. Instead, it plays back audio clips which [Erv] recorded himself. They’re quite tongue-in-cheek which is another nice personal touch. The pin seen protruding out of the right side of the box can be removed to play a clue and check the location. It’s connected by a little chain to a 5 euro-cent piece which conceals an emergency release mechanism for the lid. The device is powered with a Lithium battery and can be recharged without opening the box via a USB port in the side.

We’ve embedded the video demonstration of the box after the break.

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Numerous Quiz Buttons Built On The Cheap

January 20, 2012 by Mike Szczys 3 Comments

[Sprite_TM] was tapped to build a rather large quiz buzzer system. Judging from his past work we’re not surprised that he seemed to have no trouble fulfilling the request. As the system is not likely to be used again (or rarely if it is) he found a way to finish the project that was both quick and inexpensive.

Each buzzer consists of a base, a button (both mechanical and electrical), and a couple of LEDs to indicate who buzzed in first. The mechanical part of the button uses a plastic bowl from Ikea and a wooden dowel surrounded by some pipe insulation. A momentary push switch is glued on the top of that dowel, and the insulation projects above that just a bit. This way it acts as a spring. The Dowel has been sized so that the bowl lip will hit the wooden base just as it clicks the switch.

As you can see, all of the buzzers are interlinked using Ethernet cable. The real trick here is how to read 14 buttons using just one CAT5 cable. This is done with the clever use of a 4×4 button matrix for a total of 16 buttons. The matrix also includes the LEDs for each buzzer. Since CAT5 has four twisted pairs this works out perfectly.

Looking for a more robust system thank this? Here’s a pretty nice one.

Simple Machining Process Repairs Broken Control Knob

January 20, 2012 by Mike Szczys 49 Comments

[Francisco] is helping his mother with a repair to the headlight knob on her Ford Ranger. Above you can see the broken knob on the left, and what it is supposed to look like on the right (taken from [Francisco’s] own vehicle for reference). We’ve encountered split shafts on plastic knobs before and decided it was not something that could be fixed. But he didn’t give up so easily. He mentions that you can purchase a replacement for a few bucks, but he has the means to repair the knob by machining a metal bushing.

The idea is that you mill a metal ring whose inner diameter matches what the outer diameter of the plastic shaft should be. By inserting the broken knob in the ring, the plastic is held tightly together as if it had never broken. In the video after the break [Francisco] uses a metal pencil body from his junk box and a mini-lathe to cut the bushing to length, and mill the inner diameter to his specifications.

He talks about the difficulty of getting replacement parts in Chile, where he lives. But we think this kind of thrift is a great example for all hackers. If you’ve got the tools why not use them? And if you don’t have them, here’s a great excuse to procure them!

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FPGA Snake Game Uses No VHDL At All

January 20, 2012 by Mike Szczys 18 Comments

We’re really not supposed to start a feature like this; but this hack is awesome. It’s a game of Snake implemented by an FPGA dev board. It uses a 16×16 LED matrix as the display and an SNES controller for input. So far it sounds like a very normal version of the game. But as you start to hear how it works in the presentation after the break you fall in love with what’s going on here.

First of all, it’s not written in VHDL — the predominant programming language for FPGAs. Instead, [Darrell] used the schematic-only approach to build the logic. Okay, that’s starting to get more interesting. As he continues to explain the circuit we get to see how the control input works (pretty simple since the SNES controller uses a parallel-to-serial shift register) and how the display is multiplexed. But the actual game logic is where things really take off. Each pixel in the display has its own individual logic circuit. Basically every cell is its own processor which reacts both to what is passed into it, as well as to a random seed. That seed system is called the ‘bucket brigade’ and passes a chance to spawn a piece of food from one cell to the next. All of this together makes for one simple game that is eloquently executed. Continue reading “FPGA Snake Game Uses No VHDL At All” →

NES Controller Uses Capacitive Touch Instead Of Buttons

January 19, 2012 by Mike Szczys 29 Comments

Here’s one way to really keep the component count low. [David] developed an NES controller that doesn’t use any buttons. The copper clad has been milled to provide a pad which registers a button push based on capacitance. The board has a SIL header at the top, making it easy to plug into the Arduino board that reads the inputs.

[David] had trouble getting the Arduino pin read functions to respond fast enough for he NES console’s expectations. He ended up using commands to access the ATmega’s peripherals directly in order to achieve the target timing. Speaking of, he did his own sniffing of the communication scheme using a logic analyzer. The results of that work, as well as the board files and code are available at the site linked above. And there’s a demo of the controller used to play Super Mario Bros. in the clip after the break.

This is actually a tangential project using a PCB mill which he’s developing through Kickstarter. This certainly shows that the mills works as designed. Continue reading “NES Controller Uses Capacitive Touch Instead Of Buttons” →

Ball-in-maze Game Shows Creativity And Classic 8-bit Sound

January 19, 2012 by Mike Szczys 4 Comments

[M. Eric Carr] built this a long time ago as his Senior Project for EET480. It’s an electronic version of the ball-in-maze game. We’ve embedded this video after the break for your convenience.

The game has just one input; an accelerometer. If you’re having trouble visualizing the game, it works the same as this Android-based version, but replaces the physical maze and marble with a virtual maze on the graphic LCD screen. This has huge implications. Instead of just recreating the maze on the screen, [Eric] designed a multi-screen world, complete with warp blocks, which adds difficulty to finding a solution. It also means that multiple different mazes can be played if you get tired of playing the same level.

This game also features music. A separate PIC microcontroller uses PWM to push out the 8-bit sound heard in the video. From the YouTube comments we learned that [Eric] didn’t write the music himself, but we still appreciate the playback quality he achieves with his hardware.

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Complete Guide To Compiling OpenWRT

January 19, 2012 by Mike Szczys 9 Comments

Regular reader [MS3FGX] recently wrote a guide to compiling OpenWRT from source. You may be wondering why directions for compiling an open source program warrant this kind of attention. The size and scope of the package make it difficult to traverse the options available to you at each point in the process, but [MS3FGX] adds clarity by discussion as much as possible along the way.

OpenWRT is an open source alternative firmware package that runs on may routers. It started as a way to unlock the potential of the Linksys WRT54G. But the versatility of the user interface, and the accessibility of the Linux kernel made it a must-have for any router. This is part of what has complicated the build process. There are many different architectures supported and you’ve got to configure the package to build for your specific hardware (or risk a bad firmware flash!).

You’ll need some hefty hardware to ease the processing time. The source package is about 300 MB but after compilation the disk usage will reach into the Gigabyte range. [MS3FGX] used a 6-core processor for compilation and it still took over 20 minutes for a bare-bones distribution. No wonder pre-built binaries are the only thing we’ve ever tried. But this is a good way to introduce yourself to the inner workings of the package and might make for a ~~frustrating~~ fun weekend project.