Fail of the Week: Electrically Effective Emulators Exceed Enclosure, Enrage Engineer

After a few years of on and off development, [Steve] from Big Mess ‘o Wires completed work on a floppy disk drive emulator for older Macs such as the Plus. The emu plugs into the DB-19 port on the Mac and acts just like a 3.5″ floppy, using an SD card to store the images. He’s been selling the floppy emus for about the last year, and assembled the first several scores of them himself. At some point, he enlisted a board house to make them, and as of November 2014, he’s had enclosures available in both clear acrylic and brown hardboard.

[Steve] recently ran out of emu stock, so it was time to call up the board house and get some more assembled. After waiting six weeks, they finally showed up. But in spite of [Steve]’s clear and correct instructions, all 100 boards are messed up. One resistor is missing altogether, and they transposed a part between the extension cable adapter board, connecting it directly to the emu main board. But get this: the boards still work electrically. They don’t fit in the housings, however, and the extension cables are useless. After explaining the situation, the board house agreed to cook up a new batch of boards, which [Steve] is waiting patiently to receive.


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Fail of the Week: Cat6 != Coax

With a new Kenwood 5.1 receiver acquired from questionable sources, [PodeCoet] had no way to buy the necessary coax. He did have leftover Cat6 though. He knew that digital requires shielded cable, but figured hacking a solution was worth a try.

HAD - Coaxfail4To give hacking credit where credit is due, [PodeCoet] spent over a decade enjoying home theatre courtesy of a car amp rigged to his bench supply. Not all that ghetto of a choice for an EE student, it at least worked. To hook up its replacement he pondered if Cat6 would suffice, “Something-something twisted pair, single-sideband standing wave black magic.” Clearly hovering at that most dangerous level of knowledge where one knows just enough to get further into trouble, he selected the “twistiest” (orange) pair of wires in the cables. Reasonable logic, one must select the strongest of available shoelaces for towing a car.

Continue reading “Fail of the Week: Cat6 != Coax”

Fail of the Week: Teddy Top and Fourteen Fails

Last summer, [Quinn] made the trip out to KansasFest, the annual Apple II convention in Kansas City, MO. There, she picked up the most modern Apple II system that wasn’t an architecturally weird IIGS: she lugged home an Apple IIc+, a weird little machine that looks like an old-school laptop without a screen.

Not content with letting an old computer just sit on a shelf looking pretty, [Quinn] is working on a project called the Teddy Top. ‘Teddy’ was one of the code names for the Apple IIc, and although add-ons to turn this book-sized computer into something like a laptop existed in the 80s, these solutions have not withstood the test of time. [Quinn] is building her own clamshell addition to her IIc+, and somehow failing at something she’s done hundreds of times before.

While the IIc+ has an NTSC composite output, the super-special video add-ons for the IIc+ used a DB15 expansion connector. Here, any add-on could access video sync signals, the a sound signal from the audio circuit, and even a +12V line that could drive loads up to 300 mA. It just so happened the display [Quinn] is using for this project runs at 12V, 200 mA. Everything was great, but as a worthy trustee of this computer’s Earthly existence, [Quinn] thought a bit of current limiting should be included in her addon. She designed a circuit around an NPN power transistor, that would allow the display to draw power until the load was around 250mA. After that, the transistor would start dumping excess power as heat. Yes, a fuse would be better. [Quinn] calls this Fail #1. There are thirteen more to go.

Continue reading “Fail of the Week: Teddy Top and Fourteen Fails”

Fail of the Week: [Chris] vs. The Gorn

This week, [Chris] tips the scales but ultimately fails. He’s on the road, hacking through the Great White North and improvising from a poorly-lit echo chamber that happens to have a vise.

Knowing nothing about firearms (do you believe that?), he decided to build a BB cannon out of pure scrap. Several kinds of sparks fly, starting with a Hitachi drill-as-lathe and ending with a tiny cupcake sparkler. [Chris] proceeds to bore out some redi-rod by eyeballing it and offers helpful tips for course correction should you attempt same. Having centered the cavity, he drills out a tiny hole for a fuse.

His first fuse is of the crushed up match head paste variety. It burns kind of slowly and does not launch the BB. Naturally, Plan B is to make napalm glue to adhere Pyrodex pistol powder to paper. As you might imagine, it worked quite well. The wadding was singed, but still no joy. After packing her full of propellant, it still didn’t explode and merely burned out the blowhole. So, what gives? Insufficient barrel length? Should have used bamboo instead of redi-rod? Didn’t want it badly enough? Give us your fodder below.

Continue reading “Fail of the Week: [Chris] vs. The Gorn”

Fail of the Week: Sonar Submersibility Sealing

For the last decade or so, [Jason] has wanted to build an underwater robot. Can you blame him? More recently, he’s been researching sonar sensing and experimenting with the relatively inexpensive HC-SR04 module. Since he had good luck getting it to work with a PC sound card and a Stellaris Launchpad, he figured it was time to try using it underwater.

Hydrophone research led him to the idea of submerging the sensor in mineral water oil to both seal it and couple it with the water. Unfortunately, the HC-SR04 only sends one pulse and waits for echo. Through the air, it reliably and repeatedly returned a small value. Once inside a pill bottle filled with mineral oil, though, it does something pretty strange: it fluctuates between sending back a very small value and an enormous value. This behavior has him stumped, so he’s going to go back to the Launchpad unless you can help him figure out what’s going on. Should he use a different method to seal it?


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Fail of the Week: Battery Packin’

[NeXT] got himself an IBM ThinkPad TransNote and yeah, we’re pretty jealous. For the uninitiated, the TransNote was IBM’s foray into intelligent note transcription from roughly fifteen years ago. The ThinkPad doesn’t even have to be on to capture your notes because the proprietary pen has 2MB of flash memory. It won an award and everything. Not the pen, the TransNote.

Unfortunately, the battery life is poor in [NeXT]’s machine. The TransNote was (perhaps) ahead of its time. Since it didn’t last on the market very long, there isn’t a Chinese market for replacement batteries. [NeXT] decided to rebuild the replacement battery pack himself after sending it off with no luck.

The TransNote’s battery pack uses some weird, flat Samsung 103450 cells that are both expensive and rare. [NeXT] eventually found some camera batteries that have a single cell and a charge controller. He had to rearrange the wiring because the tabs were on the same side, but ultimately, they did work. He got the cells together in the right configuration, took steps to prevent shorts, and added the TransNote’s charge controller back into the circuit.

Nothing blew up, and the ThinkPad went through POST just fine. He plugged it in to charge and waited a total of 90 minutes. The charging rate was pretty lousy, though. At 94% charge, the estimated life showed 28 minutes, which is worse than before. What are your thoughts on the outcome and if it were you, what would be the next move?


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Fail of the Week: Robotic 1950 Mercury Boogies, Won’t Come Back From Dead Man’s Curve

[Dave] wanted to make an Arduino robot out of a remote-control 1950 Mercury. He removed the RC portion from the car and kept the drive and steering motors. The idea was to use three ultrasonic rangefinders in the grille real estate and move the car forward based on the longest distance detected.

He initially used a Seeed motor controller and some Grove cables soldered to his sensors to power the steering. It went forward, but only forward, and [Dave] decided the motor controller and the car’s steering motor weren’t playing well together.

[Dave] had the idea to use relays instead to both power the motor and determine polarity. Now, the Merc was turning and avoid obstacles about half the time, but it was also getting dinged up from hitting walls. He figured out that his sensor arrangement was making the car turn immediately and decided to give the program information from the wheels with a reed switch and a rare earth magnet. The only problem is that the caliber of magnet required to trip the reed switch is too heavy and strong. [Dave] and has concluded that he simply can’t exercise the kind of control over the car that he needs. and will build his own robot chassis.

Update: Check out a video of [Dave]’s car after the break.


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Continue reading “Fail of the Week: Robotic 1950 Mercury Boogies, Won’t Come Back From Dead Man’s Curve”