One of our avid readers named [Felix] suffers from sleep apnea, and needs a CPAP machine in order to not suffocate while he sleeps — After a recent power-outage, his machine broke, so he decided to try his hand at fixing it.
A CPAP (Continuous Positive Airway Pressure) machine ensures people suffering from sleep apnea breath throughout the night, by preventing their throats from closing. As a medical device, they tend to be super expensive, which is why [Felix] wanted to try fixing his (at least until he gets a new machine covered by insurance).
Upon opening up the machine, it was easy to see the problem: the circuit board was completely fried. Luckily, the machine is pretty simple. It has a brushless DC motor (12V), and two chambers with air filters, along with an air pressure sensor. Since the motor is brushless, it’s not quite as simple as just hooking it up to a power supply. It had a whopping 8 separate leads.
Jacob’s Ladders are a staple experiment in any self-respecting mad scientist’s lair — err, a hacker’s workshop. And why not? High voltage, arcing electricity, likely more than enough to kill you even — brilliant! But in all their awesomeness, Jacob’s ladders really aren’t that complex.
In [Kevin Darrah’s] latest tutorial he shows us how to make one out of a transformer taken from an oil furnace. Why exactly does an oil furnace even have a high voltage transformer in the first place? They’re actually used as the ignition source, like a pilot light!
The one [Kevin] has is a 110VAC to 10,000VAC transformer, which puts out about 20mA (probably enough to kill you). And to turn it into a Jacob’s Ladder, you’ll just need a two long stiff wires (copper is a good candidate). The wires are closest at the bottom where the transformer can easily arc — this arc then ionizes and heats the air causing it to rise, carrying the arc with it. As the arc continues up the ladder it gets longer and longer as the wires become farther apart, becoming more and more unstable until it breaks. When this happens the arc forms again at the lowest point of resistance — the bottom.
You probably remember that for DEFCON I built a hat that was turned into a game. In addition to scrolling messages on an LED marquee there was a WiFi router hidden inside the hat. Get on the AP, load any webpage, and you would be confronted with a scoreboard, as well as a list of usernames and their accompanying password hashes. Crack a hash and you can put yourself on the scoreboard as well as push custom messages to the hat itself.
Choosing the complexity of these password hashes was quite a challenge. How do you make them hackable without being so simple that they would be immediately cracked? I suppose I did okay with this because one hacker (who prefers not to be named) caught me literally on my way out of the conference for the last time. He had snagged the hashes earlier in the weekend and worked feverishly to crack the code. More details on the process are available after the jump.
[Enzo] wrote in to tell us about his recently completed CNC Router (translated). This is an excellent high-quality, all-aluminum build with no cut corners. The work envelope is a respectable 340 by 420 mm with 80 mm in the Z direction. Linear ball bearings make for smooth travel and lead screws with both axial and radial bearings give a solid foundation of accurate and repeatable movements.
We’ve had a bunch of CNC Router projects on Hackaday in the past, including other nicely made aluminum ones, but [Enzo] is the only one who spent just as much effort on his computer and machine control system as he did on the CNC machine itself. The computer, which is running Windows and Mach3, is an all-in-one style build that starts out with an old LCD screen from a broken laptop. Along with the reused screen, a very small ETX form factor motherboard was stuffed inside a custom made plexiglass enclosure. A Compact Flash card handles the storage requirements.
Underneath the monitor is another great looking custom made enclosure which houses the stepper motor drivers. There are 3 switches on the front panel to send main’s power out to the PC, spindle and an AUX for future use. On the back panel there are D-sub connectors for each stepper motor, the limit switches and the PC connection. Oh yeah, by the way [Enzo] designed his own bipolar motor drivers (translated) and sent the design out for fabrication. These boards use an A4989 IC and mosfets to control the motors. The schematics are on his site in case you’d like to make some yourself.
Everyone has a bad day right? Monday was a particularly bad day for the folks at Sparkfun. Customer support tickets started piling up, leading to the discovery that they had shipped out as many as 1,934 MicroViews without bootloaders.
MicroView is the tiny OLED enabled, Arduino based, microcontroller system which had a wildly successful Kickstarter campaign earlier this year. [Marcus Schappi], the project creator, partnered up with SparkFun to get the MicroViews manufactured and shipped out to backers. This wasn’t a decision made on a whim, Sparkfun had proven themselves by fulfilling over 11,000 Makey Makey boards to backers of that campaign.
Rather than downplay the issue, Sparkfun CEO [Nathan Seidle] has taken to the company blog to explain what happened, how it happened, and what they’re going to do to make it right for their customers. This positions them as the subject of our Fail of the Week column where we commiserate instead of criticize.
First things first, anyone who receives an affected MicroView is getting a second working unit shipped out by the beginning of November. Furthermore, the bootloaderless units can be brought to life relatively easily. [Nate] provided a hex file with the correct bootloader. Anyone with an Atmel AVR In-System Programming (ISP) programmer and a steady hand can bring their MicroView to life. Several users have already done just that. The bootloader only has to be flashed via ISP once. After that, the MicroView will communicate via USB to a host PC. Sparkfun will publish a full tutorial in a few weeks.
Click past the break to read the rest of the story.
My introduction to electronic manufacturing was as a production technician at Pennsylvania Scale Company in Leola PA in the early 1980’s. I learned that to work on what I wanted to work on I had to get my assigned duties done by noon or thereabouts. The most important lesson I had learned as a TV repairman, other than not to chew on the high voltage cable, was to use your eyes first. I would take a box of bad PCB’s that were essentially 6502 based computers that could count and weigh, and first go through inspecting them; usually the contents were reduced 50% right off by doing this. Then it was a race to identify and fix the remaining units and to keep my pace up I had to do my own desoldering.
It worked like this; you could set units aside with instructions and the production people would at some point go through changing components etc. for you or you could desolder yourself. I was pretty good at hand de-soldering 28 and 40 pin chips using a venerable Soldapulit manual solder sucker (as they were known). But to really cook I would wait for a moment when the production de-soldering machine was available. There was one simple rule for using the desoldering station: clean it when done! Failure to do so would result in your access to the station being suspended and then you might also incur the “wrath of production” which was not limited to your lunch bag being found frozen solid or your chair soaked in defluxing chemicals.
This isn’t one of those clean retrocomputers with every connection carefully planned out and wire wrapped. [Peter’s] created a true hack – a working 68k system on a breadboard created with whatever he had on hand at the time. The real gem of this system is the ROM. [Peter] replaced an EPROM chip with an Arduino.
In the not-so-good-old-days, microprocessors (and many microcontrollers) ran from an external ROM chip. This often was a UV-erasable EPROM. Carefully compiled code was burned into the EPROM with a device programmer. If the code wasn’t perfect, the EPROM had to be pulled and placed under a UV lamp for 20 minutes or so to erase it before it was time to try again. EPROM emulators were available, but they were way too expensive for the hobbyist.
Thankfully those days are far behind us now with the advent of EEPROM and then Flash. [Peter] didn’t want to revisit the past either, so he wrote a simple Arduino sketch which allowed it to act as an EPROM emulator, including address logging via the serial port.
The design still caused [Peter] some headaches, though. His major problem was a classic 68k issue, /DTACK timing. /DTACK or Data Transfer Acknowledge is one of several bus control signals used by the 68k. When the 68k performs a read from the data bus, it waits for /DTACK before it transfers data. The Arduino was too slow to release /DTACK in this case, which caused the 68k to think every read was immediately completed. There is a much clearer explanation of the 68k bus cycles on this Big Mess O Wires page. [Peter’s] solution was simple – a D flip-flop connected to the address strobe took care of the timing issues.
It took quite a bit of tinkering, but the system eventually worked. Peter was able to run the 68008 from its reset vector into a simple loop using the Arduino. It’s only fitting that the 68k program loaded by the Arduino was an LED blinker, everyone’s favorite hardware Hello World.