Building A Better Sewing Machine

February 16, 2014 by 16 Comments

sewing

After making a few fabric RFID tags, [Micah] had a sewing machine sitting in her workshop completely unused. This was due at least in part to how crappy this entry-level sewing machine was; it stalled easily, unusable at low speeds, and noises like a robot with bronchitis. The solution, of course, was to replace the motor and add electronic control, turning a terrible sewing machine into one that should cost several hundred dollars more.

After some experimentations with an AC motor, [Micah] came upon a small DC motor. This, combined with an LMD18200 H-bridge, Propeller microcontroller, and a beefy power supply gave [Micah] enough torque to run the sewing machine without mechanical wheezing and grinding.

The new update to the motor allowed [Micah] several control modes for the machine, all controlled by the foot pedal: an open-loop mode is pretty much the same as the stock machine, a closed-loop mode keeps a constant RPM on the motor regardless of resistance. There are a few more interesting modes that moves the needle down when the pedal is released, perfect for detailed work.

A small addition to this project was an LCD attached to the front of the machine, allowing [Micah] to toggle modes without the microcontroller being connected to the computer.

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Fixing The Unfixable: Pebble Smartwatch Screen Replacement

February 16, 2014 by 16 Comments

[Colt] found himself with a broken Pebble, so he fixed it. The Pebble watch really ignited the smartwatch world with its record-breaking Kickstarter campaign. Working on the Pebble has proved to be frustrating experience for hardware hackers though. Ifixit’s teardown revealed the Pebble extremely difficult to repair. This isn’t due to some evil plan by the smartwatch gods to keep us from repairing our toys. It’s a problem that comes from stuffing a lot electronics into a small waterproof package. [Colt’s] problem was a bad screen. Pebble has a few known screen issues with their early models. Blinking screens, snow, and outright failed screens seemed to happen at an alarming rate as the early Kickstarter editions landed. Thankfully all those issues were corrected and replacements sent to the unlucky owners.

The actual screen used in the Pebble is a Sharp Memory LCD. Memory is an apt name as the screens actually behave as a SPI attached write only memory. Sharp sells flexible printed circuit (FPC) versions of the LCDs to aid in debugging. For space constrained designs though, an elastomeric or “zebra strip” connector is the common way to go. Alternating bands of conductive and insulating material make electrical connections between the Pebble’s circuit board and the conductive portions of the LCD glass.

[Colt] found himself with a dead screen out of warranty, so he decided to attempt a screen replacement. He found a replacement screen from Mouser, and proceeded to remove the top case of his watch. The top plastic case seems to be the hardest part of getting into a Pebble. It appears to be bonded with a glue that is stronger than the plastic itself. [Colt] broke the glass of his screen during the removal, which wasn’t a big deal as it was already dead. Prying only destroyed the top plastic, so he broke out a rotary tool which made quick work of the plastic.  The new screen worked perfectly, but had to be held in just the right position over its zebra connector. Some waterproof epoxy held it in place permanently. The next step was a new top cover. An old flip phone donated its plastic shell to the effort, and hot glue kept everything in place. [Colt] finished his work with a couple of layers of model paint. The result certainly isn’t as pretty or waterproof as the original. It is functional though, and about $120 USD cheaper than buying a new Pebble.

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Nrf24l01+ Using 3 ATtiny85 Pins

February 16, 2014 by 15 Comments

[Ralph] wasn’t satisfied with the required 5 control pins to drive his nrf24l01+ transceiver module, so he used this circuit needing just 3 pin using an ATtiny85.

One of the key components was to effectively drive the chip select (CSN) line from the clock (SCK) line. The nrf24l01+ needs the CSN line to transition from high to low on the beginning of a communication.  [Ralph] put the SCK line behind a diode, put a capacitor in parallel with the CSN line and altered the arduino-nrf24l01 library to encode extra delays for the clock line.  This allowed the CSN line to be driven by the SCK line. Subsequent line transitions during transmission happen too fast to charge the capacitor, leaving the CSN line in a low state.

After tying the chip enable line high and dropping the 5V power line to 1.9-3.6V across a red LED, [Ralph] had an ATtiny85 controlling a nrf24l01+ module.

Though deceptively simple, a very cool hack that opens up a couple more lines on the ATtiny85.

ReSCan — Automated Resistor Identification!

February 16, 2014 by 59 Comments

Need a quick and easy way to sort through a few hundred random resistors? You could do them one at a time by reading the color codes yourself… or you could get a machine to do it for you!

When [Robert] was faced with a pile of unsorted resistors he quickly decided he did not have the patience to sort them manually. So, he started by writing an Android app using OpenCV to detect and identify resistor color codes. The problem is, most phones have trouble focusing at short distances — and since resistors are so small, holding the phone farther back results in color rings only being a few pixels wide — not the greatest for image recognition!

So, he started again on his computer, using a cheap LED-lit webcam instead. He wrote the app in java so he could re-use parts of the code from the Android app. It seems to work pretty well — check it out in the following video! This would be perfect to pair up with your illuminated storage bin hack.

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Hacking A DVD Recorder

February 16, 2014 by 20 Comments

Hacked DVD Recorder

[w00fer] wanted to see if any modifications to a DVD Recorder were possible. Initially, the goal was to upgrade the internal hard drive for additional storage. However, after cracking open a DVDR3570H and finding a service port, he decided to look a bit deeper.

Connecting an RS232 to USB converter to the service port resulted in garbled data. It turned out that the port was using TTL signal levels instead of RS232 levels. This was solved by building a converter using the MAX232 converter IC.

With the converter in place, the service menu appeared. It performs some tests and spits out the results when the device is booted. After that, it sits at a prompt and waits for commands. Fortunately, [w00fer] found the service manual which lists the available commands. So far, he’s been able to generate test patterns, test lights, change the display text, spin up the hard drive, and read device information. However, the next steps include disabling Macrovision copy protection, dumping the EEPROM and NVRAM, and copying data off of the hard drive. If you think you can help [w00fer] out, let him know.

Ion Propelled Tie Fighter Now Has A Laser!

February 15, 2014 by 9 Comments

ion

[Steven Dufresne] has been playing around with ion propulsion using high voltage lately, and he’s added another spaceship to his experiments — Darth Vader’s TIE Fighter — and as an added bonus, he’s thrown on a laser too!

We originally covered his Ion Wind Propelled Star Trek Enterprise a few months ago, after someone had mentioned that the ion winds he was generating in experiments kind of looked like the warp drives on the Enterprise. Well, someone else pointed out that a TIE Fighter was an even better candidate for this. After all, TIE stands for Twin Ion Engines. So he decided to build one too. The ion winds look even better on this one as he’s turned the entire back of the fighter into the electrode, which creates a wide and very visible arc.

Oh, he also decided to add lasers to it for some extra flare — unfortunately TIE Fighters used green lasers — not red ones. Stick around for the following videos to see the TIE Fighter in all its ionic glory.

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SMD Soldering On… Hot Sand?

February 15, 2014 by 26 Comments

Need to do some SMD soldering? No tools? No problem! Here’s a creative method that could be a handy tool to add to your belt: SMD soldering using hot sand.

[Oliver Krohn] recently released this little video demonstrating how to perform re-flow soldering using hot sand. He’s using a bunsen burner to heat up a ceramic pot of sand to use as a kind of hot plate. It seems to work pretty well, and it’s a very unique way of doing it — if you wanted to get a bit more technical, you could also throw a temperature probe in the sand to get a much finer heat control!

Of course there are lots of other ways of doing re-flow soldering, like using a re-purposed toaster oven, frying up some circuits on a skillet after you’ve had your bacon, or if you want to be fancy, you could even build your own toolkit for it!

Anyway, stick around for the epic video of SMD soldering on hot sand.

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