An ATTiny Bluetooth Board

Since just about everyone who would be interested in electronics has a decent cellphone now, there’s an idea that we don’t need USB or weird serial adapters anymore. Bluetooth LE is good enough for short-range communication, and there are a ton of boards and Kickstarter projects out there that are ready to fill the need.

[Michah] has built what is probably the lowest-spec and cheapest BTLE board we’ve ever seen. It’s really just an ATTiny85 – a favorite of the crowd that’s just slightly above Arduino level – and an HM-10 Bluetooth 4.0 Low Energy module.

This board was developed as a means to connect sensors for a vintage motorcycle to an iOS device for display and data logging. A small, cheap board was needed that could be powered by a LiPo battery, and [Micah] created a board that fit his needs perfectly.

Four of the six IO pins on the ‘Tiny85 are broken out on a pin header; two are used to communicate with the BTLE module. It’s simple, fairly cheap, and can be powered by a battery. Exactly what you need if you want a wireless sensor board. All the files can be found in the Git repo and everything is open source. Not bad.

Reverse Engineering a Blu-ray Drive for Laser Graffiti

There’s a whole lot of interesting mechanics, optics, and electronics inside a Blu-ray drive, and [scanlime] a.k.a. [Micah Scott] thinks those bits can be reused for some interesting project. [Micah] is reverse engineering one of these drives, with the goal of turning it into a source of cheap, open source holograms and laser installations – something these devices were never meant to do. This means reverse engineering the 3 CPUs inside an external Blu-ray drive, making sense of the firmware, and making this drive do whatever [Micah] wants.

When the idea of reverse engineering a Blu-ray drive struck [Micah], she hopped on Amazon and found the most popular drive out there. It turns out, this is an excellent drive to reverse engineer – there are multiple firmware updates for this drive, an excellent source for the raw data that would be required to reverse engineer it.

[Micah]’s first effort to reverse engineer the drive seems a little bit odd; she turned the firmware image into a black and white graphic. Figuring out exactly what’s happening in the firmware with that is a fool’s errand, but by looking at the pure black and pure white parts of the graphic, [Micah] was able guess where the bootloader was, and how the firmware image is segmented. In other parts of the code, [Micah] saw thing vertical lines she recognized as ARM code. In another section, thin horizontal black bands revealed code for an 8051. These lines are only a product of how each architecture accesses code, and really only something [Micah] recognizes from doing this a few times before.

The current state of the project is a backdoor that is able to upload new firmware to the drive. It’s in no way a complete project; only the memory for the ARM processor is running new code, and [Micah] still has no idea what’s going on inside some of the other chips. Still, it’s a start, and the beginning of an open source firmware for a Blu-ray drive.

While [Micah] want’s to use these Blu-ray drives for laser graffiti, there are a number of other slightly more useful reasons for the build. With a DVD drive, you can hold a red blood cell in suspension, or use the laser inside to make graphene. Video below.

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Building A Better Sewing Machine

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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The story behind developing the Sifteo from an engineer’s perspective

how-the-sifteo-was-developed

The video game industry must be one of the most secretive sectors when it comes to developing the electronic hardware used in the gaming consoles. The big guys don’t want to give anything away — to the competition or to the hackers who will try to get around their security measures. But it seems Sifteo doesn’t share those secretive values. We had a great time reading about the bumpy ride for the developers bringing the gaming system from concept to market. [Micah Elizabeth Scott] wrote the guest post for Adafruit Industries. She was brought on as an engineer for the Sifteo project just after the first version of the interactive gaming cube was released. From her narrative it seems like this was the top of the big hill on the roller coaster ride for the company.

What’s seen above is one gaming cube. The system developed in [Beth’s] story puts together multiple cubes for each game. The issue at hand when she joined the company was how to put more power in the hardware and rely less heavily on a computer to which it was tethered. She discusses cost of components versus features offered, how to deliver the games to the system, and all that the team learned from studying successful consoles that came before them like the long line of Nintendo hardware. It’s a fascinating read if you’re interesting in how the sausage is made.

Reproduce 3D printed models by making your own molds

Need fifty copies of that 3D printed whirligig you’re so proud of? It might be faster to just cast copies by using the 3D printed model to make a mold. [Micah] found himself in this situation and managed to cast one copy every 10-12 minutes using the mold seen above.

With the object in hand, you need to find a container which will fit the mold without too much waste. The bottom half of the mold is then filled with modeling clay, a few uniquely shaped objects to act as keys, and the model itself. After getting a good coating of release agent the rest of the mold is filled with a silicone rubber product which is sold for mold making. This creates one half of the mold. After it cures the clay and key objects are removed, everything is sprayed with the release agent, and the other half of the mold is poured.

Now your 3D object can be copied by pouring two-part resins in the to shiny new mold.

USB host for Propeller micros

[Micah Dowty] has implemented full speed USB host control on a Propeller microcontroller. He’s motivated by the thought of using USB based WiFi and Bluetooth dongles in his projects as ready-made solutions.We’ve seen USB host control with the Arduino and it really opens up the flood gates for advancing your projects through storage, wireless connectivity, and user interface.

So far his work is fairly preliminary but the results seen from other participants in the Parallax forums are very positive. Check out his code from the subversion repository and lend a hand with the development.

[Thanks Stefan via Adafruit]

Hacking a digital bathroom scale

[Micah] was inspired by projects he had seen of people using the Wii balance board as an input. He realized the balance board was overkill, and pricey for many applications. Since it is basically just 4 weight sensors, he thought, why not just use a scale? Often, only one sensor is needed and they’re really cheap from big box stores. He picked up a digital scale and cracked it open. As he moved forward, he wanted to keep this pretty simple. There are other ways of getting the information from a scale, but they have been generally more complicated than what he had in mind. He ended up bypassing the internal unknown microcontroller and just connecting the analog sensors to his parallax setup. You can read all about the process an download some source code on his site.

[via Flickr]