This pancake bipolar stepping motor from Sanyo has a 1.8° step angle (200 steps/revolution). It offers a holding torque of 2.2 kg-cm (30 oz-in), and each phase draws 1 A at 5.9 V. This stepper motor’s flat profile (21 mm including the shaft) allows it to be used in places where more traditional stepper motors would be too bulky.
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Arduino boards are able to control small motors very easily and it’s just as easy when you have to deal with controlling large motors. In the following video tutorial by NYC CNC you’ll see two examples. In the first you’ll learn how to get up and running, to start, stop, control direction and speed of a large motor with Arduino Uno. In the second example, how to use two proximity sensors as limit switches and two potentiometers to allow on-the-fly speed adjustment.
[Paul] designed a new open-hardware RNG (random number generator) that includes two sources of entropy in a small package. The first source of entropy is a typical avalanche diode circuit, which is formed by a pair of transistors. This circuit creates high-speed random pulses which are sampled by the onboard microcontroller.
What makes this design unique is a second entropy source: a CC2531 RF receiver. The RF receiver continuously skips around channels in the 2.5Ghz band and measures the RF signal level. The least-significant bit of the signal level is captured and used as a source of entropy. The firmware can be configured to use either source of entropy individually, or to combine both. The firmware also supports optionally whitening the entropy byte stream, which evens out the number of 1’s and 0’s without reducing entropy.
The OneRNG uses the USB-CDC profile, so it shows up as a virtual serial port in most modern operating systems. With the rngd daemon and a bit of configuration, the OneRNG can feed the system entropy source in Linux. [Paul] also has a good writeup about the theory behind the entropy generator which includes images of his schematic. Firmware, drivers, and hardware design files are open-source and are available for download.
Filed under: hardware
There’s a lot of spooky Pi shenanigans going on this Halloween. Here at Pi Towers, our very own Rachel Rayns is trialling the first run of the Raspberry Pi Digital Creatives Bronze award we plan to be running formally from 2015. (More of that in a later post.) Amy and Dan Mather are acting as our guinea pigs for this trial; and here are the (orange, approximately spherical) fruits of their first day’s labour.
I’ll be prodding the Mather kids for a write-up on how to rotoscope your own face onto a pumpkin soon.
A little further from home, at one of my favourite places in the UK, the team at the Lost Gardens of Heligan have made a slightly-too-successful Halloween project. People walking past this installation trigger a motion sensor, which makes a speaker up in the tree hoot in a Halloween fashion.
“Slightly-too-successful” in this instance means that at twilight, visitors walking past triggered the audio: and real, female tawny owls responded to it, and were attracted to the tree. Which is great for owl-spotters, but a bit unfair on the owls. So the Heligan team swapped out the audio for the blood-curdling howls of a wolf (not native to Cornwall), and all was well again. You can read more about the project over at our friend Phil Atkin’s blog.
Further afield, Cabe Atwell in the USA has a haunted porch. (Careful watching this one if you have small children in the room – it’s a bit unsettling.)
There’s a lot of how-to detail in Cabe’s video, and a full write-up over at element14.
Back in the UK, Halloween’s being used as a teaching tool by TeCoEd.
Here’s a how-to video, and you’ll find everything you need to make one yourself next year at TeCoEd’s website.
You’ll find plenty more projects from previous years under the Halloween tag. Have you made something spooky with a Pi this year? Let us know in the comments!
A new episode of Electricute, plus some changes on the wind!
That’s right- it’s not just a new episode of ElectriCute, though we’re very proud of this one, we’re also making some changes!
Here are a few changes you WON’T be seeing:
- I won’t be leaving
- Nick won’t be leaving
- Still no sock puppets
- No additional ASMR triggers* (but we won’t remove any of the existing ones)
And a few that you WILL:
- More frequency! Breaktime is OVER, people! We’ll be cranking out several videos a month now.
- More frequency means we’ll get a lot deeper in the catalog, so you’ll see a lot more information about integrating products from outside the e-textiles category into your wearables products.
- What does that mean? More sensors! More interactivity! More complex projects!
- Why isn’t that scary? Because you’ll also be getting a lot more accompanying tutorials! Need more details on how we put something together? You’ll get ‘em.
- We’re going to be more responsive to your questions and suggestions. Post your questions or product requests in the comments, and we’ll work on replying to them, either there or in the next video!
So with no further ado, here’s this week’s video! Feast your eyes, check out the accompanying tutorial, and get ready to talk about the bad old days when you had to simulate your own ElectriCute episodes by giving your pets squeaky voices!
*Unless video views drop below an undefined threshold, at which time we’ll try basically anything
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.
Filed under: hardware
The good people at Adafruit pointed us at this video. Besides the fact that the costume is driven by a Raspberry Pi, we don’t know much about the build (or the guy who made it – he goes by MikeHandidate on YouTube, but we suspect that’s not actually his name) – good though, isn’t it?
More Halloween goodies to come tomorrow. Are you using a Pi in your costume or house decorations this year?
Eva Taylor works at EKT Workshop and built an animatronic rod puppet Alien as a masterwork research project for the National Institute of Dramatic Art (NIDA) in Sydney Australia. It was inspired by the “bambi burster” built for the film Alien 3, although her creature is somewhat different.
The animatronics are controlled via a Playstation 3 controller, using a servoshock module between the controller and an Arduino Uno board:
It contains and 8 way 2 stage tail mechanism and animatronic lips, jaw and tongue. The remaining parts are rod controlled. A myriad of techniques were deployed in its construction – the torso and limbs were hand-carved from Queensland Maple while the joints were custom made from recycled parts of RC cars and planes. The skeleton of the tail was custom made from acrylic and cut on a laser cutter. The head contains an underskull of fibreglass, dental acrylic teeth and silicone skin. The muscle groups are also made of deadened, encapsulated silicone.
She shared with us the video above showing the main phases of the making-of process, while the one below gives you an idea of how the puppet looks like in a more dramatic piece: