Hacklet 124 Running Robots And The Claw

September 10, 2016 by Adam Fabio 14 Comments

You never know what you’ll find when you open the projects feed on Hackaday.io. Most weeks, The Hacklet follows a theme of some sort. Sometimes I find projects that just look so cool that I have to get the word out about them.

Such is the case with this week’s first project, Mr. Runner created by [Alex Martin]. Mr. Runner is a quadruped robot that really looks the part. In fact, I’d say it looks like it’s ready to jump off the bench top. Like many of us, [Alex] has been inspired by Boston Dynamics, specifically their Wildcat robot. Wildcat had [Alex] searching the net for walking robot designs. He struck up something he liked with the work of [Dr. Fumiya Iida] and [Dr. Rolf Pfiefer]. In the mid 2000’s, the pair worked out of the University of Zurich. Mr. Runner is based upon their work, with plenty of design tweaks from [Alex].

The basic design is a quadruped with two servos per leg. The servos are at the body and the upper half of the leg. The knee and lower leg are connected by levers and a spring, forming something of a 4 bar linkage. The spring acts as a tendon, absorbing shock, and allowing energy from the servo to be stored and released while the robot runs. [Alex] is experimenting with gaits, controlled by a PC.

Mr. Runner wouldn’t be doing much running without a way to control those 8 servos. [Alex] started with an Arduino and a LynxMotion serial servo controller. This pairing served him well for the first generation of Mr. Runner. For the new version of the robot, he’s rolling his own board based upon Lynxmotion’s
BotBoarduino. The Gerber files have been sent off to OSH Park, and in about a week, Mr. Runner will be off to the races.

Another great recently updated project is Arcade Claw Game Claw Build by [Alex Anderson]. I spent way too many hours of my youth in arcades, and more than a few quarters went into claw games. Sure, they’re usually rigged, but who hasn’t been pulled in by the chance to test your skill and win a prize? A friend asked [Alex] to design an arcade style claw for a game. A seasoned CNC and 3D printing master, [Alex] grabbed his notebook and started sketching. Rack and pinion designs would work well, but didn’t within the constraints of the game. A leadscrew based design would also work, but would be two expensive. Finally, [Alex] settled on a design and fired up his CAD software. He started with two jaw systems to prove out the basic system. Once that was complete, [Alex] moved to a 4 jaw setup.

Much like the arcade games, the claw is actuated by a central plunger. The plunger drives linkages which move the 4 claw jaws. Everything looks good on paper, but when the CAD drawings meet the real world, things get complicated quickly. The initial design relied on a 3D printed part which connected the plunger to the jaw linkages. Any slop in this part would be magnified through the rest of the mechanical system. 3D printers aren’t perfect, and there was some slop — enough that the parts would pinch and bind up while moving.

[Alex] already has a revised design in mind. This is very much a work in progress. That’s the beauty of well documented projects on Hackaday.io — you get to see what works, as well as all the trials and tribulations it took to get to a final working project. Keep at it [Alex], you’re almost there!

That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 123 – Watches

September 3, 2016 by Adam Fabio 22 Comments

Time and tide wait for no man. Chaucer may be right, but a man (or woman) wearing a watch can get ahead of time before it sneaks up on them. People aren’t ever satisfied with just the time though. They want the date, the phase of the moon. [Woz] summed it up pretty well when he said “I want the entire smartphone, the entire Internet, on my wrist”. Hackers love watches too, which means there are plenty of watch projects out there. Some of them even tell time. This week we’re looking at some of the best watch projects on Hackaday.io!

We start with [Max.K] and Chronio. You might think Chronio looks a bit like the Pebble Time, and you’d be right! [Max] based his design heavily on Pebble’s case design. Pebble even has their CAD files on GitHub, which helped [Max] with his modified, 3D printed version. Chronio is Arduino based, using an ATmega328p microcontroller with the Arduino bootloader. The display is Sharp’s 96×96 pixel Memory LCD. A DS3231 keeps the time accurate, and provides a free temperature sensor. The entire watch is powered by a CR2025 battery. Running a 20uA sleep current, [Max] estimates this watch will last about 6 months on a single battery.

Next we have [Joshua Snyder] and Neopixel pocket watch. Who said a watch has to go on your wrist? [Joshua] brings some steampunk style to the party. His watch uses an Adafruit 12 NeoPixel ring to tell time. Red, blue, and green LEDS represent the hour, minute and second hands. The watch is controlled by an ESP8266. The time is set via WiFi. Between the LEDs and the power-hungry ESP8266, this isn’t exactly a low-power design. A 150mAh LiPo battery should keep things running for a few hours though. That’s more than enough time to make a splash at the next hackerspace event.

Next up is [ipaq3115] and The Pi Watch. Round smartwatches have created a market for round LCD screens. These screens have started to trickle down into the hacker/maker market. [ipaq3115] got his hands on one, and had to design something cool with it. The Pi Watch isn’t powered by a Raspberry Pi, but a Teensy 3.1. [ipaq3115] included the Freescale/NXP Kinetis processor and MINI54 bootloader chip on his own custom board. He used the Teensy’s analog inputs to create his own 10 element capacitive touch ring. This watch even has a LSM303 magnetometer/accelerometer. All this power comes at a cost though. It takes a 480 mAh LiPo battery to keep The Pi Watch Ticking.

Finally we have [Vikas V] and ScrolLED watch. Who says a watch has to have an LCD? [Vikas V] wanted a scrolling LED display on his wrist, so he built his own. An Atmel ATmega88V-10AU controls a 16×5 charlieplexed LED array. [Vikas] included a character font with many of the ASCII symbols in flash, so this watch can display messages. Power comes from a CR2032 watch battery in a custom PCB mounted holder. [Vikas] biggest issue so far has been light leaks from LED to LED. He’s considering mounting the array on the bottom of the watch. Shining the LEDs up through holes in the PCB would definitely help with the light leakage.

If you want to see more watch projects, check out our new watch projects list. Notice a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 122 – Spectrometers

August 27, 2016 by Adam Fabio 6 Comments

There is always something interesting to find when browsing the projects on Hackaday.io. I’m always amazed at how much hackers can get done in their basements and home labs. One surprising trend I’ve found is the sheer number of spectrometer projects people across the globe are working on. I’ve always known what a spectrometer is, but I never knew so many hackers would want them. The numbers don’t lie though – plenty of hackers around the world want to measure the spectra of light — be it to test out a new LED, or determine the structure of an object. This week we’re checking out some of the best spectrometer projects on Hackaday.io!

We start with [fl@C@] and ramanPi – Raman Spectrometer. RamanPi is one of the first spectrometer projects on Hackaday.io. [fl@C@] entered his project in the 2014 Hackaday Prize, and was one of 5 finalists. As the name implies, ramanPi is a raman spectrometer, a type often used in chemistry. [fl@C@’s] original use for the machine was determining atomic bond angles. RamanPi uses 3D printed parts created with standard desktop printers wherever possible. A Raspberry Pi runs the system, originally a model B, though now I’m sure a Pi 3 would fit the bill. The detector is a Toshiba linear CCD.

Next up is [David H Haffner Sr] with DH 4.0 Spectrometer V 4 ( upgrade 2 ). [David’s] project doesn’t give a lot of background in the description text – he dives right in to the technical details of designing and building a spectrometer. His sensor is a JDEPC-OV04, which is a webcam module intended for use in laptops. Much of [David’s] recent work has been on the optical path. Optical spectrometers can use a diffraction grating and a slit to split light into spectra. [David] is using a recordable DVD as his diffraction grating. The slit is a bit more home-made. Two Gillette razor blades and an acetate strip are used to form an optical slit only 0.11 mm wide. [David] has already used his spectrometer to analyze crude oil.

Next we have [Pure Engineering] with C12666MA Micro-Spectrometer. Electro-Optics manufacturer Hamamatsu has created an optical spectrometer in a fingertip sized can. Their C12666MA micro-spectrometer sounds like it must be magic — and it is. The magic of Microelectromechanical systems (MEMS) have brought this device to life. Bringing one of these devices up isn’t exactly an easy task though. [Pure Engineering] has designed a breakout board for the C12666MA. They’ve even included a 404nm laser diode and a white LED for illumination. The board can plug into a standard Arduino header.

Finally, we have [Adam] with Handheld VNIR Spectrometer. VNIR in this case stands for visible and near-infrared. [Adam] created this device so he could learn how spectrometers worked. That’s a noble purpose if I ever heard one. He is building his system to be portable, so he can take measurements outside the lab. The sensor is a Sony ILX511B linear CCD. An Arduino nano reads the CCD and passes the data on to a PC for analysis. [Adam’s] diffraction grating is a concave holographic affair from Public Lab. [Adam] is also using an acetate slit purchased from Public Lab. Illumination enters via a fiber optic bundle.

If you want to see more spectrometer projects, check out our new spectrometer projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Interactive Dynamic Video

August 26, 2016 by Adam Fabio 12 Comments

If a picture is worth a thousand words, a video must be worth millions. However, computers still aren’t very good at analyzing video. Machine vision software like OpenCV can do certain tasks like facial recognition quite well. But current software isn’t good at determining the physical nature of the objects being filmed. [Abe Davis, Justin G. Chen, and Fredo Durand] are members of the MIT Computer Science and Artificial Intelligence Laboratory. They’re working toward a method of determining the structure of an object based upon the object’s motion in a video.

The technique relies on vibrations which can be captured by a typical 30 or 60 Frames Per Second (fps) camera. Here’s how it works: A locked down camera is used to image an object. The object is moved due to wind, or someone banging on it, or any other mechanical means. This movement is captured on video. The team’s software then analyzes the video to see exactly where the object moved, and how much it moved. Complex objects can have many vibration modes. The wire frame figure used in the video is a great example. The hands of the figure will vibrate more than the figure’s feet. The software uses this information to construct a rudimentary model of the object being filmed. It then allows the user to interact with the object by clicking and dragging with a mouse. Dragging the hands will produce more movement than dragging the feet.

The results aren’t perfect – they remind us of computer animated objects from just a few years ago. However, this is very promising. These aren’t textured wire frames created in 3D modeling software. The models and skeletons were created automatically using software analysis. The team’s research paper (PDF link) contains all the details of their research. Check it out, and check out the video after the break.

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Books You Should Read: The Soul Of A New Machine

August 26, 2016 by Adam Fabio 47 Comments

If there was one book that describes what it means to be in the trenches of a cutting edge design, that book is The Soul Of a New Machine. Tracy Kidder’s Pulitzer prize-winning book has been an inspiration to thousands over the years.

Soul is the story of the creation of the Data General Eclipse MV/8000, code-named Eagle. Eagle was Data General’s first 32-bit minicomputer. If you’re not a retrocomputing aficionado, minicomputers were a major industry back in the 70’s and 80’s. Starting in 1964 with the Digital Equipment Corporation (DEC) PDP-8, minis provided a low-cost means for companies to get a computer. The only other option was a huge mainframe from companies like IBM. Minicomputers chugged along until the 1990s when microprocessor-based PCs and workstations passed them by. The market, and the industry evaporated.

Today, more than 30 years later, minicomputers are all but forgotten. Data General itself is long gone, purchased by EMC in 1999. DG’s mark on the landscape has all but been erased by the swiftly moving sands of technical progress. All except for the snapshot Kidder set down in Soul.

An MV/8000 installation (from DG literature)

The technical side of designing a new computer is just one part of this book. The Soul of a New Machine is three stories: the story of the engineers, the story of the managers, and the story of the machine they built. For this reason, the book has found itself on the reading list of engineering schools and management institutes alike.

The thing that makes this book appeal to the masses is Kidder’s uncanny ability to explain incredibly complex topics in layman’s terms. He manages to explain the inner workings of a 32-bit CPU, all the way down to the level of microcode. He delves into Programmable Array Logic (PALs), forerunners of the CPLD and FPGA devices you read about on our pages today. PALs were a hot new technology back in the late 70’s. They allowed the Eagle team to make changes quickly — without pulling out their wire wrapping tools.

Kidder manages to explain these things in a way that doesn’t leave the average Joe scratching their head, yet doesn’t bore the technically savvy. If he ever decides to stop writing non-fiction, Tracy Kidder would have a career writing user manuals.

The Soul of a New Machine starts in a very unlikely place – on the deck of a sailing ship during a rough storm. The scene is our introduction to the star of the book – Tom West, a manager at Data General. West is multifaceted and enigmatic to say the least. A folk guitarist who was inspired to work on electronics by the Apollo program. He was a few years too late for NASA though. Eventually he found himself travelling the world building and adjusting incredibly accurate clocks at astronomical observatories for the Smithsonian. This meandering path eventually led him to DG, where he was hired as a computer engineer and quickly worked his way up the ranks.

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A Refrigerator Cooled By Rubber Bands

August 25, 2016 by Adam Fabio 35 Comments

Ever noticed that a rubber band gets warmer when it’s stretched? The bands also get cooler when allowed to snap back to relaxed length? [Ben Krasnow] noticed, and he built a rubber band cooled refrigerator to demonstrate the concept. The idea of stretching a rubber band to make it hotter, then releasing it to make it cooler seems a bit counter intuitive. Normally when things get smaller (like a gas being compressed) they get hotter. When pressure is released the gas gets cooler. Rubber bands do the exact opposite. Stretching a rubber band makes it hot. Releasing the stretched band causes it to get cooler.

No, the second law of thermodynamics isn’t in jeopardy. The secret is in the molecular structure of rubber bands. The bands are made of long polymer chains. A relaxed rubber band’s chains are a tangled mess. Stretching the band causes the chains to untangle and line up in an orderly fashion. By stretching the band you are decreasing its entropy. The energy of the molecules in the band don’t change, but entropy does. All the work one does to stretch the band has to go somewhere, and that somewhere is heat. This is all an example of entropic force. For a physics model of what’s going on, check out ideal chains. If you’re confused, watch the video. [Ben] does a better job of explaining entropic force visually than we can with text.

To test this phenomenon out, [Ben] first built a wheel with rubber bands as spokes. Placing the wheel in front of a heater caused it to slowly rotate. [Ben] then reversed the process by building a refrigerator. He modeled his parts in solidworks, then cut parts with his Shaper handheld CNC. The fridge itself consists of an offset wheel of rubber bands. The bands are stretched outside the fridge, and released inside. Two fans help transfer the thermal energy from the bands to the air. The whole thing is hand cranked, so this would make a perfect museum or educational demonstration. Cranking the fridge for 5 minutes did get the air inside a couple of degrees cooler. Rubber is never going to displace standard refrigerants, but this is a great demo of the principles of entropic force.

For more thermodynamic fun, check out [Al Williams] recent article about building a DIY heat pipe.

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Roomba Vs Poop: Teaching Robots To Detect Pet Mess

August 24, 2016 by Adam Fabio 119 Comments

Imagine this: you come home after a day at work. As you open the door, your nose is the first alert that something is very, very wrong. Instead of the usual house smell, your nose is assaulted with the distinctive aroma that means your dog had an accident. The smell is stronger though — as if Fido brought over a few friends and they all had a party. Flipping the lights on, the true horror is revealed to you. This was a team effort, but only one dog was involved.

At some point after the dog’s deed, Roomba, your robot vacuum, took off on its scheduled daily run around the house. The plucky little robot performed its assigned duties until it found the mess. The cleaning robot then became an agent of destruction, smearing a foul smelling mess throughout the space it was assigned to clean. Technology sometimes has unintended consequences. This time, your technology has turned against you.

This scene isn’t a work of fiction. For a select few families, it has become an all too odoriferous reality just begging for a clever fix.

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