Build Your Own Sensor Skin

February 29, 2016 by 25 Comments

Scientific research, especially in the area of robotics, often leverages cutting-edge technology. Labs filled with the latest measurement and fabrication gear are unleashed on the really tough problems, like how to simulate the exquisite sensing abilities of human skin. One lab doing work in this area has taken a different approach, though, by building multi-functional sensors arrays from paper.

A group from the King Abdullah University of Science and Technology in Saudi Arabia, led by [Muhammad M. Hussain], has published a fascinating paper that’s a tour de force of getting a lot done with nothing. Common household items, like Post-It notes, kitchen sponges, tissue paper, and tin foil, are used to form the basis of what they call “paper skin”. Fabrication techniques – scissors and tape – are ridiculously simple and accessible to anyone who made it through kindergarten.

They do turn to a Circuit Scribe pen for some of their sensors, but even this nod to high technology is well within their stated goal of making it possible for anyone to fabricate sensors at home. The paper goes into great detail about how the sensors are made, how they interact, and how they are interfaced. It’s worth a read to see what you can accomplish with scraps.

For another low-tech paper-based sensor, check out this capacitive touch sensor keyboard.

Thanks for the tip, [Mattias]

Spice Power

February 29, 2016 by 8 Comments

Spice is a circuit simulator that you should have in your toolbox. While a simulator can’t tell you everything, it will often give you valuable insight into the way your circuit behaves, before you’ve even built it. In the first installment of this three-part series, I looked at LTSpice and did a quick video walkthrough of a DC circuit. This time, I want to examine two other parts of Spice: parameter sweeps and AC circuits. So let’s get to it.

schem2In the first installment, I left you with a cliffhanger. Namely the question of maximum power transfer using this simple circuit. If you run the .op simulation you’ll get this result:

--- Operating Point ---
V(n001): 5 voltage
I(R1): 0.1 device_current
I(V1): -0.1 device_current

The power in R1 (voltage times current) is .5 W or 500 mW if you prefer. You probably know that the maximum power in a load occurs when the load resistor is the same as the source resistance. The Rser parameter sets the voltage source’s internal resistance. You could also have created a new resistor in series with V1 and set it explicitly.

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2,100 Mechanical Mechanisms

February 29, 2016 by 29 Comments

[Nguyen Duc Thang]’s epic 2100 Animated Mechanical Mechanisms is one of the best YouTube channels we’ve ever seen. A retired mechanical engineer, [Nguyen Duc Thang] has taken on an immense challenge: building up 3D models of nearly every imaginable mechanism in Autodesk Inventor, and animating them for your amusement and enlightenment. And, no, we haven’t watched them all for you, but we’re confident that you’ll be able to waste at least a couple of hours without our help.

If you’re actually looking for something specific, with this many mechanisms demonstrated, YouTube is not the perfect lookup table. Thankfully, [Nguyen Duc Thang] has also produced a few hundred pages of documentation (PDFs, zipped) to go along with the series, with each mechanism classified, described, and linked to the video.

This is an amazing resource as it stands, and it’s probably a good thing that we don’t have access to the 3D files; between the filament cost and the time spent shepherding our 3D printer through 2,100 mechanisms, we’d be ruined. Good thing we don’t know about the Digital Mechanism and Gear Library or KMODDL.

Thanks [alnwlsn] for the tip!
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PCB Laminator Is Its Own Project

February 29, 2016 by 21 Comments

One of the easiest ways to make PC boards at home is to use the toner transfer method. The idea is simple: print the artwork using a laser printer and then use a clothes iron to transfer the toner from the paper to a clean copper clad board. The toner is essentially plastic, so it will melt and stick to the board, and it will also resist etchant.

There are several things you can do to make things easier. The first is the choice of paper. However, the other highly variable part of the process is the clothes iron. You have to arrange for the right amount of heat and pressure. If you don’t do a lot of boards, you’ll probably have to make several passes at getting this right, scrubbing the reject boards with acetone and scouring pads to clean them again.

[Igor] had enough of the clothes iron and knew that other people have used lamination machines to get the toner off the paper and on the blank board. He started with a commercial laminator but hacked it for PID control of the temperature and made other improvements.

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SensorTape Unrolls New Sensor Deployment Possibilities

February 29, 2016 by 20 Comments

An embedded MEMS sensor might be lots of fun to play with on your first foray into the embedded world–why not deploy a whole network of them? Alas, the problem with communicating with a series of identical sensors becomes increasingly complicated as we start needing to handle the details of signal integrity and the communication protocols to handle all that data. Fortunately, [Artem], [Hsin-Liu], and [Joseph] at MIT Media Labs have made sensor deployment as easy as unraveling a strip of tape from your toolkit. They’ve developed SensorTape, an unrollable, deployable network of interconnected IMU and proximity sensors packaged in a familiar form factor of a roll of masking tape.

Possibly the most interesting technical challenge in a string of connected sensor nodes is picking a protocol that will deliver appreciable data rates with low latency. For that task the folks at MIT Media labs picked a combination of I²C and peer-to-peer serial. I²C accomodates the majority of transmissions from master to tape-node slave, but addresses are assigned dynamically over serial via inter-microcontroller communication. The net effect is a fast transfer rate of 100 KHz via I²C with a protocol initialization sequence that accommodates chains of various lengths–up to 128 units long! The full details behind the protocol are in their paper [PDF].

With a system as reconfigurable as SensorTape, new possibilities unfold with a solid framework for deploying sensors and aggregating the data. Have a look at their video after the break to get a sense of some of the use-cases that they’ve uncovered. Beyond their discoveries, there are certainly plenty others. What happens when we spin them up in the dryer, lay them under our car or on the ceiling? These were questions we may never have dreamed up because the tools just didn’t exist! Our props are out to SensorTape for giving us a tool to explore a world of sensor arrays without having to trip over ourselves in the implementation details.

via [CreativeApplications]

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Announcing Hackaday Belgrade’s Talks And Speakers

February 29, 2016 by 2 Comments

Hackaday is hosting a hardware conference in Belgrade on April 9th. This is arguably our first-ever European conference, and for the last few months we’ve been putting together a hackable conference badge, a list of speakers, and a set of hands-on workshops. Now, we’re finally ready to announce the workshops and talks for Hackaday | Belgrade. You can check out the scheduled talks and workshops below.

Tickets for Hackaday | Belgrade are still available, and tickets for the workshops will open up today. Tickets are also cheap – $35 for a regular ticket, and about $10 and $30 for the robot and DIY musical toy workshops, respectively. The workshop tickets are only to cover material cost, and you’ll get to take your project home with you.

The conference will be a blast. There will be bands and DJs, badge hacking competitions, and ten hours of talks and workshops. If you’re going, or are still on the fence, hang out on the event page to get the inside info on a few Hackaday events that will happen the night before and the day after.

The Workshops

Radomir Dopieralski – Tote, A Walking Quadruped Robot. Build your own spider-like robot and make it walk.

Anastasios Stamou – Hardware Hacking Musical Toys & DIY Electronic Musical Interfaces. Introductory circuit bending workshop teaching all the necessary techniques for designing and making experimental electronic musical interfaces out of recycled material.

The Talks

Voja Antonic – Hacking the Hackaday Belgrade Badge. The Belgrade conference features its own badge designed by Voja Antonic. Voja will introduce the Belgrade badge and the theory of operation behind the LED matrix, keyboard, power management, infrared transceiver, and accelerometer.

Navid Gornall – How To Eat Your Own Face. The story of hacking a 3D printer to print burger selfies with mayo. Printing with a non-Newtonian condiment presents a unique set of challenges which will be explored in this presentation.

Tsvetan Usunov – Hacker Friendly OSHW DIY Modular Laptop. Tsvetan is the mind behind Olimex, manufacturer of various embedded development platforms and tools. He will talk about the creation of a modular, hacker friendly laptop based on a 64-bit ARM processor.

Chris Gammell – Top Down Electronics

Dejan Ristanovic – Serbia: Long Road To The Internet. During the 1980s and 1990s, we had to hack the system in many ways just to stay connected, and to reinvent the wheel three times before breakfast. We also had some results, including Sezam, the biggest BBS in this part of Europe

Kristina Kapanova – Designing A High Performance Parallel Personal Cluster. This talk introduces an open source, homebrew mini cluster consisting of a Radxa Pro single board computer based on the quad-core ARM Cortex-A9 CPU. In particular, this talk demonstrates it is possible to achieve very advanced simulations in the field of quantum computing.

Sophi Kravitz – Creation, fabrication, and application by experimentation of the synchronization of a grid configuration of a light radiation orientation polarization illumination.

Seb Lee-Delisle – Making The Laser Light Synths. The Laser Light Synths are LED emblazoned musical instruments that anyone can play. Along with high power lasers, they form part of a large outdoor installation that switch the traditional roles of audience and performer.

Mike Harrison – Retrotechular : 1950s Video Projection Technology. A talk on the history and technology of the Eidophor, a little known, absurdly complicated, and very expensive product that dominated the large-screen projection market from the 1950s to the 1990s.

Peter Isza – Open Source Clinical Grade Electrocardiography. This talk covers the development of a true clinical grade, open source Holter ECG which will be sold for close to its manufacturing cost.

Paulina Stefanovic – Interactive Digital Storytelling Systems: Generative Interfaces, Authors and the Role of the Audience. This talk will cover the development and design of interactive content and interactive performance that shifts the focus from the creator of the system to the creative involvement of the audience.

BelgradeSpeakers-02-01

Introducing The Raspberry Pi 3

February 28, 2016 by 250 Comments

TL;DR: The Raspberry Pi 3 Model B is out now. This latest model includes 802.11n WiFi, Bluetooth 4.0, and a quad-core 64-bit ARM Cortex A53 running at 1.2 GHz. It’s a usable desktop computer. Available now at the usual Pi retailers for $35.

News of the latest Raspberry Pi swept around the Internet like wildfire this last weekend, thanks to a published FCC docs showing a Pi with on-board WiFi and Bluetooth. While we thank the dozens of Hackaday readers that wrote in to tell us about the leaked FCC documents, our lips have been sealed until now. We’ve been doing a few hands-on tests with the Pi 3 for about two weeks now, and the reality of the Pi 3 is much cooler than a few leaked FCC docs will tell you.

The Raspberry Pi 3 Model B features a quad-core 64-bit ARM Cortex A53 clocked at 1.2 GHz. This puts the Pi 3 roughly 50% faster than the Pi 2. Compared to the Pi 2, the RAM remains the same – 1GB of LPDDR2-900 SDRAM, and the graphics capabilities, provided by the VideoCore IV GPU, are the same as they ever were. As the leaked FCC docs will tell you, the Pi 3 now includes on-board 802.11n WiFi and Bluetooth 4.0. WiFi, wireless keyboards, and wireless mice now work out of the box.

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