Japanese PossessedHand uses Arduino to move your fingers

Researchers at Tokyo University in cooperation with Sony have developed the prototype for a device capable of moving the fingers via electro-muscular control. Known as the PossessedHand, the device uses an Arduino to control 28 wrist-attached electrode pads which painlessly stimulate hand muscles to accomplish regular movements. This initiative holds potential not just for musical instruction, but also in the bio-medical field to assist stroke patients and others with neuromuscular impairment.

Via PopSci.

Hacking the PIC 18F1320

Andrew “Bunnie” Huang is well known for his Xbox hacks. He wanted to try out some reversing techniques on programmed PIC 18F1320 chips he acquired in order to read the secured FLASH memory.

After having the PICs commercially decapped, he analyzed the silicon under an electron microscope revealing the location of security bits relative to the FLASH memory he sought to read. In this tutorial he reveals the further tedious steps he took to complete hacking the PIC 18F1320 to read the memory data.

Via J. Peterson in comments.

ATmega168A pulse width modulation (PWM)

ProtoStack shows how to dim a LED using pulse width modulation and an ATmega168A:

Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. When you reduce current through an LED there are unintended consequences like color shifts and dropouts. A better way is to use Pulse Width Modulation (PWM).

With PWM the LED is turned on and off many times per second. By adjusting the percentage of on time vs off time, the brightness of the LED can be controlled. The diagram below shows 4 PWM wave forms with varying duty cycles. The 90% duty cycle example would produce the greatest brightness whilst the 10% duty cycle will produce the least. The selected period should be sufficiently short so that a flicker isn’t noticeable.

Thanks Daniel! Via the contact form.

Server status: Off the cloud

A few weeks ago we had some erratic down time, followed by a migration to a dedicated server. Things are looking great now. Pingdom says our average response time has gone from 1500ms to 430ms.

A ton of traffic from a single IP address first knocked us offline during the morning, US time. Our ISP blocked it for us, but the next day the blog was offline again. At first our ISP thought it was an attack on the blog admin page, but later suggested a bad plugin.

We now suspect it was an influx of traffic from a link in the Instructables newsletter, probably in conjunction with a poorly working WordPress plugin. It was impossible to troubleshoot the problem on the live site because there’s so little debug data available. We did the proper thing and threw more hardware at the problem.

It would be great to take the Adafruit route and get a fully managed server. ServInt’s cheapest full server is $200 a month, that’s a little out of our range. A quality shared host could handle 90% of our needs, but there’s no good debug data and they tend to catch fire during a high-traffic slashdotting.  A Virtual Private Server works great for a lot of people, but we’re even more nervous about a shared host plus a virtualization layer. We originally moved to Laughing Squid’s Rackspace cloud sublet so the site could magically expand to more servers as needed, but the cloud turned out to be a shared hosting ghetto too.

Begrudgingly, we chose a dedicated self-managed server with Hetzner. Even though it’s cheaper than the cloud, it was the option of last resort. Server setup and management detracts from hardware fun. We’re on our own for all future problems, but we have access to all the debug info. For our current size and budget, this was the best option.  We setup the dedicated box with a ton of help from Arhi, and we retained a system admin to secure it and maintain it long-term.

Our new home is an Athlon X2 5600 with 4GB RAM and 400GB mirrored RAID array. Debian Linux is running a standard Apache/MySQL/PHP server. Automated off-site backups run every 24 hours.

Cloud Flare caches websites at datacenters all over the world, they’re handling more than half our traffic now. Pages load faster from a server close to you than if everyone tries to grab them from our box in Germany.

See the site changelog for a complete list of updates from the past two years.

Thanks to Laughing Squid for being a great host, providing great support, and helping us move. Thanks to Arhi for his  extensive server configuration help. Thanks to everyone for enduring the transition.

Thermal Tweeter facts and figures FAQ @dangerousproto

A lot of questions are coming through the Thermal Tweeter. Here’s some answers:

  • How many rolls? About 1/day on Thursday, Friday, Saturday. 2.5 on Sunday, and it ran out twice for a few hours. Also, about 2/day of this variety.
  • The printer uses thermal paper in rolls. It doesn’t use ink.
  • Rolls were 5 for a buck, cheaper in bulk. We have to stock up today.
  • The paper has red stripes for a few meters from the end.
  • Average delay from tweet to viewing it print is around 30 seconds.  The printer checks for new @mentions every 30 seconds. There’s about 15 seconds of USTREAM delay too.
  • Only standard ASCII characters will print. Unicode is filtered out by the web platform when it processes the tweets. The printer does support a few extended characters, but not unicode. There’s no direct translation from unicode numbers to the extended characters supported by the printer, it would be a real pain to deal with that.
  • The printer knows when the paper is gone and stops printing.
  • All the tweets are in a pile on the floor, we’ll give some away at end
  • Almost 4 days of non-stop USTREAM using Adobe Flash Media Live app and a Firewire DV camera. As long as we keep the preview window minimized it doesn’t crash…
  • We don’t mind if you want to use a lot of paper or tweet via script, it makes it more interesting for people watching the USTREAM.
  • It cost about $100. The printer was $50 at SparkFun. The Web Platform is $40 at Seeed Studio, but we built our own.

See the design overview, and read the first system update.

Free PCB Sunday: Pick your PCB

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.

This week we’re giving away two coupon codes for the fee PCB drawer. Pick your own PCB. Remember you get unlimited free PCBs now – finish one and we’ll send you another!

Don’t forget there’s free PCBs three times every week:

  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend

Get the CoolRunner-II development board for $15 and XC9572XL dev-board  for $15.
Continue reading “Free PCB Sunday: Pick your PCB”

JTAG debugging introduction and simulation

Henrik writes:  This seems like a clever open source project, you can order a free kit or build it yourself based on the FTDI chips. Free software to develop or educate yourself on jtag.

goJTAG is the first university-driven open-source project aiming at providing a full package for a JTAG newcomer including training materials, slides and exercises. The software includes a simulation component that fully illustrates the underlaying concept of JTAG/Boundary Scan. The user can directly step-wise control the test features of IEEE 1149.1 compliant devices and observe a system’s reaction in a real time in an on-screen simulation. Using a PicoTAP controller, all actions can be applied to a unit under test (UUT) it is connected to. Such a fine-grain illustration of JTAG test principles has not been possible until now.

Via the contact form.

Driving a pinball DMD with an Arduino

Pinball machines are experiencing a resurgence in popularity. Whether resurrecting a vintage machine or building your own, issues with control of a visual display can arise. One form of display used in some modern machines is the plasma dot matrix display (DMD).

Adam Preble presents this video and article on his experiences driving a DMD using Arduino. Essentially, the Arduino controls all data to the DMD via 6 1/0 lines. The display is powered by the pinball machines power source. Adam notes that the Arduino version he used (which he states was an Atmega128, though most likely an Atmega8 or 168 since it was an NG board) was just barely fast enough to do a reasonable job of keeping the picture bright enough and flicker-less. Nevertheless, this serves as an ambitious proof of concept.

Arduino sketch code is posted on Github.

Via Poor Man’s Pinball.

Free O’Reilly webcast: Open Android


O’Reilly is presenting a free webcast on Open Android: What it means to be open and why you would care, on Friday, July 8, 2011 at 10 AM PT. The presentation by Marko Gargenta will last approximately 60 minutes.

Open is another buzz word that means many things to many people. In Open Android talk, we’ll explore how Android is open and why that is important to you. We’ll also look at where Android came from and where it could be going with its open-ness.

Register here.

Motherboard’s sound builders

Kaley Bolt writes:

This particular installment of Sound Builders takes the Motherboard team to the “Anti-Theory Workshop” of Reed Ghazala, the father of circuit bending. It’s a nice timely tease for this year’s Bent and I think fans of Dangerous Prototypes would be really into it.

With Ghazala as our guide, we navigate the history of circuit-bending sound art from its accidental beginnings in his childhood bedroom to the discovery’s lasting impact on electronic music and art. Host Jordan Redaelli even has a shot on the tinkered toys, creating a duet with the legendary circuit tweaker that is unique to say the least.

Via the contact form.

This particular installment of Sound Builders takes the Motherboard team to the “Anti-Theory Workshop” of Reed Ghazala, the father of circuit bending. It’s a nice timely tease for this year’s Bent and I think fans of Dangerous Prototypes would be really into it. 

With Ghazala as our guide, we navigate the history of circuit-bending sound art from its accidental beginnings in his childhood bedroom to the discovery’s lasting impact on electronic music and art. Host Jordan Redaelli even has a shot on the tinkered toys, creating a duet with the legendary circuit tweaker that is unique to say the least.

3D printing with solar sintered sand

Markus Kayser has a very interesting project, called SolarSinter, where he is using the energy from the sun to fuse sand into glass.  This is very thought provoking as it utilizes two very ubiquitous things solar energy and sand.  While the printer does not has very high precision at the moment, it does appear to have potential for additional automation and refinement.

A very interesting thought would be using these on a planet, like Mars, to fabricate buildings from local materials and solar energy.  The biggest question would be if the sand on Mars would sinter.

Continue reading “3D printing with solar sintered sand”

PropForth IDE for the Parallax Propeller


PropForth is a fully interactive development environment which runs on the Parallax Propeller allowing you to program the chip interactively in Forth using a PC serial terminal program. Their latest code release is Version 4.5.

According to their project description:

Propforth 4.5 introduces standardized interfaces (cog, serial, ethernet, etc), SD support (thanks caskaz), completed EEPROM filesystem support, forth code scripting (files that are loaded and interpreted as scripts that do not need to affect the dictionary), and Spinneret webserver support. The Spinneret support includes telnet, http, NTP, and RTC.

Check out the PropForth project download page for code, demos and docs. Also see the FAQ page.

App note: Extending the input voltage of op-amps

An app note on extending the  input voltage range of standard op-amps:

Using its own output to bootstrap a low-dropout voltage regulator (MAX6771) with high input-voltage range (up to 76V), this circuit extends the input range of a CMOS op amp (MAX4162) while preserving its high input impedance and very low input bias current (< 1pA).

Thanks rsdio!

A simple part: Pinheader connectors

From the Dangerous Prototypes partlist: pinheader connectors.

  • 0.1″ (2.54mm) header is the standard width of bread boards
  • Straight and right angle versions

They are used on every project we’ve made so far. Their standard pitch spacing makes them easy to use with breadboards, jumpers, and wires with female connectors on them. We use them on programing, IO, external power supply. and test headers.

TI F28M35H multicore microcontroller

Texas Instruments has a new milticore microcontroller that’s overflowing with communication peripherals:

The Concerto family is a multi-core system-on-chip microcontroller with independent communication and real-time control subsystems. The F28M35x is the first series in the Concerto family.

The communications subsystem is based on the industry-standard 32-bit ARM Cortex-M3 CPU and features a wide variety of communication peripherals, including Ethernet 1588, USB OTG with PHY, CAN, UART, SSI, I2C, and an external interface.

The real-time control subsystem is based on TI’s industry-leading proprietary 32-bit C28x Floating-Point CPU and features the most flexible and high-precision control peripherals, including ePWMs with fault protection, and encoders and captures-all as implemented by TI’s C2000 Piccolo and Delfino families

Thanks McZ!

Free PCB coupon via Facebook comments

Every Friday we give away some extra PCBs via Facebook. The first few people who comment on this at Facebook get a free PCB. More PCBs via Twitter on Tuesday and the blog every Sunday.

This week we’re giving away two PCB codes. Pick your own PCB from the free PCB drawer.

Don’t forget there’s free PCBs three times a every week:

  • Free PCB Sunday. The classic. Every week, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend

You can get a Bus Blaster v2 for $34.95.

Continue reading “Free PCB coupon via Facebook comments”

Get ready to drive your robo car in Nevada!

As a result of recent legislation, Nevada has become the first US state to allow driverless, autonomous vehicles on public roadways. The Nevada legislature passed Assembly Bill 511 which allows the operation of “autonomous vehicles”, defined as:

a motor vehicle that uses artificial intelligence, sensors and global positioning system coordinates to drive itself without the active intervention of a human operator.

Sensors are further defined, without limitation, as cameras, radar and lasers.

Its now up to the Nevada DOT to draft regulations to implement this legislation in the form of a new driver’s license endorsement permitting the operation of autonomous vehicles, as well as setting forth minimum equipment and insurance regs needed for such a vehicle to qualify as street legal.

Via PCWorld.