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• SMART Status Data Interpretation - Disk Utility

  - by Mah

  Last week my external harddisk (Seagate Barracuda 1.5TB in a custom enclosure) showed signs of failure (Disk Utility SMART Pre-failure status - several bad sectors) and I decided to change it. I bought a new HDD (Seagate Barracuda 2TB) and connected it to my Ubuntu box with a SATA to USB cable that could not report SMART status. I copied all the contents of the old HDD to the new HDD (one partition with rsync, the other with parted cp) and then gently replaced the old HDD with the new one inside my aluminum enclosure. For obscure reasons after reconnecting the new HDD through the old enclosure, the Linux box could not detect my partitions. I recovered the partitions with testdisk and restarted the computer. After the restart I checked the SMART status of the new HDD an I get this: Read Error Rate --------------- Normalized 108 Worst 99 Threshold 6 Value 16737944 I got a high value on the Seek Error Rate as well. Wondering why this happens I copied 2 GB directory from one partition to the other and rechecked the SMART status (5 minutes later). This time I got the following: Read Error Rate --------------- Normalized 109 Worst 99 Threshold 6 Value 24792504 As you see there has been an increase in the error rate. I am unable to interpret these numbers. Is my new hard disk already dying? What are the acceptable values in these fields for Seagate hard disks? Then why the assessment is still good? While I could get temperature and airflow temperature data from my old HDD, I can not fetch them for the new one. I noticed that my old hdd had got really hot sometimes. Is it possible that the enclosure is killing the harddisks due to high temperature?... Thanks

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• Roll a DIY Camera Jib for $25

  - by Jason Fitzpatrick

  Video gear is expensive; save your pennies by building a DIY camera jib for smooth camera movement on a budget. Over at Oliva tech they explain just how few parts you need to build their DIY jib: The guys here at the studio mocked up a simple DIY jib that is not only ridiculously inexpensive to piece together, but also very straight forward. The point of this jib was to get a very wide range of motion from top to bottom with only a few feet of 0.75? square tube, 1? angled aluminum, 1/4? nuts and bolts, and nylon washers is all you’ll need to put the jib together. This light weight jib can be used on small portable tripods, but will require a fluid head for panning left and right. Hit up the link below for a detailed parts list and build guide. How to Make a DIY Camera Jib [via Make] How to Own Your Own Website (Even If You Can’t Build One) Pt 1 What’s the Difference Between Sleep and Hibernate in Windows? Screenshot Tour: XBMC 11 Eden Rocks Improved iOS Support, AirPlay, and Even a Custom XBMC OS

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• Donkey Kong Wall Shelves [DIY Project Inspiration]

  - by Asian Angel

  Are you looking for inspiration for a geeky DIY project to get into over the holiday weekend? Then take a look at this fantastic looking set of Donkey Kong wall shelves created by artist Igor Chak! From the website: So here is a Donkey Kong wall, strong, good looking but still has its character. The wall is made out of individual sections; each section is made out of durable but light carbon fiber, anodized aluminum pixels that are joined with strong stainless steel rods and toughened glass tops. The special mounts themselves are made out of steel and can support up to 60 lbs. Igor’s notes and additional images for the project can be found approximately half way down the webpage linked below. If Donkey Kong is not your favorite game, this could still inspire a shelving project focused on the one you like best! Donkey Kong Wall [via Neatorama] HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? Java is Insecure and Awful, It’s Time to Disable It, and Here’s How What Are the Windows A: and B: Drives Used For?

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• How do you determine whether a website is a scam [closed]

  - by Tom

  What's the best way to determine if a website is a scam. For example, at first sight (no pun intended) the following website seems to be legitimate. But the price of the product is suspiciously low (all the reviews point to an RRP of approximately £1000). http://www.maxiargos.com/index.php/asus-zenbook-ux31e-dh72-13-3-inch-thin-and-light-ultrabook-silver-aluminum.html Another indication is the lack of SSL for the checkout page, and lack of useful information in the WHOIS record. Registration Service Provided By: TMDHOSTING Contact: +1.8665325635 Domain Name: MAXIARGOS.COM Registrant: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Creation Date: 09-Nov-2011 Expiration Date: 09-Nov-2012 Domain servers in listed order: ns1.tmdhosting410.com ns2.tmdhosting410.com Administrative Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Technical Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Billing Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676

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• Rapid Prototyping for Embedded Systems

  - by dr_pepper

  For doing prototyping on small embedded projects that require physical motion, what hardware prototyping tools are available? For my projects, I tend to spend more time finding parts (i.e. wood, aluminum, etc.) and making the proper cuts, measurements, and connections than writing the software and configuring the electrical hardware. Are there any affordable products that will enable me to create physical hardware that is strong enough to support motion? If not, what techniques or tools are available to help develop the physical hardware more quickly? Currently, I typically build my projects from wood and plastic scraps that I have lying around. What types of materials enable you to prototype more quickly? CLARIFICATION: By motion, I mean something that has to bear stress like a robot arm powered by a servo motor and could handle moving or carrying 1-2 lbs.

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• AMD FX8350 CPU - CoolerMaster Silencio 650 Case - New Water Cooling System

  - by fat_mike

  Lately after a use of 6 months of my AMD FX8350 CPU I'm experiencing high temperatures and loud noise coming from the CPU fan(I set that in order to keep it cooler). I decided to replace the stock fan with a water cooling system in order to keep my CPU quite and cool and add one or two more case fans too. Here is my case's airflow diagram: http://www.coolermaster.com/microsite/silencio_650/Airflow.html My configuration now is: 2x120mm intake front(stock with case) 1x120mm exhaust rear(stock with case) 1 CPU stock I'm planning to buy Corsair Hydro Series H100i(www.corsair.com/en-us/hydro-series-h100i-extreme-performance-liquid-cpu-cooler) and place the radiator in the front of my case(intake) and add an 120mm bottom intake and/or an 140mm top exhaust fan. My CPU lies near the top of the MO. Is it a good practice to have a water-cooling system that takes air in? As you can see here the front of the case is made of aluminum. Can the fresh air go in? Does it even fit? If not, is it wiser to get Corsair Hydro Series H80i (www.corsair.com/en-us/hydro-series-h80i-high-performance-liquid-cpu-cooler) and place the radiator on top of my case(exhaust) and keep the front 2x120mm stock and add one more as intake on bottom. If you have any other idea let me know. Thank you. EDIT: The CPU fan running ~3000rpm and temp is around 40~43C on idle and save energy. When temp is going over 55C when running multiple programs and servers on localhost(tomcat, wamp) rpm is around 5500 and loud! I'm running Win8.1 CPU not overclocked PS: Due to my reputation i couldn't post the links that was necessary. I will edit ASAP.

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• Ethernet/8P8C crimp contacts bent

  - by Fire Lancer

  (if anyone knows correct terminology please correct). Ive got a (fairly large) number of existing Ethernet cables that over the years many have got damaged connector clips, so got a crimp tool and some new connectors for them. However out of all 4 attempts I have tried, on crimping 2+ of the little copper contacts that bite into the wires have instead just bent to one side, and so gone between the gaps in in the crimp tool... Unless this really is me doing something wrong (what?) I am inclined to blame the hardware, but is this the crimper or the new connectors I got? I tried to take a picture, as you can just about see looking from the left 3rd, 6th, 7th and 8th pins didn't get pushed in, and so don't form a connector. Unfortunately my camera was barely able to focus on it and then this website converted it to a JPEG... Update: Connectors/Cable/Tools: The wires are stranded (looks about 6 and no evidence of being aluminum/not copper), and the pins(?) have 2 little flat spikes lengthways along the cables (I understand to dig into it, while solid core connectors would have like 2 plates designed to go around the core?). Crimper was http://www.amazon.co.uk/gp/product/B0013EXTKK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 (seemed to be highly rated, I already had tools for cutting/stripping). Update2: Picture of crimp "prongs" (?) Update3: Side picture of connector Update4: Comparison with old connector. The top (used) connector is one from a few years back (different tool and connectors), the thing that concerns me that it might not be the tool I need to replace is just how thin the pins are on the new one that maybe a tool could legitimately bend some into a gap rather than pushing them in fully? In fact I can move individual pins to the sides significantly with my fingernail, is that normal?

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• MacGyver Moments

  - by Geoff N. Hiten

  Denny Cherry tagged me to write about my best MacGyver Moment.  Usually I ignore blogosphere fluff and just use this space to write what I think is important.  However, #MVP10 just ended and I have a stronger sense of community.  Besides, where else would I mention my second best Macgyver moment was making a BIOS jumper out of a soda can.  Aluminum is conductive and I didn't have any real jumpers lying around. My best moment is probably my entire home computer network.  Every system but one is hand-built, usually cobbled together out of spare parts and 'adapted' from its original purpose. My Primary Domain Controller is a Dell 2300.   The Service Tag indicates it was shipped to the original owner in 1999.  Box has a PERC/1 RAID controller.  I acquired this from a previous employer for $50.  It runs Windows Server 2003 Enterprise Edition.  Does DNS, DHCP, and RADIUS services as a bonus.  RADIUS authentication is used for VPN and Wireless access.  It is nice to sign in once and be done with it. The Secondary Domain Controller is an old desktop.  Dual P-III 933 with some extra drives. My VPN box is a P-II 250 with 384MB of RAM and a 21 GB hard drive.  I did a P-to-V to my Hyper-V box a year or so ago and retired the hardware again.  Dynamic DNS lets me connect no matter how often Comcast shuffles my IP. The Hyper-V box is a desktop system with 8GB RAM and an AMD Athlon 5000+ processor.  Cost me less than $500 to put together nearly two years ago.  I reasoned that if Vista and Windows 2008 were the same code then Vista 64-bit certified meant the drivers for Vista would load into Windows 2008.  Turns out I was right. Later I added three 1TB drives but wasn't too happy with how that turned out.  I recovered two of the drives yesterday and am building an iSCSI storage unit. (Much thanks to Starwind.  Great product).  I am using an old AMD 1.1GhZ box with 1.5 GB RAM (cobbled together from three old PCs) as my storave server.  The Hyper-V box is slated for an OS rebuild to 2008 R2 once I get the storage system worked out.  maybe in a week or two. A couple of DLink Gigabit switches ties everything together. Add in the Vonage box, the three PCs, the Wireless-N Access Point, the two notebooks and the XBox and you have gone from MacGyver to darn near Rube Goldberg. The only thing I really spend money on is power supplies and fans.  I buy top-of-the-line for both. I even pull and crimp my own cables. Oh, and if my kids hose up a PC, I have all of their data on a server elsewhere.  Every PC and laptop is pretty much interchangable for email and basic workstation tasks.  That helps a lot too. Of course I will tag SQLVariant.

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• Upcoming Carbon Tax in South Africa

  - by Evelyn Neumayr

  By Elena Avesani, Principal Product Strategy Manager, Oracle In 2012, the South Africa National Treasury announced the plan to impose a carbon tax to cut carbon emissions that are blamed for climate change. South Africa is ranked among the top 20 countries measured by absolute carbon dioxide emissions, with emissions per capita in the region of 10 metric tons per annum and over 90% of South Africa's energy produced by burning fossil fuels. The top 40 largest companies in the country are responsible for 207 million tons of carbon dioxide, directly emitting 20 percent of South Africa’s carbon output. The legislation, originally scheduled to be implemented from January 2015 to 31 December 2019, is now delayed to January 2016. It will levy a carbon tax of R120 (US$11) per ton of CO2, rising then by 10 percent a year until 2020, while all sectors bar electricity will be able to claim additional relief of at least 10 percent. The South African treasury proposed a 60 percent tax-free threshold on emissions for all sectors, including electricity, petroleum, iron, steel and aluminum. Oracle Environmental Accounting and Reporting (EA&R) supports these needs and guarantees consistency across organizations in how data is collected, retained, controlled, consolidated and used in calculating and reporting emissions inventory. EA&R also enables companies to develop an enterprise-wide data view that includes all 5 of the key sustainability categories: carbon emissions, energy, water, materials and waste. Thanks to its native integration with Oracle E-Business Suite and JD Edwards EnterpriseOne ERP Financials and Inventory Systems and the capability of capturing environmental data across business silos, Oracle Environmental Accounting and Reporting is uniquely positioned to support a strategic approach to carbon management that drives business value. Sources: Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} African Utility Week BDlive Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• Windows 7 is shutting down unexpectedly, according to the logs.

  - by dlamblin

  Here's a message from my eventvwr EventLog (Windows Logs System): The previous system shutdown at 11:51:15 AM on ?7/?29/?2009 was unexpected. This is funny because I was wondering why the system shut down while I was playing Civilizations IV full screen. Now I know. It was unexpected. Has anyone encountered and resolved this? A little background: I am running Windows 7 RC inside VMWare Fusion 2 (just updated a few months back) on a MacBook (Bitterly not Pro) aluminum-body. Windows 7 occasionally will shut down. This isn't a quick turn-off, it's a shutdown where all the programs are exited, the system waits until they quit (and Civ4 doesn't prompt me to save), it even installed Windows Updates before restarting. And yes it is restarting right after the shutdown. Because I run a game in full screen mode I do not notice any dialog with a countdown timer or anything like that that might be a warning. As I have iStat on my dashboard widgets I can see about 8 temperature monitors. I have seen the CPU get up to 74C before, but during the shutdown, though it seemed hot to the touch (always is), it read 61C for the CPU, 60C for heatsink A, 50C for heatsink B and in the 30s-40s for the enclosure and harddrives. As I type this now, the temps are actually higher, so I don't think the temperature caused it. I have at least six such events dating first from 5/17 which was a week after installing Windows 7. I did find one information level warning from USER32 in the system log that says: The process C:\Windows\system32\svchost.exe (DLAMBLIN-WIN7) has initiated the restart of computer DLAMBLIN-WIN7 on behalf of user NT AUTHORITY\SYSTEM for the following reason: Operating System: Recovery (Planned) Reason Code: 0x80020002 Shutdown Type: restart Comment: And another 15 minutes before that from Windows Update: Restart Required: To complete the installation of the following updates, the computer will be restarted within 15 minutes: - Cumulative Security Update for Internet Explorer 8 for Windows 7 Release Candidate for x64-based Systems (KB972260) Which I think kind of explains it. Though I don't know why restarting after an update would create an error event of "shutdown was unexpected", isn't that pretty odd? Now, how do I set it to never restart after an update unless I click something. Application of solution: As fretje reminded me, there's a couple of configurable settings for this, in windows 7 they're much in the same place as in Windows 2000 SP3 and XP SP1. Running gpedit.msc pops up a window that looks like: Windows 7 has changed the order and added a couple of newer options I've italicized: Do not display 'Install Updates and Shut Down' in Shut Down Windows dialog box Do not adjust default option to 'Install Updates and Shut Down' in Shut Down Windows dialog box Enabling Windows Power Management to automatically wake up the system to install scheduled updates Configure Automatic Updates Specify intranet Microsoft update service location Automatic Updates detection frequency Allow non-administrators to receive update notifications Turn on Software Notifications Allow Automatic Updates immediate installation Turn on recommended updates via Automatic Updates No auto-restart with logged-on users for scheduled Automatic Updates Re-prompt for restart with scheduled installations. Delay Restart for scheduled installations Reschedule Automatic Updates schedule

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• OS X Snow Leopard 10.6 Refuses to Load Websites the first time intermittently

  - by Brandon

  Many times when I am browsing the web, Snow Leopard will sit and load a site for 20 seconds or more, until it times out and says it cannot be displayed. If I refresh, it loads RIGHT away, every time. The issue is intermittent but happens from once every couple of days to a few times a day. So the long and short of it is this: Aluminum MacBook (Non-Pro) 2.4GHz Core2Duo, 4GB DDR3 I am using 10.6.6 but I have had this issue since 10.6.0 It happens in Firefox, Chrome, and Safari I have flushed my DNS (using the command 'blablabla flush') I am using custom DNS servers which I hoped would fix it but it had no effect* I am running Apache currently but haven't been for most of the time I've reformatted multiple times, always experiencing the issue I am on Cox cable internet, with a Motorola Surfboard & a Belkin F6D4230-4 v1 (Pre?) N wireless router. I've put the router in G only & N only & G+N to no effect It seems to be domain dependant as I can sometimes load the Google cache right away, and sometimes other sites will load but Google will refuse My Powerbook G4 with Leopard, other Windows XP laptops, & my wired Win7 desktop do not suffer from the issue. *I recently started using these to escape the awful Cox redirect page on timeouts I'm almost positive the issue has happened on other networks but I can't recall a specific instance (I have a terrible memory). The problem is intermittent and fixable enough (I just have to wait until it times out and hit refresh one time) but incredibly annoying since I'm constantly reading documentation from a large variety of sites. EDIT: To clarify, this happens with ALL sites, not only specific sites. I haven't been able to detect any pattern to the failures, but one day Google.com will refuse to load while reddit.com will, and the next day vice versa. Keep in mind that waiting for a timeout and hitting refresh loads the page right away, every time. If I don't wait for the timeout, opening more links, hitting refresh, and clicking the link a billion times have no effect. It seems to be domain neutral, affecting sites seemingly at random. It doesn't seem to have anything to do with connection inactivity either, because I will be SSHed into different servers, uploading files, browsing, downloading, etc, and it will just quit loading Jquery.com (for example) until I sit and wait for a timeout. /EDIT This is my last resort. Please, someone, tell me what is happening. Thank you.

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• Why is my external USB hard drive sometimes completely inaccessible?

  - by Eliah Kagan

  I have an external USB hard drive, consisting of an 1 TB SATA drive in a Rosewill RX35-AT-SU SLV Aluminum 3.5" Silver USB 2.0 External Enclosure, plugged into my SONY VAIO VGN-NS310F laptop. It is plugged directly into the computer (not through a hub). The drive inside the enclosure is a 7200 rpm Western Digital, but I don't remember the exact model. I can remove the drive from the enclosure (again), if people think it's necessary to know that detail. The drive is formatted ext4. I mount it dynamically with udisks on my Lubuntu 11.10 system, usually automatically via PCManFM. (I have had Lubuntu 12.04 on this machine, and experienced all this same behavior with that too.) Every once in a while--once or twice a day--it becomes inaccessible, and difficult to unmount. Attempting to unmount it with sudo umount ... gives an error message saying the drive is in use and suggesting fuser and lsof to find out what is using it. Killing processes found to be using the drive with fuser and lsof is sometimes sufficient to let me unmount it, but usually isn't. Once the drive is unmounted or the machine is rebooted, the drive will not mount. Plugging in the drive and turning it on registers nothing on the computer. dmesg is unchanged. The drive's access light usually blinks vigorously, as though the drive is being accessed constantly. Then eventually, after I keep the drive off for a while (half an hour), I am able to mount it again. While the drive doesn't work on this machine for a while, it will work immediately on another machine running the same version of Ubuntu. Sometimes bringing it back over from the other machine seems to "fix" it. Sometimes it doesn't. The drive doesn't always stop being accessible while mounted, before becoming unmountable. Sometimes it works fine, I turn off the computer, I turn the computer back on, and I cannot mount the drive. Currently this is the only drive with which I have this problem, but I've had problems that I think are the same as this, with different drives, on different Ubuntu machines. This laptop has another external USB drive plugged into it regularly, which doesn't have this problem. Unplugging that drive before plugging in the "problem" drive doesn't fix the problem. I've opened the drive up and made sure the connections were tight in the past, and that didn't seem to help (any more than waiting the same amount of time that it took to open and close the drive, before attempting to remount it). Does anyone have any ideas about what could be causing this, what troubleshooting steps I should perform, and/or how I could fix this problem altogether? Update: I tried replacing the USB data cable (from the enclosure to the laptop), as Merlin suggested. I should've tried that long ago, since it fits the symptoms perfectly (the drive works on another machine, which would make sense because the cable would be bent at a different angle, possibly completing a circuit of frayed wires). Unfortunately, though, this did not help--I have the same problem with the new cable. I'll try to provide additional detailed information about the drive inside the enclosure, next time I'm able to get the drive working. (At the moment I don't have another machine available to attach it.) Major Update (28 June 2012) The drive seems to have deteriorated considerably. I think this is so, because I've attached it to another machine and gotten lots of errors about invalid characters, when copying files from it. I am less interested in recovering data from the drive than I am in figuring out what is wrong with it. I specifically want to figure out if the problem is the drive or the enclosure. Now, when I plug the drive into the original machine where I was having the problems, it still doesn't appear (including with sudo fdisk -l), but it is recognized by the kernel and messages are added to dmesg. Most of the message consist of errors like this, repeated many times: [ 7.707593] sd 5:0:0:0: [sdc] Unhandled sense code [ 7.707599] sd 5:0:0:0: [sdc] Result: hostbyte=invalid driverbyte=DRIVER_SENSE [ 7.707606] sd 5:0:0:0: [sdc] Sense Key : Medium Error [current] [ 7.707614] sd 5:0:0:0: [sdc] Add. Sense: Unrecovered read error [ 7.707621] sd 5:0:0:0: [sdc] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 [ 7.707636] end_request: critical target error, dev sdc, sector 0 [ 7.707641] Buffer I/O error on device sdc, logical block 0 Here are all the lines from dmesg starting with when the drive is recognized. Please note that: I'm back to running Lubuntu 12.04 on this machine (and perhaps that's a factor in better error messages). Now that the drive has been plugged into another machine and back into this one, and also now that this machine is back to running 12.04, the drive's access light doesn't blink as I had described. Looking at the drive, it would appear as though it is working normally, with low or no access. This behavior (the errors) occurs when rebooting the machine with the drive plugged in, and also when manually plugging in the drive. A few of the messages are about /dev/sdb. That drive is working fine. The bad drive is /dev/sdc. I just didn't want to edit anything out from the middle.

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• Robotic Arm &ndash; Hardware

  - by Szymon Kobalczyk

  This is first in series of articles about project I've been building  in my spare time since last Summer. Actually it all began when I was researching a topic of modeling human motion kinematics in order to create gesture recognition library for Kinect. This ties heavily into motion theory of robotic manipulators so I also glanced at some designs of robotic arms. Somehow I stumbled upon this cool looking open source robotic arm: It was featured on Thingiverse and published by user jjshortcut (Jan-Jaap). Since for some time I got hooked on toying with microcontrollers, robots and other electronics, I decided to give it a try and build it myself. In this post I will describe the hardware build of the arm and in later posts I will be writing about the software to control it. Another reason to build the arm myself was the cost factor. Even small commercial robotic arms are quite expensive – products from Lynxmotion and Dagu look great but both cost around USD $300 (actually there is one cheap arm available but it looks more like a toy to me). In comparison this design is quite cheap. It uses seven hobby grade servos and even the cheapest ones should work fine. The structure is build from a set of laser cut parts connected with few metal spacers (15mm and 47mm) and lots of M3 screws. Other than that you’d only need a microcontroller board to drive the servos. So in total it comes a lot cheaper to build it yourself than buy an of the shelf robotic arm. Oh, and if you don’t like this one there are few more robotic arm projects at Thingiverse (including one by oomlout). Laser cut parts Some time ago I’ve build another robot using laser cut parts so I knew the process already. You can grab the design files in both DXF and EPS format from Thingiverse, and there are also 3D models of each part in STL. Actually the design is split into a second project for the mini servo gripper (there is also a standard servo version available but it won’t fit this arm).  I wanted to make some small adjustments, layout, and add measurements to the parts before sending it for cutting. I’ve looked at some free 2D CAD programs, and finally did all this work using QCad 3 Beta with worked great for me (I also tried LibreCAD but it didn’t work that well). All parts are cut from 4 mm thick material. Because I was worried that acrylic is too fragile and might break, I also ordered another set cut from plywood. In the end I build it from plywood because it was easier to glue (I was told acrylic requires a special glue). Btw. I found a great laser cutter service in Kraków and highly recommend it (www.ebbox.com.pl). It cost me only USD $26 for both sets ($16 acrylic + $10 plywood). Metal parts I bought all the M3 screws and nuts at local hardware store. Make sure to look for nylon lock (nyloc) nuts for the gripper because otherwise it unscrews and comes apart quickly. I couldn’t find local store with metal spacers and had to order them online (you’d need 11 x 47mm and 3 x 15mm). I think I paid less than USD $10 for all metal parts. Servos This arm uses five standards size servos to drive the arm itself, and two micro servos are used on the gripper. Author of the project used Modelcraft RS-2 Servo and Modelcraft ES-05 HT Servo. I had two Futaba S3001 servos laying around, and ordered additional TowerPro SG-5010 standard size servos and TowerPro SG90 micro servos. However it turned out that the SG90 won’t fit in the gripper so I had to replace it with a slightly smaller E-Sky EK2-0508 micro servo. Later it also turned out that Futaba servos make some strange noise while working so I swapped one with TowerPro SG-5010 which has higher torque (8kg / cm). I’ve also bought three servo extension cables. All servos cost me USD $45. Assembly The build process is not difficult but you need to think carefully about order of assembling it. You can do the base and upper arm first. Because two servos in the base are close together you need to put first with one piece of lower arm already connected before you put the second servo. Then you connect the upper arm and finally put the second piece of lower arm to hold it together. Gripper and base require some gluing so think it through too. Make sure to look closely at all the photos on Thingiverse (also other people copies) and read additional posts on jjshortcust’s blog: My mini servo grippers and completed robotic arm  Multiply the robotic arm and electronics Here is also Rob’s copy cut from aluminum My assembled arm looks like this – I think it turned out really nice: Servo controller board The last piece of hardware I needed was an electronic board that would take command from PC and drive all seven servos. I could probably use Arduino for this task, and in fact there are several Arduino servo shields available (for example from Adafruit or Renbotics).  However one problem is that most support only up to six servos, and second that their accuracy is limited by Arduino’s timer frequency. So instead I looked for dedicated servo controller and found a series of Maestro boards from Pololu. I picked the Pololu Mini Maestro 12-Channel USB Servo Controller. It has many nice features including native USB connection, high resolution pulses (0.25µs) with no jitter, built-in speed and acceleration control, and even scripting capability. Another cool feature is that besides servo control, each channel can be configured as either general input or output. So far I’m using seven channels so I still have five available to connect some sensors (for example distance sensor mounted on gripper might be useful). And last but important factor was that they have SDK in .NET – what more I could wish for! The board itself is very small – half of the size of Tic-Tac box. I picked one for about USD $35 in this store. Perhaps another good alternative would be the Phidgets Advanced Servo 8-Motor – but it is significantly more expensive at USD $87.30. The Maestro Controller Driver and Software package includes Maestro Control Center program with lets you immediately configure the board. For each servo I first figured out their move range and set the min/max limits. I played with setting the speed an acceleration values as well. Big issue for me was that there are two servos that control position of lower arm (shoulder joint), and both have to be moved at the same time. This is where the scripting feature of Pololu board turned out very helpful. I wrote a script that synchronizes position of second servo with first one – so now I only need to move one servo and other will follow automatically. This turned out tricky because I couldn’t find simple offset mapping of the move range for each servo – I had to divide it into several sub-ranges and map each individually. The scripting language is bit assembler-like but gets the job done. And there is even a runtime debugging and stack view available. Altogether I’m very happy with the Pololu Mini Maestro Servo Controller, and with this final piece I completed the build and was able to move my arm from the Meastro Control program.   The total cost of my robotic arm was: $10 laser cut parts $10 metal parts $45 servos $35 servo controller ----------------------- $100 total So here you have all the information about the hardware. In next post I’ll start talking about the software that I wrote in Microsoft Robotics Developer Studio 4. Stay tuned!

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