First off, I haven’t been blogging for a long time. I am so busy at SATV that I haven’t even had time to play computer games. I got to finish a small project this month; it is rare for me to finish nearly anything, so I’m very happy.
This is an SNTP display clock. For years I have wanted a clock display for SATV. You’ve probably seen the big clocks, analog and digital, in many broadcast facilities. All of these clocks are kept in sync with a common timekeeping server. At WHDH-TV some years ago, I saw these throughout all the corridors of the station.
Nowadays, NTP is widely deployed and would be the perfect solution. Except for one thing: The displays have been very expensive; I got a quote from one vendor of NTP displays of $1,000 per each display. That wasn’t going to happen.
It is galling, especially when GPS-based NTP servers are readily available and very inexpensive; I set up SATV with an NTP server that I plan to write about. The cost was less than $200 for the GPS and the assorted interconnecting hardware!
But we still don’t have a display.
I’d been exploring various microcontroller dev boards for years when a friend came across the #Twatch:
#Twatch, Courtesy of Dangerous Prototypes.
The #Twatch is a common LCD display that connects via Ethernet to Twitter and retrieves the 10 most popular hashtags trending at any given moment. While I’m on Twitter myself, I couldn’t see myself using it; my friend got an extra unit and suggested, strongly, that I might want it. I had an idea.
I reprogrammed my #Twatch to be a very basic SNTP display. The Microchip controller on the board has very limited configuration memory and the lifespan of the program memory is limited to 100 flashes or so. The most basic display I could get without configuration would be one that would display UTC—no time zones could be configured—and that would also use the default worldwide NTP server pool at pool.ntp.org.
(I could not use my own NTP server that I set up a year ago for just this kind of project, but this would still be very acceptable for a human-readable display; my Nook Tablet does the same thing.)
You can see the result at the top of this post.
I also had more work to do. The original #Twatch also had an emulation mode for the popular Matrix Orbital LCD displays that overclockers and hackers often use with their PC’s. I had to preserve that, and also make it easy for my SBS machine to send alerts to the display.
I wrote a PowerShell module to interface to the display. That task was surprisingly involved. I had to re-learn PowerShell modules, learn C (which I had never used before—my experience went from Basic, Fortran and Pascal and skipped over C to Java and C#), learn about a microcontroller I may or may not use again, and write a PDF manual!
Here’s a video:
The #Twatch is out of production, unfortunately, but I still learned much from the project. This is the first embedded microcontroller project I have ever finished after years of collecting dev boards—but this won’t be my last! I expect to make more SNTP clocks.
I posted a more detailed explanation of my code on the Dangerous Prototypes #Twatch forum.
Ian gave me a nice hat tip! Thanks!
Since the #Twatch is out of production, I have been looking at alternatives to recommend. Guido Socher built an NTP clock from a AVR webserver board that’s very similar, except his is configurable. He’s selling a kit as well.
Perhaps now I can get back to writing about SBS. Or games.
A regular ritual of mine around this time of year is Embedded Systems Conference. This conference and trade show is held every fall in Boston. I’ve been going for years, including last year, and the year before that. I love going. I’ve always had a side interest in electronics and I’m a ham radio operator (N1KGH), and I seldom get many chances to see and work with electronics on a regular basis.
This year, scopes were everywhere! I attended Rohde & Schwarz’s lab, and got to use the scope you see in the (too blurry!) photo above. I didn’t get to spend a lot of time on it, but I did get to try the lab myself after my fellow attendees finished their session on the machine.
The lab involved inspecting a digital waveform with some deliberate glitches put in it by the demo board on the table. (All the test & measurement vendors have boards like these.) I had to define a mask on the screen, sort of a box, that would make the scope trigger if a “bad” waveform is detected. I got through that OK after briefly chatting with the lab instructor. The scope you see here has a touchscreen and it runs Windows 7 Embedded (no joke! I watched someone open up Windows dialogs and menus on the thing as if it were their laptop.)
At about $17,000, I won’t be having one any time soon, but I had no trouble using it considering I’d had only a few minutes to learn it.
I didn’t want to be in a dark room all day so I went to the show floor and tried out another scope lab, this one by Tektronix:
(My Kodak Zi8 really isn’t that great at run-and-gun shooting. Sorry.)
This lab was similar to the Rohde & Schwarz lab except there was a good-sized line to be seated. The Tek instructor had me do a different exercise: Their scope was connected to a board with a microcontroller and a 2.4 GHz WiFi module and I had to use the scope to answer questions like, what is the exact frequency of the LO in the module, how long does it take to receive a command, start transmitting and settle down, and so forth.
Their scope, like many digital scopes, is “mixed signal”, and has not only the traditional scope probes (4 channels) but also a digital interface, a bunch of clips connected to a ribbon cable like in a logic analyzer. The scope I used had a serial interface trigger (to connect to SPI or I2C, two very-common serial standards you probably never heard of) and an FFT module to measure frequency. It being a digital scope, it had cursors you could place on the start and end of waveforms and measure time. Like most demos, the exercises are always a little contrived and nudged to show the specific advantages of the product, but I still appreciated turning the knobs.
Tek was handing out a beautiful retro T-shirt:
That is Tektronix’s original logo. I would be lying if I said that I never used or owned a scope with that logo. (I once owned three tube-powered Tek scopes.)
Elsewhere on the show floor, I took advantage of an offer Texas Instruments was promoting: If you turned in a competitor’s development board, you could get one of TI’s dev boards in return. I turned in an old Zilog Z8 Encore board that I had bought at a past show in 2001, but never really used. (Most of my dev hardware is TI nowadays, plus a Netduino that I will write about if I ever make the time to play with it.)
I got a watch in return:
The eZ430-Chronos is a highly integrated, wearable wireless development system that comes in a sports watch. It may be used as a reference platform for watch systems, a personal display for personal area networks, as a wireless sensor node for remote data collection, or simply as a watch.
It’s quite a device. It has a wireless interface to send data back and forth; the intended application is a sports watch; it has an accelerometer and an interface to an optional heart-rate monitor, and a USB wireless dongle to send workout data to a PC to be compiled.
I probably won’t use it for exercise but the wireless feature would be great for automatic time synchronization with the NTP server I run at home. Also, it’s the biggest watch display for its size that I’ve ever used. It will be a very functional watch, at least when I’m not reprogramming it.
Oh, the XJTAG booth babes were here, again:
And someone called Smart Bear:
That’s it for 2011. Perhaps next year I’ll remember to look at the complimentary coupons in the bag they give to every attendee. There was an offer for yet another dev board and I missed it! (And I can’t even remember the vendor.)
An old joke in the computer and electronics technical communities is the idea of “magic smoke”. The joke is, electronic components have magic smoke in them. Overheat and let out the smoke and the component (and usually the device!) doesn’t work anymore.
I was working on a friend’s computer. My diagnosis on his only two-year-old HP system was that the motherboard and power supply was defective; I was certain the motherboard was bad, and could not rule out the PS, so I made arrangements to get new parts.
Motherboard for his gently-used computer: $350. So much for that. We (his sister and I) arranged to get a new machine from Staples and I would migrate the data from his old hard drive.
Until that moment, I had been running his old hard drive on my laptop using a USB to SATA adapter that is often used by hardware techs and there was no hint whatsoever of any problems. I had no reason to think the HD was defective—I could bring it up and read his files whenever I felt like it.
That changed when I provisioned his new machine, put everything the way he expected it, put his copy of Norton 360 on it, and so forth. Hindsight says I should have copied his files while the HD was on my laptop but I was thinking “look but not touch!” I just wanted to ascertain that the HD hardware was good, and the SMART data was fine (it was)—I wasn’t going to tinker with his disk if I didn’t have to.
I spun up the drive with my adaptor and plugged it into his machine. OK, I smell something hot—the drive is in the palm of my hand because of how my SATA adapter works. It’s not spinning—another reason I like to (carefully!) have my hand on an HD is because I can feel it spin up, or fail to spin up, or grind the heads.
No activity. It’s still hot.
My friend and I both notice the smoke. (“Whoa, Dave, what’s that!”)
I unplugged the disk and put everything away.
This is what it looked like on my workbench:
In the opening image to this post, you’ll notice two surface-mount zener diodes on a working Samsung hard drive. These are widely used in computer power supplies and major components such as motherboards. They are the basis for voltage regulation upon which we all depend on in nearly every electronic gadget.
This hard drive was also a Samsung, which made it easy to compare this drive to one of my good ones.
What happened to the diode in the 2nd picture??
There is solder on the pads where the diode would normally go, so the component was definitely intended to be there. It was there.
I’ve smoked various broken devices and homemade projects on my workbench at home. Way back in the days when people first made their own computers in the ‘70s, a popular way to learn how ROMs (Read Only Memories) worked was build your own out of these little glass 1N4148 diodes. The diodes, when connected, were all “1’s”. You got “0’s” in your ROM by putting a heavy-duty power supply across the diode in reverse, which would kill it. You’d see a nice flash of light. People still call it “blowing ROM’s”.
I’ve never seen components just disappear in a puff of smoke!
But my friend and I just did.
Eventually, my friend got his data from an online backup he paid for when he got the Norton product. Samsung’s disk business has been bought by Seagate so I may not see another dead drive from them again.
I’ve tried getting an RMA for this drive but Samsung insists it was bought out of market, likely to discourage gray market use. And discourage me from buying HP, permanently, but that’s another post. I usually offer the platters from any HD that is out of warranty or cannot be returned to SATV staffers and other people I work for.
My friend will get some platters to use as paperweights or coasters.
I’ve had to put aside my home electronics activities for a long time due to nearly losing my eyesight several years ago. While things are better for me now, it’s high time I took advantage of my long-time love of electronics and technology. This is my workbench. It’s cluttered but before I cleaned it for a house inspection, it was much worse.
Tools. The small box at the lower left had the cabling tools I used at SATV.
Some of my test equipment. You may have seen the small Triplett DMM on my workbench. Here is a decibel meter, a Kill-A-Watt, and in the reused Norelco pouch, a Bus Pirate (a very useful tool for connecting to serial buses.)
And I have a scope cart.
The scope and frequency counter work—the scope is a HP 1722 with good 275 MHz bandwidth. The counter only does 60 MHz so I’ll need a new one for my ham radio work. (Someday) The DMM at the bottom is a sick HP 3440—it has a broken switch in the signal path, but I do expect it to be fixable.
A collection of microcontroller development kits. One Z8 Encore I played with and bought at ESC some years ago, and three MSP 430’s, one of which is a wireless module.
I never had time to really use them. I really got into the Z8, but when I looked into getting a network stack for it I had sticker shock. I could really use a Ethernet module such as the Spinneret Web Server coupled with an cheap GPS module. SATV has wanted a GPS NTP source for a very long time. I’d like to be able to get the Ethernet and controller for less than $50 with a network stack and a toolchain (compiler/linker/debugger) that goes well with my Windows background.
I even have a “new” 12V worklight, of sorts:
It’s the lamp from one of my old broken scanners. It works. The hardest part will be building an enclosure. I never have enough lights.
I’m just glad to be tinkering again.
In addition to the Seagate I took apart, I had two Western Digital 200G drives that I was using in my HighPoint RAID controller. They’d been in service for over five years and were working the day I removed them for 1T drives. It was later a frustrating moment when I wanted to use the drives in enclosures for scratch purposes—neither drive would spin up! I’ve usually been able to repurpose old internal drives for external enclosures but not these. I still have fewer enclosures than I need (and a brand new Samsung drive with no place to go for the moment.) Above, you’re looking at the main mounting plate of the drive. You can see the head arm, and its reflection on the drive platter, through an access hole that is normally covered by a sticker (“removal of stickers voids warranty”, goes the label on many drives.)
Here’s Western Digital’s controller board. With the ubiquitous Samsung 32M cache memory. The controller chip is in the center—it is a Marvell chip, hat tip to this semiconductor logo page. The flash obscures the chip in the lower left, but it is also an ST Microelectronics SMOOTH motor controller. The DIP-like contacts in the upper left couple to the head assembly through a bulkhead connector. The lower-right contacts near the SMOOTH chip are for the platter motor.
The cover’s off. This wasn’t as nice a picture as the Seagate—there’s already dust on it, and I only had it off for a minute when I snapped this image! I will never do clean room work in my building, that is for damned certain.
I got the platters and the heads off. You can see the other side of the bulkhead connector I pointed out previously. Unlike the Seagate, Western Digital drives only need one Torx T2 driver to disassemble; I had quite the collection of bits used in disassembling the former.
The heads. I mashed one pair getting them off the platter but I still got a good picture:
Another picture of the heads:
It’s interesting that my Seagate has a full head arm but not all of the heads (it had 2 platters and was made for 4.)
Fortunately for my electronics, I have run out of things to tear down. For now.
I had to clean house for an inspection and had several very dead hard drives around, none of which could be sent back for warranty, so I dismantled them. Most drives are easily disassembled with miniature Torx bits which are readily available from many vendors. (here’s one such set.)
This Seagate Barracuda died in a “normal” way, its SMART data showing increasing reallocated sectors indicating slow-motion death. Its controller board is quite small:
Almost all hard drives these days use the same Samsung 32 meg cache memory. LSI is a familiar controller vendor and one of their chips is here. The ST Microelectronics SMOOTH chip is apparently a motor driver—I’ve seen it in several drives.
The drive lost its warranty due to an external enclosure and a very badly designed SATA pigtail that broke the connector on the drive. The enclosure had numerous other problems, ensuring that I will not use that make again anytime soon.
Next up, Western Digital, torn apart.
I will probably find out otherwise when I make this post, but I may have resolved my KVM RFI problem. In a previous post, I performed a teardown of my KVM and noted that the top of the unit was blank. Normally there is a name plate on the unit:
I found this plate nearby—it had fallen off the KVM. I stuck it back on. (I wanted to re-glue it, but it would not come off the unit for me.) The “IOGEAR” logo looks almost metallic. I immediately wondered whether it had a shielding function. The plate appears to be plexiglass with perhaps a metallic layer in-between where the logo is etched.
I have had both machines hooked up to the KVM for a day now and have not seen the interference that has driven me nuts for nearly three months. I hope this is it. Really.
I’ve been having some RFI problems lately with my computer setup at home. I run my workstation and server through a IOGear GCS-634 USB KVM connected to a Dell 2309W display, a Logitech Marble Mouse and a USB keyboard. This KVM is a four-input model that switches USB, VGA and audio between computers; two of the KVM cables are hardwired to the unit, the other two (which are included with the KVM) are optionally connected to the unit. I use two of the four inputs and use the others when I occasionally fix a computer on the bench.
I wasn’t certain I would find the problem just by opening up the KVM, but I seldom have the opportunity to take apart even my own electronics and I always take pictures when I do.
This is the bottom of the box. The screws are under the outside corners of the rubber pad in the center.
The circuit board:
The component side of the board:
I wonder if this is a JTAG port on the right?
I’m still looking for the RFI. At first I suspected a ground loop between my workstation and server as they are on different outlets and probably different circuits; whenever National Grid drops a phase to my building feed, only my workstation or my server will go dead or reboot, usually not both at once. However I’ve disconnected the server from the KVM and the interference still persists. I’ve measured between the ground frames of the two machines and I see no significant voltage, AC or DC, between the two (A 1V difference would be enough to warrant remediation in a typical installation.) I changed out the power cord on the server since I tend to reuse older cords—no change. I ran without the KVM for a few days and no RFI.
It only happens when the workstation is switched in on the KVM and does not appear on the server’s KVM display. It shows up as vertical waviness; when I play games, the interference is most pronounced on vertical lines and features, especially at the lower resolutions of the old games I tend to play. This points to RFI in the vertical sync line of the VGA output. You can actually see the vertical jitter on the screen at a frequency of around 5 to 30 Hz as it surges up and damps down. I had it happen while I was writing this post but it damped down just as I got the camera.
My VGA card, an eVGA GeForce GT-240, may just be unusually susceptible to RFI. It seems like it’s ringing. I wish Tek let me take their scope home the other day—I would have found the answer tout suite! I have an idea for fixing this based on an RS-232 metal dongle shell, VGA connectors, ribbon cable, caps and beads, that I will try when I get a chance.
There were booth ladies at XJtag. Again.
The tether is just for theft prevention—there is no IR emitter on this remote. Don’t ask me what happens when your Bluetooth, 2.4G cordless, WiFi and microwave are all in the same room as they are in my apartment.
The high point of ESC was the day after the exhibits when Tektronix held a seminar featuring hands-on training on their mixed-signal digital oscilloscope. My personal test instruments belong in a museum and I have never used a digital scope, though I’m familiar with the technology.
Apologies for the poor cell phone photo. The BNC jacks have familiar analog 10X probes, while the digital probe set plugs into the middle of the front panel. This scope had 4 analog channels and 16 digital channels. We plugged the scope into a special demo board that makes “bad” signals with various defects that users are trained to figure out both in the analog and the digital realms. My partner and I got through the two sessions without breaking anything and we both learned something about digital and serial bus troubleshooting. If my partner reads this, I’m sorry I went too fast for him; I have never used this scope but I wasn’t hesitant a bit to push buttons and turn dials.
I can dream about affording this scope for another day.
I did come home with some goodies:
Microchip contributed most of the items in the photograph; you can see their CD’s and chip sample card. Micrium was handing out a thick book on real-time OS (RTOS) technologies. Interestingly, Microchip has some sort of marketing agreement with Energizer, the bunny battery people. There are AA, AAA and AAAA batteries and an LED pen light. Plus a Dell yoyo that’s supposed to light up but doesn’t. I usually share this stuff at the SATV offices, but I always keep flashlights for myself!.
I always say I will get more involved with embedded work; I have a collection of dev kits I have seldom used, because they either didn’t do what I was interested in or they cost too much to get working. I’d love to find a dev kit with Ethernet that I could justify for a micro web server or preferably a NTP clock with a GPS module. They’re getting cheaper.
I had a good time as usual and I appreciated the break from my usual work. Especially the scopes.
Yesterday I was at the Embedded Systems Conference in Boston. This is a show I attend every year to learn what new technologies are going to be in the IT equipment I use. Highlight of the show was watching a teardown of the Optoma PK-101 pico projector. It’s about the size of a cell phone yet it can project images on any nearby wall. We got to see it being taken apart. The presenters were more interested in the projection technology itself—RGB LEDs feeding a TI DLP micromirror array such as you would find in a big screen TV a few years back. Here we see the projection module with its LEDs, dichroic mirrors and the DLP chip in the upper right corner.
Here it is again, in pieces:
People are paid to do teardowns! If I were 3 years old again, I would have done this at no charge! You could ask my mom if she were still with us.
Another trade show sight I didn’t think I’d see again:
Booth babes! But what are they selling, again?! (Apparently, circuit board testing.)