Computer Tech

New Toy: Kill-A-Watt Meter

Published by on June 26, 2015 | Leave a response

My household uses surprisingly little electricity during the summer, probably because we don’t run the AC much. Air conditioning is expensive, especially with an elderly outdoor furnace/AC unit that was manufactuered before Facebook was a thing. Without the AC’s 3.5kW draw, our electric bill stays nice and low most months–except when it doesn’t, for (seemingly) neither rhyme nor reason.

While investigating the months of higher electricity usage, I noticed that the house draws about 420W on average–at night. I was surprised that our baseline usage was that high, so I bought myself a Kill-A-Watt meter to see what was going on. The device is dirt simple. Suppose you have a thing, and you’d like to measure its electricity draw. You plug the meter into a wall socket. You plug the thing into the meter. You push buttons to switch between amperage, wattage, overall power consumption (in kilowatt-hours), and time since the meter was plugged into the wall. Bam. Profit.

With the last two items, you can estimate the average electricity draw over a long period of time. Dividing the total consumption (in kilowatt-hours) by the time the equipment has been running (in hours) nets you the average electrical draw over that time period (in kilowatts). This is useful for devices with intermittent load, like refrigerators.After some unscientific experiments, I got some numbers on instantaneous power draw from my old hardware:

  • LCD monitors use about 30W apiece when on.
  • Wireless routers use 3-5W of electricity when idle.
  • Wired router (a Celeron desktop) uses 45W idle and 65W when under full CPU load.
  • T43 laptop uses 5W in standby (not charging), 25W idle, and 50W under load.
  • Desktops use about 5W when off/standby.
  • i5 + nVidia GeForce 650TI box uses 45W idle and 90W playing Unvanquished.
  • i7 + AMD 6950HD box uses 99W idle (!), 240-260W playing Deus Ex: Human Revolutions, and 300W (!!) playing Bioshock: Infinite.
  • Core 2 Quad server with four hard drives uses 150W of electricity.
  • Acer h340 NAS uses 56W under full load with the case fan at 100% and all four hard drives spinning.

Immediately I spotted some things that were using far more electricity than I had assumed. The Core 2 Quad box is one. In retrospect, the waves of heat pouring out the back of the case should’ve been a hint. I took its 4 hard drives and put them in the NAS. It uses a third the current, and while its CPU is sloooooow, it does do what I need it to do, and I can accept the loss in performance. The wired router is another device that could be replaced to save. In addition, LCD monitors use more electricity than I realized; I’m making a concentrated effort to turn them off when I’m not around, or to configure their power saving modes more aggressively.

I’m going to go back and measure every device I have using a more rigerous method, noting down phantom power (draw when off), standby power (when applicable), idle draw, and loaded draw (under various CPU, hard drive, and GPU workloads). Eventually I’ll get a table of hardware set up here with various figures.

Galileo Board Temperature Sensor

Published by on June 17, 2015 | Leave a response

My independent study project turned into a full-blown research project last semester. The project involves benchmarking lots of physical and virtual machines, which means the project involves generating lots and lots of heat. My equipment is in a room that has no air conditioning on evenings and weekends. I knew it got hot in there over the weekend, but I wanted to know: just how hot did it get?

So, using the Intel Galileo Board 2 I won at IDF2014, I cobbled together a smart temperature sensor. It uses a TMP36 analog temperature sensor wired to the Galileo’s Arduino-compatible analog input pins. With the Yocto Linux image on an SD card, a little Python daemon, and some /proc filesystem flags tweaked to control the Galileo’s onboard analog-to-digital converter, I can scrape data from the temperature sensor and make it available as JSON feeds, which were then read in by another script to be processed into a HTML report. It’s a little kludgy, but it works.

You can find the actual (current) feeds of the equipment room here. A glance at the week graph shows the pattern of air conditioning availability.

I’ll release the source code and write up step-by-step instructions soon.

 

How did I even…?

Published by on June 3, 2015 | Leave a response
How did I even...?

What it says on the tin. (Click for embiggened version.)

Photo of blown supply trace on motherboard

Back of motherboard

The trace appears to be the 3.3V voltage line between the ATX connector (pin 13) and the DDR2 RAM slots on a Micro-ATX motherboard. (Edit: DDR2 does not run at 3.3V, so either it’s going somewhere else or I have no idea what’s going on–probably the latter.) I upgraded the RAM from 2x1GB to 2x2GB, but apparently in the process I also upgraded from “working-but-wonky backup server” to “dead motherboard with a side of magic smoke”.

I’ve never seen anything like it. I’ve put disassembled and put together hundreds of computers and the worst damage I’ve ever caused is a broken header pin. The only thing I can think of is the RAM sticks (which are tiny half-height sticks) may have been damaged when I pulled them from another computer, or when I installed them. One of them has a pin that is discolored and raised away from the module. Unfortunately, I don’t know if it was that way before or after the trace fried.

I’m keeping the motherboard for soldering practice.

Another photo:

blown_trace_1

Anybody seen anything like this before?

Fun With Routers, part 2 – Netgear WNR1000v2 VC + OpenWRT

Published by on March 28, 2015 | 3 Responses

Garage sales. Garage sales are awesome. I picked up a Netgear WNR1000v2 VC router at a garage sale for $5 last year. That’s a bargain, until you realize that this router should’ve retailed for $5. The stock firmware is terribad and limited. A JavaScript bug prevents WPS from being disabled unless you visit the administration page using Internet Explorer. It doesn’t help that some of these units were modified by Comcast to only accept certain firmware updates, and then passed out like candy to clueless Internet subscribers who needed a troublesome device to scream at daily. (As if dealing with Comcast wasn’t bad enough already.)

Enough ranting. Here’s the cool part: OpenWRT didn’t support it at the time. No, wait, that’s not the cool part. The cool part is, I accidentally got a custom build of OpenWRT onto the thing after investing in a USB TTL serial adapter and flailing around with OpenWRT’s source code. Wait, that’s still not the cool part.

I don’t remember how I got it working. It was towards the end of last semester, and last semester was two forevers ago in computer years. I posted on the OpenWRT forum but didn’t get any response, and I didn’t know enough about OpenWRT’s internals to submit a patch, so I slapped my hackish build onto the device and immediately forgot about it.

But! A hardworking developer who goes by the handle SaltwaterC took the time to figure out this pesky little device and made some nice builds and patches. That’s the cool part. Thanks, SaltwaterC!

If you have one of these, don’t throw it out! They actually work great with OpenWRT, especially if you can rescue one from the bargain bin at your local thrift store.

MicroTik Routerboard 411 + OpenWRT: Update

Published by on October 31, 2014 | Leave a response

The ailing Routerboard 411 in one of my previous posts has been sitting in a plastic tub under my bed awaiting replacement capacitors, a sudden level-up in my soldering ability, and a dramatic increase in my level of confidence in not destroying things by jabbing at them with a giant heating element. I still have none of the three; however, one of my friends donated his time and effort and replaced the four dead capacitors for me. (Thanks, Will! I owe you a gift card.)

Now that the capacitors have been replaced, I’ve put OpenWRT on the device for good. The instructions here are dubious. I did things the manual way according to this blog post, starting from the point after I had booted into OpenWRT’s ramdisk image as detailed in my previous post about this router.

(more…)

Fun with routers, part 1: MicroTik Routerboard 411 + OpenWRT

Published by on July 11, 2014 | 1 Response
Routerboard running OpenWRT Attitude Adjustment

My father uses a WISP for his Internet access. His equipment malfunctioned recently and a technician came out to examine the antenna. He discovered that the circuitry inside it had failed; instead of throwing it away, he offered it to me.

Meet the MicroTik Routerboard 411.

(more…)

Getting near that time of year…

Published by on May 3, 2014 | Leave a response
Auxilliary cooling
Auxilliary cooling

Auxiliary cooling

When stock cooling won’t suffice and you can’t afford a case with better airflow…it’s time to improvise.

I know, I know. Why isn’t the orange case fan plugged in? It’s not plugged in because it so happens that it’s not actually a case fan, it’s really a jet turbine with aspirations. Unfortunately, its aspirations aren’t so much of the “move hot air out of the case” variety, they’re more of the “make noise than all of my other equipment put together” variety. The desk fan is quieter and moves much more air.

It’s almost summer, yay! Time to start cleaning heatsinks.

Not much new to post.

New hardware: Mac Mini

Published by on March 30, 2014 | Leave a response

I have a Mac now. I’d say that it was my first Apple product ever, but that would be a lie because there’s a Mac Classic buried in my closet somewhere. Well, close enough, right? A friend was offering his Mac Mini (2012-ish) for a reasonable sum and I decided that my life would be forever incomplete without at least one silver aluminum unibody device sitting on my desk and driving up my electricity bill, so I bought it.

The specs:

  • 2.66GHz Intel Core 2 Duo
  • 8GB DDR3
  • 80GB Intel SSD
  • Gigabit Ethernet
  • 802.11b/g/n wireless
  • Bluetooth
  • SuperDrive (DVD/CD writer combo)
  • HDMI
  • Lots of USB ports
  • Mini DisplayPort
  • HDMI

All of this hardware is packed into a sleek 7.76″ x 7.76″ x 1.4″ silver case, which has a large, sturdy plastic cover on the bottom that twists off to allow access to the memory sticks and the single laptop-style cooling fan. Note to computer manufacturers: unfettered access to the fan for cleaning? 11/10 five stars A++++ would buy again. I don’t know where all the dust in the house comes from, but I certainly know where it all ends up: in my computers. Every spring and fall I have to grab my screwdriver and go on a rampaging marathon to coax out the dust bunnies that have taken up stubborn residence in my heatsinks and power supplies. Having the fan exposed for cleaning without even needing to remove a screw is a nice perk. Of course, the trade-off is that the hard drive is much more difficult to get to than one might expect. Win some, lose some.

So I unpacked the Mac Mini, went about hooking it up, and immediately had a Eureka moment. You know those little white dongles that every Mac-toting professor has to fiddle with to connect their Mac to a digital projector? I didn’t know what those were for, because I’d never owned a Mac and had never bothered to ask. Well, now I know. (Insert Bill Nye audio clip here.) One of life’s greatest mysteries, solved! Turns out, they’re kinda important, and by that I mean I couldn’t connect my shiny Mac to any of my monitors because none of them grok Mini DisplayPort and I didn’t have that Mini-DP to DVI/VGA dongle. Oops.

Turns out, they’re also expensive, or at least, the ones from Apple are. For a company that markets to college students, they seem not to know their target demographic very well. (Sure, not all students are strapped for cash, but then again, not all students can go out and spend $30 on a passive Mini-DP to DVI dongle when $30 can be stretched out into a decent amount of basic groceries.) Or maybe we’re not the target demographic. Maybe the Apple Store on campus is less of a store and more of a carrot dangling from a stick. Or maybe the power of a brand name is much more compelling to other people. Or maybe Apple sells more product at expensive, private colleges, and the store here is just an afterthought. I don’t know. No matter what the rationale, I wasn’t going to pay Apple prices for a DVI dongle. Monoprice sells a cheap imitation for about $10 with shipping. It gets the job done and hasn’t broken (yet), so I bought that instead and now I have $20 left over to spend on more important things, like ice cream.

So I booted up the Mac, logged in, and started exploring. I was expecting another Eureka moment here. I was expecting at any minute to find some fundamental way in which Macs differ from their PC counterparts, but I haven’t found one yet. Yes, Mac OSX is odd, but it’s odd like a new keyboard or a different brand of peanut butter; it’s something that doesn’t take very long to get used to. The operating system is very easy to learn, especially if you grok another UNIX (or UNIX-like) operating system.

Some thoughts:

0) Mouse movement is so smooth!

1) I found out later that it uses only about 10W of power when idle. Whaaaaaaaaat. It also runs very cool and quiet. I can’t hear the fan unless the Mac is doing some serious number crunching.

2) This was the most powerful piece of computing hardware I owned until I put together my Windows 8.1 PC a few days after I got the Mac.

3) I have to question the wisdom of putting a 802.11 wireless card and a Bluetooth receiver inside of a metal case. Yes, the bottom and back of the Mac Mini are plastic, but if you’re like me and you set it on top of a metal desktop tower in the corner…oops. Fortunately, I don’t need the wireless capabilities. I just jacked it into a gigabit LAN.

4) I feel like I now own a status symbol. Not the Mac itself, but the dongle. It forever brands me as a Mac user. Sure, a few other manufacturers have started using Mini-DP, but by and large, they seem to be associated with Macs.

5) This is the first time I’ve ever owned all three of the “modern” desktop/server platforms. I have Windows PCs (7 and 8.1), Linux servers, and now, a Mac desktop. Embrace the diversity! When Skynet comes and takes over all the PCs, we’ll be able to fight back with the Macs!

Acer H340 NAS

Published by on January 20, 2014 | 6 Responses
Resistance is Futile

Edit 12/15/2014: Ooops: the Atom Z230 is a hyper-threading single-core CPU, not a dual-core. I noticed this a few months ago but haven’t gotten around to updating this post until now.

Several months ago, a friend gave me an Acer Aspire easyStore H340 NAS. The system hard drive had failed and up until recently I haven’t had any spare SATA drives, so it collected dust on top of my desktop computer until I could find a drive for it.

Resistance is Futile

Resistance is Futile

The stock H340 has the following:

  • 1.6GHz Intel Atom 64-bit dual-core CPU
  • 2GB DDR2 RAM
  • 4x SATA 2.0 hard drive bays
  • 1TB Western Digital Caviar Green hard drive
  • 1x Gigabit Ethernet port (Marvell chipset)
  • 5 USB 2.0 ports
  • 1 eSata port
  • 1 PCI-E 1x connector (not used).
  • Windows Home Server
  • Onboard 256M flash device containing restore image for the OS (although it seems to need a driver/application DVD as well).

All in all, a capable little device, especially for the low, low price of free. It sits in a case approximately 10″ square. Air is drawn in from the left side, across the hard drive bays and over the motherboard at the bottom of the case, and exhausted out the right side by a 120mm fan. Notably, there is no video connector–which makes sense, considering it’s marketed as a headless NAS. Still, this is limiting, although there are several companies who make VGA/PS2 dongles that connect to a proprietary connector, and the PCI-E slot could be used for a PCI-E 1x video card.

Lacking the WHS restore disk, I decided to put Ubuntu Server on the H340. First, I did a little research to find out if this device will boot from a USB flash drive. It will, but not by default; the jumper JP3 on the motherboard puts the NAS into “debug” mode, which allows you to change the boot order in the BIOS–except I couldn’t see the BIOS, because there’s no video card connector. Ooops. So I went with the considerably less exciting route and installed Ubuntu Server on another computer, then transferred the hard drive to the NAS.

With JP3 jumpered (in debug mode), the device seemed to ignore the hard drive and booted into some sort of rescue/recovering environment with a hostname containing “minint”. I suspect this is what is contained on the onboard 256M flash device. Once I removed the jumper on JP3, restoring the NAS to stock configuration, it booted right up. I installed Samba and several minutes later had a simple file server set up and running.

Some thoughts:

  1. If you set up Ubuntu Server on a second computer, you’ll want to remove the entry in /etc/udev/rules.d/70-persistent-net.rules such that the NIC in the NAS (there’s some alliteration for you) will be detected as eth0 and not, say, eth1. You’ll also want to have OpenSSH set up so you can SSH into it after installing the hard drive.
  2. You’ll probably want to install lm-sensors and smartmontools to keep an eye on temperature and hard drive health. I also installed logwatch and configured it to email my LAN’s mailserver.
  3. The power supply fan (a tiny 40mm fan on the back of the proprietary power supply) is noisy. I suspect this is specific to my used H340 and not common to all H340s.
  4. The side fan is reasonably quiet. However, once it boots, the motherboard throttles the fan down to 700RPM. CPU temperature idles around 63-65C in this configuration. The fan speed can be adjusted either manually or via a script (such as fancontrol). I have mine set to about 1100RPM, which lowers CPU temperature by 4-6C while keeping the room quiet enough for me to sleep at night. It also helps cool the hard drive(s)–and cooler hard drives tend to be less troublesome.
  5. The hard drive LEDs and the “i” front panel LED need a driver to control them. Fortunately, someone has written one called mediasmartserverd. Among other things, it enables the drive lights and allows you to control the brightness of all the LEDs–useful for sleeping in a dark room. It also allows you to control the “i” LED and use it as an indicator when operating system updates are available. (This feature may be Ubuntu/Debian specific.) The color scheme is as follows: blue == updates available, purple == security updates available, red == reboot needed (after updates are applied). Note that it is godawful hard to differentiate between purple and red when the brightness is turned down low; the purple looks very much like red.
  6. The H340 is adorable. I like the form factor.

To control the fan and start mediasmartserverd, I put the following in my /etc/rc.local, just above the “exit 0” line:

# warning: I don't really know what this is doing
# put the fan into user-controlled mode (?) default is "2"
echo 1 > /sys/devices/platform/dme1737.2160/pwm1_enable

# allow root to adjust the fan speed
chmod u+w /sys/devices/platform/dme1737.2160/pwm1

# echo a value between ~100 and 255 here. 
# corresponds (somewhat) to fan speed
# If it's too low, your drives/CPU may fry!
echo 130 > /sys/devices/platform/dme1737.2160/pwm1

# start mediaserverd, adjusting LED brightness and update checks
/usr/local/bin/mediasmartserverd --brightness 3 --update-monitor -D

Remember, overriding the motherboard’s fan control is risky. I’m making it run faster than it does by default, but a typo could cause it to run slower or not run at all. Be careful. You don’t want to fry your hard drives!

All in all, I’m pleased with this little device. It’s not the fastest server in the world, but it’ll get the job done, and for me, that’s all that matters.

It’s also cute. Just pointing that out…

I’m surprised this box still runs…

Published by on September 13, 2013 | 2 Responses
I'm surprised this box still runs...

It’s been awhile since I’ve dealt with the capacitor plague. I recently inherited this elderly (1.8GHz Pentium 4, 1GB SDRAM, 40GB hard drive) box from a friend who is now happily rocking out with a new computer powered by a much more modern and power-friendly dual-core AMD CPU. Naturally, the first thing I did (after cackling and rubbing my hands together with glee) was to open the case and shove the ribbon cables aside. Oh. Hello.

I’m surprised it still runs. In fact, as far as I can tell, it runs as steady as a rock, although how a rock can run is beyond me. (After all, a rock has no legs.) Of course, if it had been some of the larger caps near the CPU, it probably wouldn’t be running very long at all.

Time to pull out memtest86+ and prime95.

caps

“When Caps Go Bad…”