Tuesday, May 25, 2010

Moka Pot

I was having breakfast at a friend's apartment when I found what is quite possibly the most entertaining kitchen gadget I've seen in a long time.  I was poking around her counters when I saw this (And yes, that's a full size electric range, so it's really that small):
 A search on Wikipedia later, this apparently a moka pot.  She had gotten it from a neighbor moving out, and had not yet figured out how it works.  Being the engineer I am, how could I not see that as a challenge?  I found the entire operation of it very entertaining and clever, so I thought I'd share it with all of my readers. (And I promise, more actual technical posts on electronics and such are coming, they just require free time for me to do technical things first)

Opening the pot revealed three sections:
 The top section with a pour spout and a column from below that has a defused notch on the top.
 A middle section with a fine grating
 And a bottom section with a tube leading into the middle section and what appeared to be (and is) a pressure relief valve.

Operating this is fairly simple.  Finely ground espresso beans are added to the middle section, and water is added to the bottom section.  There is a gasket between the bottom and top sections, which screw together.  As the water boils, it pressurizes the bottom section, forcing the water up the tube, through the grounds, and up into the top section.
Once all of the water has been forced through the grounds, the moka pot makes a distinctive bubbling noise as the bottom section depressurizes, at which point the espresso can be poured into the most adorable mug you can find in your kitchen, and enjoyed with breakfast.
Oh, why yes... That is a little ceramic cow taking a bath in my espresso.

Unfortunately, I had so much fun watching it brew that I managed to make quite a mess on her kitchen range, as well as having three espressos with breakfast, which quite thoroughly precluded getting anything that required concentration done for the rest of the day.

Sunday, May 16, 2010

Using an 8GB CF Card in a Fujifilm S7000

This is for anyone else searching for how to solve this problem.  I bought an 8GB Compact Flash card to use with my nice digital camera, since it only had a 256MB xD card in it.  The camera I have is a Fujifilm FinePix S7000, which is a VERY nice camera, besides its one shortfall of being so big, which is of course also why it's so nice.
I bought the 8GB CF card without doing too much research as to if it will actually work or not with the S7000.  It turns out, at first glance, it did not.  It turns out the S7000 uses the FAT16 file system on its memory cards, as opposed to FAT32, which is what most modern SD cards and USB flash drives use.  This means that the file system on this camera can only support 2GB partitions (anyone remember Windows 95 with the hard drive split into 5 different partitions? Good times...), so the camera complains of an uninitialized card, but formatting it through the SET menu does no good.

So the problem is that the camera can't handle cards bigger than 2GB.  Fortunately, I realized that with a little partitioning magic, I could most likely trick my camera into thinking that this card really only was 2GB, at the expense of leaving the other 6GB unused, for now.

The solution I used to fix this was to pull out my trusty Ubuntu boot CD and booted it on one of my computers to use the wonderful tool called GParted.  GParted lets you edit the partition table of any storage device, which means you can destroy a lot of data very quickly, so don't say I didn't warn you.  (GParted apparently also comes on its own boot disc if you don't happen to have an Ubuntu CD laying around.)

Using GParted, I deleted the 8GB FAT32 partition, and created a 2048MB FAT16 partition.  Note that GParted will let you create a FAT16 partition up to 4GB, but anything larger than 2GB (2048MB) won't work with the camera.  Click the apply button, and you can now use the CF card in the S7000.

Obviously, this is less than ideal, since it means than you can only use two out of the eight GB on the card, but since I had no other use for the card than for this camera, its 2GB more than I had before.  If you ever end up using the same card in a more modern camera, you just have to follow the same process to delete the 2GB partition and create a new partition that is the full size.

Tuesday, May 11, 2010

Quincy Railroad #3 - 44 Ton Switcher Locomotive

This previous weekend was crew training up at the Western Pacific Railroad Museum, so my dad met me in Davis Friday night, crashed on our futon, then 5AM Saturday morning the two of us took off for Portola.  After spending the morning sitting through the annual safety training class, I spent the afternoon getting my hands wonderfully dirty.

The assignment for the afternoon was to fill the Quincy Railroad #3 locomotive (museum roster page) with water and antifreeze.  QRR3 is a GE 44 Ton locomotive, which was specifically designed and built for light industrial use during the 1940s and early 1950s.  The museum is trying to get this locomotive back in service for a very similar purpose.  The lower power engines in this locomotive use less fuel than most of our larger locomotives, so to be able to use this for most of our light-service requirements will hopefully save the museum quite a bit of money.

Filling a locomotive's radiator system is much like filling the one in your car, except that everything is just bigger, so instead of buying antifreeze in quart bottles, we buy it in 55 gallon drums and use a forklift to get it into position.
So the assignment was simple: Create a mix of 50/50 water/antifreeze such that this locomotive can be kept in service during the cold pre- and post-summer work, while most of the other locomotives must be drained of their coolant to prevent freeze damage.  This locomotive is powered by a pair of Caterpillar D17000 V8 diesel engines, so the priority was to get at least one of them operational, since even just that would be sufficient for what we need around the museum.
Luckily, before we started filling the radiator with $150 worth of antifreeze, we got the crazy idea of filling it just with relatively cheap water and check the system for leaks.  This turned out to be fortunate, since once we filled the radiator, the entire engine started leaking like a sieve.  The antifreeze was subsequently kept in the barrel it came in and put away.

Upon closer inspection, it appears that pretty much every rubber hose and gasket in the entire system is at least dried out, and many cracked.  All eight piston heads leaked water around the main head gaskets, which appears to have been replaced at some point with Form-A-Gasket, which doesn't bode well.
All eight heads leaked about this bad.  Might all of these leaks get better once the dried out rubber softens up? Maybe a little, but I'm afraid it's likely this engine will continue to significantly leak water until we tear down the heads and replace (and by replace, I mean actually install) all of the gaskets and replace all of the rubber hose connections.

Less fortunately, it appears that this engine suffers from an additional leak which isn't rubber-based.  On the side of the engine (below the #4 cylinder) is a heat exchanger between the water and fuel system.  Our theory is that it is used as a fuel pre-heater (does anyone have any additional information on this exchanger? Can we bypass it?).  In the picture below, it's the box below the exhaust valves and to the left of the red wire.
On the left side of the exchanger is a large (2 inch) unthreaded hole which started pouring water after the inside of the exchanger finished filling up.  This means it seems likely that at some point water got trapped in the coils of this exchanger and froze, fracturing the coils and creating this leak.
This means that as far as getting this locomotive in service in the short term is not looking very good.  With this many water leaks, running this locomotive will require refilling with water at least daily, possibly more often.  The fact that it appears that more than just rubber is damaged means that repairs will not only be labor intensive, but possibly very expensive.

On the bright side, the fact that the radiator system can at least retain some water means that we can start firing it up and look for the next set of problems, most likely in the electrical and pneumatic systems.  Please feel free to make a donation to the museum to help support this and other restoration projects which I and many other volunteers are working on.  This museum is the reason why I'm a mechanical engineer, but I can't support them without funding to buy the parts and supplies I need to move forward.

Update from Seth A (5/18/10):  "We got the No. 1 engine to fire up over the weekend. It leaks like a sieve, blows exhaust out of the crankcase breather but all in all runs pretty well. It moves too, except the batteries aren't getting a charge. And the train brakes don't respond to the regulator valve. The photo you have of the head, is actually the cylinder rocker arm cover. I didn't notice any water coming out of the head area."

Thursday, May 6, 2010

Moss Terrarium

I know that once Lifehacker covers it, almost the entire internet knows about it, but I still found the idea of a moss terrarium quite appealing.  It means that I can have at least some greenery in my room, without the requirement that I keep my blinds open for sunlight or stay on top of watering it regularly (Succulents are also good for this, but I've already had those for a number of years).  It's not shown in any of the pictures, but I capped the mason jar to try and keep the humidity higher, and keep the maintenance requirement lower.
I collected the moss just from around my apartment complex, and a little from one of the plants I got for free on Picnic Day.  If I had it to do again, I'd make sure to put some rocks under the dirt, and I'd have made sure the jar was really clean before I started.  Small neck terrariums like this are an uphill battle against keeping the glass clean, so starting with anything less just makes your job harder later.

Saturday, May 1, 2010

Ethernet Hardware in the Works

One thing that I have always wanted for my electronics projects has been a way to connect them to the internet, if not at least the rest of my local network.  I know that there are breakout boards and the such for ethernet, but I just didn't feel like paying $45 for something I could build for half that.


Video:


I have tested it with firmware I found online, but that's all I'm going to use other people's code for.  I think developing my own IP stack from 802.3 up sounds like a fun challenge, so this project is going to take a lot of work.

Parts list:
  • 9 contact female header for digital I/O
  • 28 pin DIP socket
  • 4 49.9ohm 1% resistors 
  • 1 2.32kohm 1% resistor
  • ferrite bead
  • a few 0.1μF bypass caps for power filtering
  • 10μF capacitor for the internal 2.5V regulator
  • 25MHz crystal
  • LEDs + 100ohm resistors
  • ENC28J60 ethernet controller (Microchip)
  • 8P8C connector with on-board magnetics (Digikey)
  • Breakout board for the 8P8C connector (Electroboards)
  • Perf board (I used Radio Shack 276-148, but it was a little tight)
And I finally got batteries for my old (yet nicer) camera. Can you tell?  The video is still taken with my new one...