Star Tracker calculator

This little snippet will assist in calculating critical numbers for building a star tracker (aka "barn door" or "hinge" tracker).

Instructions: Fill in any 3 of the 4 values below and click "Calculate". The fourth value will be displayed.
To recalculate, clear the value you want computed and change the other three.

Motor speed (RPM - Revolutions per minute)

Drive rod thread pitch (Threads/inch or Threads/mm)

Gear ratio (motor gear teeth / drive gear teeth)

Distance from hinge pin center to drive rod center (inches or mm)

DIY backpacking gear - Tyvek bivy bag

Tyvek bivy bag in "sleep under the stars" mode

Bivy bag in "inclement weather" mode

Every time I go backpacking, I keep thinking - "What more can I do to lighten my load?".  Because I live in Southern California and many (most?) trails don't have reliable year-round water supplies, we're forced to take large (heavy!) supplies with us, so the more we can lighten the rest of our loads, the better.

This time out, I was after lightening my 4 lb. "shelter" (tent and footprint), using a DuPont™ Tyvek® sheet made into a bivy bag.

Advantages:

• Lighter - bivy bag and groundcloth is 1.5 lb., vs. 4 lb. for my 1-man backpacking tent & footprint.
• Warmer - because it's such a tight weave and is so close to you, it traps body heat much better than a tent.  Claims of an extra 5°-10° F are probably not unrealistic.
• More compact - folds up smaller than my 1-man tent and footprint.

Parts list:

My Tyvek was shipped in Tyvek!
(good for small scraps)

• 1 9'x12' Tyvek sheet (~ $25.99 on eBay), available from various sellers on eBay - this is the one I used and can highly recommend.  If you don't need a Tyvek groundcloth, you can get a 9'x8' sheet.
  
  Also, I used the standard "house wrap", mostly because that's what I saw more recommended by others.  But some use the Tyvek 1443R "soft structure", which is lighter softer and quieter, but more expensive and more difficult to find in the necessary size.  I was a bit concerned about its water resistance, since I plan to use this bivy by itself, without a tarp.  If you make one from this fabric, please let me know in a comment how it works for you...
• 1 roll Tyvek tape ($12.50 or so from eBay)
• 2 36" robe zippers ($2.99 each at Joann Fabric and Crafts).  You can use most any 36" zipper; this was the only one I could find locally.
• 1 5' length of 1/4" PEX pipe ($1.76 at Lowes)
• 1 2" piece of double-sided Velcro ($4.99 for 25 8" strips at Joann Fabric and Crafts)

My pattern
(click to enlarge)

Assembly Instructions:

1. Make yourself a pattern.  I used this (dimensions are in inches), but you'll probably want to change the dimensions to fit your bag, height and girth.  I'm 6'5" and have a very long bag, so I made mine using the full 9' length of the Tyvek.  If you're shorter, you can trim to make it smaller and save some weight.
2. Knead and/or wash the Tyvek to soften and quiet it.  There's differing opinions on the 'net as to whether it's better to soften the Tyvek before assembly or after.  I chose to soften first (both by kneading the dry material by hand for 10 minutes or so and then putting in a washing machine (with no detergent or fabric softener, water only!) for a full cycle.  This has no impact on its water resistance.  Note that doing this will "shrink" the Tyvek by a few inches in both directions, so if you plan to wash after assembly, be sure your pattern is upsized to accommodate this.  Mine shrank from 12' to 11' 4" and from 9' to 8'5" or so.
3. Using your pattern, mark your cut points on the Tyvek, using either a pencil or fine-point permanent marker.  A yardstick can help keep the lines straight.
4. Make your cuts.
5. Attach the vertical zipper.  Set your sewing machine to use the longest distance between stitches.  You'll need to cut a 3/8" slit on both sides at the end of both zipper cuts in order to fold back 3/8" of Tyvek.  This makes an opening for the zipper and allows you to sew through two layers of Tyvek, making a stronger attachment.  Take your time, this is probably the hardest step.



Zipper detail
(click to enlarge)

6. Attach the horizontal zipper.  If you got a single-sided zipper, like me, you'll want to attach this one with the pull tab on the inside of the bag, to make it easy to open from the inside.
7. Using the Tyvek tape, seal all of seams of the bag.  You can do it in most any order, I opted to tape the long vertical seam (above and below the vertical zipper) first, followed by the top and bottom of the bag.  I opted to put about 1/4" of Tyvek overlap on all of my seams (with the overlap coming from the top of the bag, to keep any rain out that might get under the tape).
8. If you want, turn the bag inside out and put a layer of Tyvek tape on the inside of all of the seams.  This will help strengthen the bag and keep the overlapped flaps from catching on anything inside the bag.
9. Get inside of the bivy with your gear and the PEX pipe.  Figure out where you want to put the pockets for the ends of the PEX pipe and where you want the Velcro strap.  Mark the locations with your pencil or marker.
10. Make pole pocket by taking a 1/2" x 1-1/2" piece of Tyvek and placing it vertically in the middle of a 3" piece of Tyvek tape. Place it centered over the mark you made in the previous step.  Repeat for the other side.
11. Cut off a piece of Tyvek tape 1/2" x 2".  Use it to attach the velcro strap to the marked position on the inside of the hood.
12. Cut the PEX pole as needed to fit inside of your bag.  I needed to trim about 6" off of mine - you may want more or less.

Velcro strap
holding PEX pole
(click to enlarge)

PEX pipe inserted
into pole pocket
(click to enlarge)

OpenSprinkler Pi - smart sprinkler timer review

Due to the ongoing California drought, I decided to upgrade my old Toro sprinkler timer.  Some of the things that I wanted out of a new unit included:

• Weather "smarts" - ie. the ability to lengthen watering during the hot months, shorten it during the winter and turn it off completely when it's raining (or will rain in the next day or two).
• Logging capability - I want to see how much water I'm using on my lawn (our department of water & power bills sewer charges based on how much water is consumed - which isn't ideal if 75% of your water usage goes into your landscaping and not down the drain.
• Remote control - the ability to view and control the system from afar, preferably using a web- or smartphone-based system.

 With these requirements, run-of-the-mill sprinkler timers from your local hardware store are out of the question.  The only commercial offerings are "smart" units, aka Weather-based Irrigation controllers.  The good thing is that many qualify for rebates.  The bad thing is that all that I could find are ridiculously expensive - starting at well over $200 and going up from there.  And most didn't satisfy one or more of my other requirements above.

The OpenSprinkler Pi controller

What to do?  I'm a tinkerer and a Linux aficionado, so I starting thinking - is there a way to make a Linux-based sprinkler contoller?  After some Googling, I came across the OpenSprinkler project.  A great idea, but Arduino-based.  I have no experience or expertise in Arduino systems.  But wait - the same guy now has OpenSprinkler Pi - a Raspberry Pi-based version.  Perfect!  He even has users who had written a number of programs to control the system in various ways - using your SmartPhone, using Google Calendar, using the web, and more.

So I ordered the parts:  The OpenSprinkler Pi 1.4 kit, a Raspberry Pi model A and a tiny USB WiFi dongle.  Total cost was around $150.00 Everything showed up within a couple of weeks and I set about assembling the unit.

Assembly: 

Quite quick.  Everything necessary is included - no soldering required.  Just mount the Raspberry Pi on the OpenSprinkler board with the included screws.  Then attach the WiFi dongle to the USB port.  I reused the power supply from my old Toro controller, which saved a few dollars.

A pleasant surprise when I received the OpenSprinkler Pi kit was that Ray had thoughtfully included a MicroSD-to-SD card adapter that allowed a MicroSD card to be used without having to cut the OpenSprinkler Pi case.

That said, I personally am not a fan of his new "one-size-fits-all" case.  Basically, he custom-designed a case for his original OpenSprinkler (Arduino-based) system.  It's great for that, but then he decided to shoehorn the Pi-based version to that case.  In order to make everything fit, he redesigned the PC board so that the Pi mounted at an odd angle.  But all of the connections were in different places, so few of the holes in the case are used for their original purposes. And because there's no display on the Pi-based system, the prominent display slot used on the Arduino-based system is covered with a piece of adhesive-based white paper.  It works fine, it just doesn't feel professional, and isn't something I'm proud to show to others who might be interested.

Testing:

Ray recommends testing the power output on the OpenSprinkler Pi board before attaching the Raspberry Pi to it.  I did so using a Volt/Ohmmeter (VOM) of mine and it tested fine with the Toro power supply.

I downloaded the software image from Ray's website and put it onto an 8 GB MicroSD card that I had laying around.  I decided to use Rich Zimmerman's excellent sprinklers_pi program, which seemed to be the most feature-complete and also provided a way to use the information from my personal weather station on Weather Underground to adjust watering times.  Cool!

One small issue I ran into:  Rich designed his software to designate Zone 1 as a pump controller (for those on wells).  So if you're not using a pump controller, you should leave Zone 1 unused.  If you have 8 zones to control, there's a workaround.

Operation:

Sprinklers_pi graph example

It works, and works well.  I'm able to see graphs showing how much time each zone is turned on, I can control the system via a web interface from home or away, I can choose to use Internet-supplied weather information to adjust my watering schedules (or not), and I can parse the sprinklers_pi log
files to keep track of how much time each zone is being watered.  Now I just have to figure out how many Gallons Per Minute (GPM) each zone uses, and I should be able to determine how much water is going into my lawn each month.


All in all, I'm satisfied with my new smart system, even if it didn't qualify for a rebate...   ;-)  I just hope he decides to redesign his case into a true all-in-one solution for all of his OpenSprinkler options (Arduino, Pi and BeagleBoard).

2010 Motobecane Grand Sprint Apex review

Motobecane Grand Sprint Apex

After 2-1/2 years and over 5,000 miles I think it's time to do a review of my 2010 Motobecane Grand Sprint Apex.  I live at the top of a 400' climb and at my age (somewhere north of 50), it was getting hard to climb that hill on my mid-80s vintage 10-speed.  I decided I needed something lighter than 30 lbs. and with lower gears.  Fortunately, the SRAM Apex had just started making its way to the marketplace.  With a 32-tooth rear and a 36-tooth front, I was getting the lowest gear ratio available in a  compact double road bike.  Not mountain bike low, but definitely better than the 28-42 on my KHS 10-speed.  At 6' 5", I'm a tall guy (and at 215 lbs., a Clydesdale at that), so getting a bike to fit and be strong enough was no small task.

I contemplated going with a local bike shop's (LBS) offering, but almost nobody had an Apex-equipped bike available yet.  BikesDirect.com, the mail-order dealer for Motobecane in the USA, had the Grand Sprint Apex on their website, with a pre-order price of $899.00.  It looked like a great deal, so I decided that I'd try being my own mechanic and ordered one in the largest frame size they had available - 62cm.

After a few impatient weeks of waiting until they got their first shipment, my shiny white bike showed up in early September 2010.  I think it took about an hour to assemble from box to first ride, with only a few hand tools required (Allen wrenches, an adjustable wrench and screwdrivers, IIRC).

First Impressions

The most immediate impression I had was that this bike had a different geometry than my mid-80s KHS 10-speed.  I had to lay out a bit more (not great for my back) and it felt a bit weird to be gripping the drops so far forward.  I wound up turning the Ritchey stem over, which raised the handlebar height about an inch, and also rotate the bars so that the brifter hoods were higher in the air.  Aaahh, much more comfortable...

After a few rides, some other impressions came to light:

• This bike is light - even in the 62cm frame size, it weighs almost exactly 20 lbs. (as measured by an electronic luggage scale) with pedals and a water bottle cage attached.  I was used to 30+ lbs., so this bike was much easier to pedal fast on level ground and much quicker to react when turning.  I wouldn't call it twitchy, just really quick.
• Originally, I thought the Skye Racing Turbo seat didn't have enough padding for long rides, but after using it for 6 months, I was convinced otherwise.  I'm still using it, and it's been on a number of 50+ mile rides.  It gets a little uncomfortable after 3+ hours in the saddle, but I suspec they all do...
• The brakes worked really well.  That was one of the problems with my KHS - the old side-pull brakes couldn't be adjusted to stop well and yet not rub on the rim when not braking.  So you had to either settle for constant rubbing, or long stopping distances.  The SRAM brakes stopped short and true.
• The Vuelta XRP Pro wheels were really true.  I'd never been on a bike which had such true wheels.  And they spun forever... (and they're still true, and still spin forever, BTW)

What's gone wrong

There has to be a downside (or three), right?  For me, not really.  Here's what I've had to modify/fix/change/repair in the past 2-1/2 years and 5,500 miles:

• Spokes - I broke a spoke on the rear wheel at about 3,000 miles.  A word of advice - contact the team at BikesDirect.com and ask what size spokes are on the bike.  I measured, but got the wrong size (twice) before I learned that one.  BikesDirect.com sells replacement spokes for these wheels, but few others do.  They're a black, flat-sided "aero" spoke - not widely used.
• Derailleur hanger - I dumped the bike in January.  Seemed like a pretty innocuous crash, only doing about 10 MPH and I just kinda "slipped" off the side with the front wheel hit a chunk of asphalt when I was riding no-handed.  But it bent the aluminum derailleur hanger (which, I've since found out is designed to bend/break in order to protect the frame from damage).  I was able to straighten out the hanger and adjust the rear derailleur back into alignment.  But just a week ago, I realized that the bolt which holds the hanger to the frame had come completely off and was lost.  Apparently these are typically bike-specific.  I e-mailed BikesDirect and was told that they use a "single-speed chainring bolt" to attach the hanger to the frame, which should be widely available.  I checked 5 local bike shops - none had them!  So now I have some on order from the 'net.  By the way, BikesDirect does sell replacement derailleur hangers, in case you crash badly and the hanger does its job by sacrificing itself to save your frame.  $20.99 is the current price.
• Tires - The stock Vittoria Zaffiro IIs lasted about 1,800 miles with a Clydesdale riding on them.  I liked them, but decided to try some others.  Suffice to say that as I type this, both tires on the bike are Zaffiro IIs again.  There are doubtless better tires out there, but these are inexpensive (<$20.00 each) and last well.  They could have better puncture resistance, though.
• Tubes - gone through many, due to punctures.  But it's not the bikes fault...

That's pretty much it.  No broken cables, no broken chains.  The seat's still working fine, the bar tape is still OK.  Oh, just a couple of nits to pick...

• The front derailleur occasionally mis-aligns the chain - usually by putting it over the top of the big ring.  It's not tough to put back, just annoying when it happens.
• White paint is tough to clean and shows everything.  But I like the paint scheme, so I have no plans to change it.

In the end, if I ever decide to get another bike, I'll put BikesDirect and Motobecane way up on my list.  I've been impressed with both.

 

No I'm not a BikesDirect shill...

It seems like in almost every thread you read that has a positive review of a Motobecane bike, someone accuses the reviewer of being a BikesDirect employee or a shill for the company.  I can assure you that I'm neither.  If I don't like something, I'll tell you.  Heck, I wish the bike was available in a 64 cm frame.  I wish it was 2 lbs. lighter and $200 cheaper.  But the level of components you get for the price you pay just can't be beat, in my opinion.  You just have to feel comfortable with dealing with mail-order and assembling your own bike.  The choice is yours... 

Update: June 2014

Another year on, and I'm still completely satisfied with the bike.  I managed a 70+ mile ride on it in May of 2013 (with over 4,500 feet of climbing), my longest ride ever. I fell in October of last year (my fault, not the bike's) and did some damage to my back, so my riding has been somewhat curtailed since then.  But I'm now up to over 6,900 miles on the Motobecane.  No additional parts have been replaced other than those mentioned above (and a tire and a few tubes of course!).  In particular, I'm still on the original chain, brake pads and shifter & brake cables.

Update: November 2017

This will probably be my last update, since I'm no longer riding anywhere near as much as I have been the past 7 years or so.  But the Grand Sprint Apex now has 10,000 miles on it and is still on the original chain, brake pads and shifter & brake cables.  Here's a list of everything I've replaced in those 10,000 miles:

• Rear derailleur hangar (broke when I fell, doing its job and saving the derailleur itself)
• SRAM Apex idler pulleys - both cracked at about the 6-year point
• A few spokes - mostly because I kept hitting potholes at high speed   B-(
• Lots of tires and tubes

I've been particularly impressed with the Vuelta XRP Pro rims - even with the banging they've taken, they've remained remarkably true, with only minimal truing needed after breaking spokes.

If I were going to replace anything else, it would probably be: a) the seat, as the foam is getting a bit squished down and just isn't as comfortable anymore (but then, it might just be my years catching up to me), b) the grip tape and c) the small chainring in front (it's gotten a LOT of use and some of the teeth are getting kinda worn).

In all, I'd definitely score the Grand Spring Apex a 9+ out of 10, both for value and durability.

Happy riding!

Cree 60w warm white LED review and comparision

Background

We've been using CFL bulbs for a number of years.  The good new about CFLs is that they use less electricity than incandescent light bulbs - typically about 1/4 as much.  Their pricing is less than LEDs today, but still more than incandescents.  But they have a number of disadvantages, too:

• The quality varies greatly from brand to brand.  The off-brands may be cheaper, but typically exhibit most of the bad points listed below.  And even the top-tier brands exhibit some.
• They're slow to reach full brightness - often taking a minute to more than 10 minutes(!) to get close to full brightness.
• They get dimmer with age.  The cheap brands in particular seem to lose about 1/3 of their brightness after a couple of years.
• Their lifetime is significantly shortened by repeated on/off cycles.  Yes, they may last 25,000 hours if left on all the time, but in a room where they're turned on & off a lot (a bathroom, for example), they might last half as long, if that.
• They contain mercury, which makes them a hazardous material and thus they require special procedures for disposal.
• Early CFLs were very "cool" - they had a color temperature in 5,000° Kelvin range, so their light had a distinctive bluish cast, unlike incandescents, which are typically much "warmer" (3,000° Kelvin or so) and cast a more yellowish light.  Current CFLs are available with a "warmer" tone to them, but you have to look for them.
• Early CFLs were not usable in dimmers.  In fact, they would typically be destroyed by such use. There are special "dimmable" CFLs available now, but they're typically more expensive than the non-dimmable units and are often not "full range dimmable", meaning that if you try to dim them all the way, they'll typically turn off at around 40% brightness.

So with all of that in mind, I've been looking at alternatives.  LEDs are a better technology, IMHO - hazardous material-free, even more energy conservative than CFLs and most are dimmable.  But they've typically been pretty expensive ($30-$40 for 60 watt equivalents, $50+ for 100 watt equivalents).  Because they typically need heatsinks to cool their electronics, they've often been designed in unusual shapes, many of which are either aesthetically displeasing, or won't fit in many places where A-type incandescents do - table lamps with harps or lampshades which clip onto the bulb, for example.  Early CFLs had similar issues, but most are now packaged to be closer in size to traditional A bulbs.

Cree 60 watt equivalent LED

Cree just introduced a line of inexpensive 40- and 60-watt equivalent LED A-style light light bulbs about a month ago.  What makes them relatively unique in the market is their price.  Home Depot is selling them for $9.97 for the 40-watt and $12.97 for the 60-watt.  They've been getting good reviews elsewhere on the 'net, so I rode down to my local Home Depot and picked one up to try.  I pulled a couple of CFLs out of lamps (one 60-watt equivalent, one 100-watt equivalent) as well as a 60-watt incandescent to serve as the "standard candle".

The bulbs used in this comparison - L-R:
GE 26w dimmable CFL, Generic 20w CFL,
Cree 9.5w LED, GE Long Life 60w incandescent

Statistical comparison

Lighting technology comparison

Type of bulb	Equivalent Incandescent watts	Measured Watts	Measured VA	Measured Power Factor
GE Long Life White 60 watt incandescent	60	57	57	.99
GE 26w Dimmable CFL	100	25	36	.67
Generic 20w CFL	60	20	40	.50
Cree 9.5w Dimmable LED	60	8	10	.74

As you can see, the energy consumption of the LED is less than half of either CFL and only 1/7 of the incandescent!  You can also see by the Power Factor rating that the generic CFL is of inferior quality to the brand-name unit.  It's basically less efficient.

Now on to what you want to see - the pictures.  What about light quality?  Color?  Intensity?  All of the shots below were taken with a Canon EOS T3i set to manual exposure, 1/125 at F4.5 to ensure that they are as comparable as possible.

Pictures

Floor lamp

GE Long Life White 60 watt incandescent

GE 26 watt dimmable CFL
(100 watt equivalent)

Cree 9.5 watt dimmable LED
(60 watt equivalent)

You can probably see that the 100-watt equivalent CFL is somewhat brighter than either 60-watt lamp, but the color of the LED more closely matches that of the incandescent.  All were roughly similar in color temp - I'd call it "warm white", probably in the 2,800°-3,200° K range.

Table lamp

Cree 9.5 watt dimmable LED
(60 watt equivalent)

Generic 20 watt CFL
(60 watt equivalent)

In a table lamp (sans shade), the light color and intensity is very close between the two 60-watt equivalent energy saving lights.  But I found it easier to replace the harp with the LED bulb due to its more conventional shape.

LED light dispersal

By stopping down the camera lens, I was able to get a better idea of the light dispersal characteristics of the Cree LED.  As you can see, there's considerably less output from the top (and bottom), making it a less-suitable candidate for spot or downlight applications.  It's ideal for table lamps, where most of the light should come out of the side of the bulb.  

Light dispersal of Cree LED
Note band of light in center, dropoff at top and bottom

Dimmability

I tested the Cree LED against the GE dimmable CFL in a wall sconce controlled by a Lutron wall dimmer switch.  The CFL dimmed about 40% before going completely dark when the dimmer slider was at about the 30% mark.  The LED kept getting dimmer throughout the range of the dimmer slider.  In addition, with the dimmer at its lowest level, I was able to turn off the LED and then turn it back on, while the CFL stayed dark when the switch was toggled.

Summary

I've only had the LED for a couple of hours now - not really enough to make a good comparison, but the combination of energy efficiency, dimmability, relatively low cost and lack of hazardous materials make the Cree seem like a winner.  I'll probably pick up a six-pack on my next run to Home Depot.

One More Thing...

I have nothing to do with any company mentioned other than as an interested consumer.  And in that vein, there's another technology on the horizon that may also prove a lighting game-changer.  It's called ESL (Electron-Stimulated LuminescenceTM) and the company closest to commercialization is VU1 with their 65-watt floodlight replacement.  They hope to have product in the marketplace later this year.  I have an application, so I'll likely pick up one as soon as I can.  If you know of other good lighting products, feel free to leave a comment!

It's almost Christmas: LED vs traditional C9 lights

I've always been traditional with my outdoor Christmas lighting - only the good ol' C9 incandescent light strings are good enough to put on my house.  I've had a number of 25-bulb strings for about 25 years, but since adding solar to our roof in 2010, I've been aware of just how much electricity my holiday lighting is using.  The miniature lights are much better than C9s on a one-for-one basis, but most mini-light strings put their bulbs much closer together than the 12" spacing of my C9 strings, so they're probably somewhat better, but maybe not so much - not enough for me to switch.

The other thing that's always frustrated me about C9 lights are their fragility.  It seems like no matter how gently I put up and take down the strings, every year I have to go through the ritual of finding and replacing the burned out bulbs before stringing them on the house.  And invariably, the one bulb at the apex of the roof burns out 2 nights after I put it up.  And with bulbs going for at least 25¢ apiece, I figure I spend at least $2-$3 a year in bulbs.  There's gotta be a better solution...

Philips C9 faceted Christmas lights

Enter the LED C9 strings.  I bought 4 25-bulb strings of Philips multicolor LED faceted C9 light strings  at the local Target to compare to my incandescent C9 strings.  Although I had a slight preference for the smooth bulbs, I didn't care for the light dispersal as much - the faceted ones seemed to illuminate the entire "bulb" better.

First test:  Energy efficiency

C9 incandescents - about 160 watts

Using my trusty Kill-A-Watt energy meter, I plugged in an incandescent C9 string.  Just about 160 watts (I had a few flashers in the string, so the wattage varied about 10 watts or so as bulbs flashed on & off).  C9s are rated at 7 watts apiece, so a full 25-light string of standard bulbs should be about 175 watts.

C9 LEDs - just 2(!) watts

Next up was an LED strand.  I plugged it in and looked: 2 watts!  The entire string was using less than one-third of the electricity that one C9 bulb consumed!

Second test:  Aesthetics (how they look)

I know what you're thinking - these things must be ridiculously dim.  Truth be told, they are significantly dimmer than C9 incandescents.  But the only way to truly judge is on the house, in the dark, side-by-side - so that's exactly what I did.  The photo below shows a string of incandescent C9s on the main house (starting to the left of the garage door) and a string of LED C9s on the right (over the garage door).  The difference is obvious - you could probably read a book by the incandescents, while the LEDs serve to add just a hint of color to the roofline.

Incandescent C9s on the left, LED C9s on the right
(click for an enlarged image)

As much of a traditionalist as I am, I was surprised to find that I actually prefer the LED lights.  They don't light up the walls of the house, so they don't get washed out by their own brightness.  Couple that with the energy efficiency and lack of annual maintenance, and we have a winner, at least in my book.

Third test: economics (are they worth it?)

So - aesthetics aside, is it worth it economically to use LED C9s instead of incandescents?

If you're buying new, I think that LEDs are a no-brainer unless you really have an issue with their brightness.  They cost about double upfront ($12 vs $6 per 25-light string), but factor in the need to replace bulbs and the electricity difference and the payback is probably 1-3 years.

In my case, I was trying to determine the payback period considering that I already had the incandescent strings.  Here's my thought process and calculations - you'll have to do the math for your scenario and see what works.

I have 4 strings of incandescents.  4 strings of LEDs runs $48.00 + tax - lets round to $50 (I bought mine on sale for $11 each).  I typically have my lights on between Thanksgiving and Christmas, about 4 hours each night.  My wintertime electricity rate is about 12¢ per kWh, so let's run the numbers:

Cost per year for incandescents:

• Replacement bulbs:  $2.00
• Electricity: 160 watts / string x 4 strings x 4 hours / night x 30 nights / year = 76,800 watts (or 76.8 kWh) x 12¢ / kWh = $9.21

So I'm paying about $11.21 per year for my current display.

Cost per year for LEDs:

• Replacement bulbs: $0.00 (each sting included 2 replacement LEDs, but I can't imagine them going bad more than 1-2 per decade - time will tell).
• Electricity: 2 watts / string x 4 strings x 4 hours / night x 30 nights / year = 960 watts (or 0.96 kWh) x 12¢ / kWh = $0.11

So I'll be paying 11¢ per year for the LEDs.

And the Winner is: LEDs

Factor in the upfront cost of $50.00 for the LED strings and you'll see that the breakeven point is between 4 and 5 years for my scenario.  Yours might be different, but I think that in most cases, there's still an excellent case to be made for LED outdoor Christmas lights.

Merry Christmas to you and yours!

Update 11/23/12:  X-10 modules and LED lights don't mix (well)

X-10 modules

I use the old BSR X-10 appliance modules to turn my outdoor (and indoor) Christmas lights on & off remotely - I've done it for years.  The switch to LED lighting brought out a problem - the X-10 modules "leak" a tiny bit of electricity when switched "off".  Appliances and incandescent lighting are unaffected by this, but it's enough to cause LED lights to not turn off completely.

Using the oracle of Google, one can find a number of solutions to this issue - most involving putting a small load on the switched side of the X10 module with the LED lighting - something like an incandescent night light, a plug-in air freshener or even a "wall wart" transformer.  There are also mentions of more sophisticated solutions involving opening up the X10 module and adding or removing resistors.

I opted for the low-tech approach of plugging in a wall wart on the switched side of my X10 modules.  Even without being plugged into anything the wall wart transformer draws enough energy to keep the LED string dark.  It's kludgy, but it works. 

Make a smartphone tripod mount for less than $10.00

Smartphones today have amazing capabilities, both as handheld computers and as digital still and video devices.  However, one thing that's difficult to do is to hold a smartphone steady when taking pictures.  A tripod helps immensely, but it's difficult to find a cellphone (or a cellphone case) that has a tripod socket.

A tripod is also very useful for taking panoramas or time lapses (or even combining the two!).

This is my DIY solution.  I think it has a number of advantages over other DIY designs, including:

• Inexpensive - it can be made for less than $10.00, even if you have to buy everything - but you shouldn't need to.
• Compact & portable - disassembles into  a very small space (about 4"x1"x1") and is lightweight (this is important if you're backpacking to your photo-op!)
• Panorama-capable - can be made to position the lens directly over the tripod pivot - necessary for panorama photography
• Adjustable - will work with most feature-phones and smartphones.

Parts list:

• 3 3"x5/8" mending brace ($2.97 for a pack of 4)Note:  Measure the width of your cellphone and make sure that the length of the brace is at least 1/2" longer.  For larger phones, you may need to use a 4" or even 5" brace.
• 1 3/4"x1/2" corner brace ($1.97 for a pack of 4)
• 3 1/4-20 x 1/2" round head bolt & 4 1/4-20 nut ($1.18 for a pack of 5 bolts & 5 nuts)
• Electrical tape or heat-shrink tubing ($0.71)
• 1 or 2 Large rubber bands

Assembly:

Wrap one corner brace with electrical tape, covering all but about 1/2" of one end.

Take the corner brace and attach it to the taped mending brace with a bolt and nut.  Make sure that the bolt head is on the inside of the brace.

Take one 1/4-20 nut and use it to attach the mount to your tripod's mounting screw.

Optional:  Panorama mount

If you plan to use your phone to take panorama shots, you'll need to ensure that your camera's lens is directly above the tripod's screw (on the axis of rotation of the tripod mount). For this we need to add a couple of extra parts.

Panorama mount assembly:

In place of step 3 above, take a second mending brace and attach it to the other side of the corner brace, again ensuring that the bolt head is on the inside of the corner.

Take a third corner brace and attach it to the second one.  Use the third hole (counting from the corner brace side) on the second mending brace and the end hole on the third brace.

Take one 1/4-20 nut and use it to attach the third corner brace to the tripod head, using the hole on the opposite end of the brace.

Mounting your phone:

Put the rubber band over the upright, taped corner brace.  Place the back of your phone against the back side of the brace and draw the band around the screen and looping it over the top of the taped corner brace.  It should be a tight fit.  If it's not, get a smaller rubber band (or loop the band over the bottom of the brace a few times to take up some  of the slack).

The photo above shows the completed simple mount on an Ikea Stam timer for doing timelapse panoramas.  See this page to build one for yourself.

If you're using the panorama mount, you'll need to adjust the angle between brace #2 & #3 (and possibly the angle of the corner brace relative to brace #2) to get the lens directly over the tripod screw.  Make sure you re-tighten the screws once the alignment is correct.

From the front, you can see how the phone's camera lens is positioned directly over the tripod's screw.  This yields the best panoramas.

Collapsed and ready for transport (LG Optimus S shown for size comparison)

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Update 10/01/12:

Here's an even simpler, lighter design.  It's not as adjustable as the one above, but it should get you "close enough" for panorama shots.

 Basically, you just eliminate the 3rd mending brace in the design above
and rotate the angle bracket by 90°, then use the third hole out to mount
it to the tripod.  Rotate the angle bracket a bit more or less to center
the lens over the pivot point of your tripod.

The photo above shows the completed simple mount on an Ikea Ordning timer for doing timelapse panoramas.  See this page for inspiration.  To build it:

1. Epoxy a 1/4-20 x 1/2" bolt onto center of the top of the timer.
2. Epoxy a 1/4-20 nut to the center bottom of the bottom of the timer.
3. Glue a piece of foam, rubber or other cushioning material onto the bottom of the timer.  It should be about 1/8" thicker than the height of the nut, so that if you mount the timer on a flat surface, the nut doesn't hit.
4. Screw a 1/4-20 nut onto the top bolt, then put on the mount and finally a 1/4-20 bolt (or wing nut, as shown above) and tighten until the unit is secure.

If your camera is heavy and you want to use a modified timer like the Ordning for timelapse panoramas, you might need to use a counterweight to level the top of the timer.  You can use a third mending brace attached to the timer bolt, sticking out in the opposite direction.  Attach a bolt with a nut or two on it as a counterweight (or tape coins, lead weights, etc.).