Driving in the Mountains

We're spending the weekend at our trailer in Buena Vista. It was too windy yesterday to ride our bikes that we brought up, so we decided to drive down Highway 50 over Monarch Pass down to Gunnison. This weekend has been my first chance to drive my new VW Jetta SportWagen TDI in the mountains, so I was interested to see how it handled the higher altitude and steeper grades. The 2.0L TDI makes plenty of power to ascend even a 7% grade at 11,000 feet.

What I was even more impressed with, though, was how well the DSG transmission worked on the descent. I'd already noticed that when braking, the DSG will downshift to help slow down using engine braking. What I had not thought about was how nicely that would work when descending a 7% grade. When coming down from the pass, holding the brake for a moment would cause the DSG to downshift one or two gears. It would hold that gear until I touched the throttle again. It worked perfectly to control the speed coming down a steep grade. I know that I can use the Tiptronic mode to do this manually, and that it will even automatically match the engine speed, but I was impressed that in automatic mode it did this so well on its own.

My previous vehicle, a GMC Sierra K-2500 truck with the Duramax Diesel and Allison transmission would do downhill engine braking, but I think only when it was in Tow/Haul mode. It also worked quite well to control the speed, especially when we were pulling the trailer.

I was also quite pleased to see that for the trip to and from Gunnison, including going over Monarch Pass twice, we still averaged 36 MPG!

VW Jetta SportWagen TDI

Last week I bought my new 2011 Jetta SportWagen TDI, the day before we took a 3,200 mile trip from Denver through Missouri to North Dakota, and back again. The TDI was the perfect car for the road trip, roomy and comfortable, and up to 43MPG on the highway. Based on fill-ups, my best mileage was 39.67MPG, with 486 miles on one fill-up and still a 1/4 tank left. My overall mileage has been about 37MPG, combined city/highway for the first 3,500 miles.

There are quite a few things that I really like about the new Jetta:

• The fuel economy is fantastic. Even in the first 3,500 miles, I'm getting at least 30 MPG driving to and from work, and over 43 MPG on the highway, if I keep the speed down a little...


• The TDI makes plenty of power, especially for an engine that gets such great fuel economy. Although its only 140 HP, the diesel makes 236 ft-lbs. of torque, which is really more important. Plenty of power to accelerate onto the highway, or for passing. I'm anxious to get up into the mountains to see how it does at higher altitude.


• Even though the fuel tank holds only 14.5 gallons, with the great fuel economy that's enough fuel for a range of about 500 miles on the highway, so you don't have to stop to fill up so often.


• After much internal debate, I finally decided on the DSG automatic rather than the manual transmission. While my previous Jetta has a manual transmission, and I can certainly enjoy driving a stick-shift, I thought that for the long term the automatic might be more comfortable. Since the DSG doesn't use a conventional fluid torque converter, its more efficient than traditional automatics, and in fact is often rated with higher fuel economy than the manual. I also thought that since the diesel has a lower redline and narrower (and lower RPM) power band than a gasoline engine, that with the manual you would need to be shifting constantly to stay in the appropriate gear. I decided that it would be better to let the transmission do that for me! Driving the DSG still feels a little quirky at times, although its generally very smooth and shifts very quickly. At startup it feels a little slow to engage sometimes, which can lead you to open the throttle a bit more. Once the transmission and turbo get engaged, it makes for quite a quick start, often quicker than intended. It can actually be challenging to drive this car slowly! ;-) With a bit more practice and patience, though, I'm getting the hang of making smooth starts. The other thing that is taking some adjustment is that the DSG downshifts for you when braking to help you slow down. It seems like the harder you brake, the quicker it downshifts, so braking smoothly can be challenging if you're not paying enough attention. Again with some more practice I'm sure that I'll have the proper finesse soon!


• For a compact car, there is plenty of space inside. The Jetta seems almost as spacious as our Passat, and was very comfortable to ride in even for a long trip. The seats are very comfortable, and easily adjustable to keep comfy even on a long drive. The electric heat was handy to have, as it was only 27 degrees in North Dakota on the morning when we left.


• The car came standard with Bluetooth integration for my cellphone. While this isn't something that I may have ordered if it were an option, I'm really liking the way that it works. Once paired with my phone, it automatically links every time I start the car. If I get a phone call while I'm driving, I can press the phone button on the steering wheel with my thumb, and it mutes the stereo, answers the call, plays it through the speakers, and has a microphone built into the overhead console. It really works quite well.


• I love the soft leather-wrapped 3-spoke steering wheel, with built-in controls for the stereo, phone, and trip computer. I tend to hold onto the lower portion of the steering wheel when driving on the highway, and many 4-spoke wheels like the one in our Passat don't have enough spacing between the top and bottom spokes to fit my hands into comfortably. The 3-spoke wheel works perfectly.


• The car I picked out has the panoramic sunroof and 17" wheel package. I love having the sunroof for ventilation, and it makes the car feel much more open and roomier, even in the back seat, since the glass comes back over the rear seats as well.


• The TDI comes with the Multi-Function Display trip computer, which shows the instantaneous and average fuel consumption, both for the current trip and cumulatively. The trip counters reset after two hours, so it always shows your current activity. It also tracks duration, distance, and average speed for both the current trip and cumulatively. The MFD will also show the phone status, and the current selection on the radio. A new addition, compared with our 2008 Passat, is a simple, large digital speed display. Very nice...


• The touchscreen AM/FM/Satellite Radio/6-CD Changer is also great. Again, although satellite radio is not something that I would have ordered, we did enjoy it on the trip. It was nice to be able to pick a channel by category, and not have to constantly hunt for local radio stations while traveling. I am having the factory Media Device Interface for the iPod installed by the dealer this week, so in the future I'll be able to control my iPod through the radio as well.

So what's missing? I think that about the only thing that would make this car better, perhaps perfect, would be if it were offered with all-wheel drive. Volkswagen has their 4-Motion all-wheel drive systems, like the Audi Quattro, which is only offered on a few of the high-end trim levels of the Passat and CC. There are European versions of the Jetta/Golf that are offered with both TDI and 4-Motion, but not in the US. Even the Audi A3, which is offered with the TDI, or with Quattro, isn't available with both TDI and Quattro. I would most likely have gone with the more expensive A3 if Quattro would have been offered.

I've heard that with the recent tragedy in Japan, that production of many Japanese auto brands may be severely limited for the near future. While Subaru has a US-based factory in West Lafayette, IN, it has closed a number of its plants in northern Japan, the area that sustained the worst damage from the earthquake/tsunami. I think that if VW were to offer a 4-Motion-equiped version of the Jetta SportWagen in the US that it would likely pick up a fair share of Subaru's market. I would guess that many Subaru buyers make their selection because of the all-wheel drive.

State High School Marching Band Competition

Yesterday we went to the Colorado Bandmaster's Association State 4A/5A High School Marching Band Finals held at Falcon Stadium at the Air Force Academy near Colorado Springs.

First I have to say how amazing each and every band performed! I'm very impressed by the level of performance shown by all of these kids. I think that are far above where I remember my high school band, and possibly college bands at the time as well.

I was planning to take pictures of Arapahoe's band and color guard during the semi-finals, since it was during the afternoon when there would be plenty of natural light. We got a phone call from one of the color guard parents asking for help moving the large props that are used during the performance, as not all of the volunteers that they had arranged for had been able to make it. We were happy to help out, but it was a lot of work to wheel them down the hill from the parking lot, and into the tunnel leading to the field. It turned out that the tunnel wasn't quite as tall as they expected, and the candy cane tubes were slightly taller than they thought, so they were a few inches too tall! We tipped a couple of the at an angle to get them through, but decided that was taking too much time. We discovered that removing one of the tie-down straps that attaches the tube to the base allowed the top tube to drop down just enough to clear the top of the tunnel. A quick re-adjustment on the other end of the tunnel, and everything worked out just fine.

Unfortunately, that meant that our vantage point for their afternoon performance was from behind the end zone, instead of high up in the stands, and without my camera...

Arapahoe placed fifth in the semi-finals, so they moved on to the finals in the evening. We were told that there should be plenty of volunteers for the evening, so that we could return to the stands to watch. Even though the 4A finals were first, we wanted to watch, since we've seen some of the 4A bands at some of the other competitions.

During the Loveland High School Band performance, the woman sitting directly behind me was constantly "cat-calling" and "hooting and hollering" so loudly that I couldn't hear the band at all! I tried moving over into the empty seat next to me so that i wasn't directly in front of her, but it didn't really help... At the end of their performance, as the women was gathering her things, she hit me in the head with her bag! She muttered "sorry" and I turned around to tell her "that wasn't as bad as all of the screaming..." She then told me that "if I didn't want any noise, that I shouldn't have come." I told her that I came to hear the bands, not the parents... She then had the gall to tell me that I "should have sat somewhere else..." as if I had some choice about sitting in front of her... What a b****... I guess there isn't much "love" in Loveland... ;-) This is as bad as Little League, where the parents behave worse than the kids, and are more competitive. You know, I think that if she had said "sorry" that she "just got excited when her kids were performing" I probably would have gotten so irritated... But when she turned it back to become MY fault, it really made me angry!

Loveland ended up in second place, behind Air Academy High School, who are very impressive with their speed and precision in their formations. Loveland's show incorporates spreading several enormous tarps on the field in the shape of a crescent moon, one of the elements of their show. It takes an inordinate amount of time to lay out all of the pieces, which have to be taped together in places to hold them down. Last night, two of the kids fell on them. A trombone player seemed to have tripped over one of the edges, and one of the color guard girls seemed to have lost her footing on the slippery surface. I hope that both of the kids are OK...

Arapahoe had perhaps their best performance of the season in the finals. Since they are a smaller band than most of the other 5A bands, they don't seem to project as well as the other bands. They have a great show, though, and did very well. The color guard did a great job, with only a couple of little slips. Overall, the judges marked them 0.4 points lower than Douglas County, so they finished in fifth place in the finals as well. They were rated fifth in the state going into the competition, so really they did as well as expected. See all of the scores here.

Being somewhat new to this, I have a few observations about band competitions in general.

One of the things I find interesting is that the bands are lead by student drum majors, not by the band directors... They do an awesome job of directing, and have amusing salute routines when they start and finish, and during the award presentations. However, I guess that I object somewhat to them being spotlighted so much more than the rest of the band members. Most of them are in different uniforms than the band, which seems unnecessary to me... We can tell that they are the drum majors when they climb onto the stand. Also, some of the bands have their drum majors, who are predominately girls, dressed in evening gowns. While elegant, it doesn't seem to fit in with a "marching band."

Another thing that surprises me is that all of the bands have a "percussion pit" that seems more suited to a concert band than a marching band. Lots of bells, marimbas, and xylophones, chimes, timpani, gongs, etc. Some of it seems like gratuitous use of as many percussion pieces as possible, whether warranted or not. Some of the bands also have electric bass and guitars, and synthesizer keyboards, which are hardly classic marching band instruments. I also notice that none of the bands use handheld cymbals in the drum line, only in the percussion pit. The exhibition performance while the judges tabulated the results was by the University of Northern Colorado band, who didn't use any percussion pit, and had four cymbals in the drum line that worked very nicely.

I also think that some of the elaborate scenery pieces, particularly the tarps spread on the field, like Loveland uses, are both unnecessary and dangerous. Having to step on and off of different surfaces while marching backwards seems like too big of a risk to make it worthwhile. Douglas County High School uses tarps, too, but much smaller than Loveland, and only in one corner of the field. I think that they start out on the tarps, but I don't think that they return to them during the performance.

Again, though, I was very impressed with all of the bands, and congratulate everyone who participated, as a performer, parent or staff. Its obvious that everyone puts a tremendous amount of effort, and lots of practice time, and it all showed on Saturday.

Car Computer vs. Droid

I've been meaning to post something about this for some time, but haven't had a chance...

Last year, I was making some plans to install a computer in my car, to use for navigation, entertainment, etc.

However, in February, I upgraded my cell phone to an Android phone, a Motorola Droid from Verizon.

What I've realized is that everything that I wanted to do with the car computer, Droid does!

I was planning to take my old G4 Mac Mini, and mount it in the trunk. I found a power supply from Carnetix that works with the Mini, and will wake or sleep the computer with the ignition. I found a head unit from Xenarc that is a standard DIN unit that would fit in the dash of my Jetta. The Xenarc has a DVI input to connect for the video on the Mini. It uses a touch screen, which connects to the computer as a USB mouse. It has the amplifier and radio tuner, a volume control, balance and fader, tone controls, etc. so that it works as the head unit even without using the computer.

I have an old Garmin GPS-III, with a serial cable and USB adaptor to use for navigation, using RouteBuddy as the software.

Since the Mac Mini can play DVD's, and has iTunes for music, it would be easy to use for in-dash entertainment. I was thinking that Front Row would make a decent interface to use in the car. I found a plug-in framework called FrontPython that allows adding other applications to Front Row. I was going to build a FrontPython plug-in to add RouteBuddy to Front Row to make it easy to access.

When I got my Droid, I also got the car dock, which is a suction-cup mount that the Droid clips into while driving. The phone works well enough using the speakerphone that I use it for hands-free operation. The Google Maps navigation works great, especially with the voice search. I have used DoubleTwist to sync my iTunes library to the Droid, so I have music available if I wanted. Since the Droid uses a standard 3.5mm headphone jack, I could plug the Droid into auxiliary input on my existing car stereo. I can also stream video from a variety of sources, so I can get plenty of entertainment from the Droid, including email, web, testing, twitter, etc.

Part of my reason for wanting the car computer was to keep me occupied on the frequent occasions that I was sitting in the car waiting for kids. With the Dorid, I have plenty of entertainment, and navigation, in my pocket at all times.

A Lightweight Approach to Wireless Access Point Geolocation

By Brad Tombaugh 17 July 2010
Brad@Tombaugh.org
www.Tombaugh.org
Brad@FullCircleTechSolutions.com
www.FullCircleTechSolutions.com
BTombaugh@gmail.com
Tombaugh.BlogSpot.com

Draft 1.0

Introduction:

One of the side-effects of "wardriving" to detect the locations of wireless access point (WAP) using a mobile device such as a laptop computer with a GPS is that all of the locations of the WiFi hotspots all appear on a map at the location where they were detected, not where the source of the radio signal originates. This generally means that all of the mapped locations of detected networks are marked in the middle of a street.

Theorum:

The geographic location of a wireless access point (WAP) can be approximated by recording the GPS coordinates and signal strength in three or more locations. The point of origin can then be calculated using trilateration.

To optimize efficiency for use with a mobile device such as a smartphone, use of a simple algorythm to capture four points, corresponding to the minimum and maximum latitude and longitude coordinates where the signal from the WAP can be conveniently measured.

Assumptions:

The maximum signal range of a typical commercially produced, consumer-grade wireless access point is roughly 300 ft or 100m.

Since most commercial wireless equipment is provided with an omni-directional antenna, its assumed that the radio signal radiation pattern can be expected to be roughly circular.

While buildings and terrian can reduce the range of wireless signals, in a typical residential area the interference could be assumed to be roughly equal in all directions. Thus, it can be safely ignored when estimating the location of the access point.

The radiated power of the wireless radio signal decays using the inverse square law, decreasing exponentially with distance. The further from the source of the signal, the lower the power reading.

The radiated power of a typical wireless access point can be expected to be in range of a maximum of -10dBm to a minimum usable signal strength of -95dBm.

Due to a maximum distance of less than 500 feet, simple Cartesian coordinates could be used, rather than great circles or Vincenty's Formula.

The observed wireless access points are assumed to be stationery, remaining in a fixed position. I.e. not another mobile device, but a wireless access point/base station.

Approach:

To estimate the actual geographic location coordinates of a wireless access point in a residential or commercial building, readings are typically taken with a laptop computer or wi-fi equipped smartphone. A built-in or externally connected GPS is used to record the coordinates where a signal reading is taken. In practice, readings are generally taken while driving in a moving vehicle on a public street, or perhaps walking with a smartphone. Typical practice for "wardriving" applications such as KisMac are to record the GPS location at the first point where a reading of a particular wireless access point is acquired. The Basic Service Set Identifier (BSSID) and MAC address are recorded for identification. The deficency of this practice is that all of the recorded wireless access points appear to be on streets when the coordinates are mapped, and do not reflect the true origin of the wireless access point.

Commercial applications like SkyHook Wireless record a large number of readings from many points, and use a server-based application to aggregate the results. This approach is impractical for a single laptop or mobile device.

Rather than collecting a large number of points, only three points are needed to trilaterate the location. The question is how to determine which of many possible points should be recorded. My approach is a simple process to record coordinates and signal strength at the four "corner points" with the minimum and maximum values for latitude and longitude. This can be determined using a simple calculation to see if the observed point is greater than the previously recorded maximum for either latitude or longitude, or if the point is less than the previously recorded minimum values.

Once four points have been collected, the approximate location of the origin can be calculated by determining the intersection of four circles representing the recorded coordinates as the origins of each circle, having a radius relative to signal strength reading.

Since Android smartphones report the signal strength in dBm, ranging in value from -10dBm maximum signal strength, to a minimum detectable signal strength of -100dBm, it is easy to approximate the distance from the source by using the absolute value of the signal strength as the distance in meters. This correlates to an approximate distance of 30ft or 10m where the signal strength is the strongest, to approximately 300ft or 100m where the signal strength is the weakest.

Calculation:

Calculation of the intersection of four circles is based on this article at Mathworks:

yes, four circles n radii is known..... all are different radii also...... can u tell me the algorithm for it...... i must find center for the intersection area also.......... i hav an image to show the intersection area made by four circle but i don know how to post it..... recommend any site to post pic for view......

Ok, if the radii are known, then just do this. We know the equations of each circle.

(x - x1)^2 + (y-y1)^2 = R1^2
(x - x2)^2 + (y-y2)^2 = R2^2
(x - x3)^2 + (y-y3)^2 = R3^2
(x - x4)^2 + (y-y4)^2 = R4^2

Subtract one from the rest. Thus

2*(x2 - x1)*x + 2*(y2 - y1)*y = R2^2 - R1^2 + x1^2 - x2^2
2*(x3 - x1)*x + 2*(y3 - y1)*y = R3^2 - R1^2 + x1^2 - x3^2
2*(x4 - x1)*x + 2*(y4 - y1)*y = R4^2 - R1^2 + x1^2 - x4^2

This is a linear system of 3 equations in the two unknowns (x,y). Solve using backslash (\ operator in Matlab).

A = 2*[(x2 - x1),(y2 - y1);(x3 - x1),(y3 - y1);(x4 - x1),(y4 - y1)];
rhs = [R2^2 - R1^2 + x1^2 - x2^2 + y1^2 - y2^2; ...
R3^2 - R1^2 + x1^2 - x3^2 + y1^2 - y3^2; ...
R4^2 - R1^2 + x1^2 - x4^2 + y1^2 - y4^2];

xy = A\rhs

This will derive an estimate of the center coordinates.

See an illustration.

Alternate Calculation:

Since the calculation of the intersection of four circles is rather complex to perform on a mobile device, we can approximate the position by determining the bounding rectangle where the four minimum and maximum latitude and longitude points where the wireless signal was detected. This may not work in all cases, but can serve as an illustration of the approach. In particular, this approach would not yeild good results for cases where there are not detection points from at least three sides. The origin of the signal would have to be contained within the area defined by the detection points.

We can further refine the bounding rectangle which should contain the origin of the signal source by determining the boundries implied by the relative signal strengths measured at each of the points. For example, if the signal strength measured at the northern-most point was -90dBm, we would assume that the source of the signal must be within approximately 90m south of the coordiantes recorded. By calculating the coordinates with maximum distances from the points of detection, based on the signal strengths measured at each point, we can determine a small area bounded by these points. There should be a high probability that the source of the wireless signal originates from within this bounding rectangle. Taking the geometric centroid of this bounding rectangle should approximate the origin of the wireless signal.

This can be illustrated by the interactive map linked here. The white circle drawn in the center of the map represents the actual location of the wireless access point, or the origin. The blue circle represents the approximate range from the northern-most point of detection, based on the signal strength. The yellow circle represents the eastern-most point of detection, the red circle for the southern-most, and the orange circle representing the western-most point of detection.

From this set of coordinates, we can draw a bounding rectangle shown in purple, which represents the range of coordinates where the wireless signal could be detected. Based on the layout of streets and accessability of the area, the actual origin of the signal could be contained with this bounding rectange if the points of detection were accessible from at least three sides, or possibly all four sides. However, in cases where the wireless signal can only be observed from one side, such as a facing street, the bounding rectangle defined by the points of observation would not encompass the origin, but would be adjacent to it.

Because we cannot be certain that the set of detection points actually enclose the point of origin, and to determine the smallest possible area with the highest probability of containing the point of origin, we calculate a bounding rectangle by determining a set of points which are the furthest possible distance from the minimum and maximum geographic coordinates based on the measured signal strength.

The bounding rectangle shown in green on the map below represents the most likely boundries in which the signal originates, by calculating the distances infered from the measured signal strength at the extreme coordinates where the wireless access point could be detected.

Implementation Approach:

The Android smartphone environment is well suited to this approach, since it combines a wireless network transceiver, with signal strength reported in dBm, with a GPS receiver with good precision, along with enough computing power and data storage to record the detected coordinates. The Android-Wardrive application by Raffaele Ragni is particularly well-suited to this approach because it already records its data in a Sqlite3 database. It also shows a map of the detected wireless access points using the Google Maps API, and can export to an online database or a Google Earth KML file.

The first step to implementing this approach would be to extend the Sqlite3 database schema to include four additional coordinate pairs as well as their signal strength. The existing coordinates could be retained to map the initial point of detection, and could be updated by the geolocation calculation.

Due to the computing overhead involved in performing the calculations, it would not be recommended to attempt to calculate the geolocation in real time. There will be significant amount of additional overhead in collecting the additional data points, especially in an area with multiple wireless access points. Additionally, the method for geolocation requires that a reasonable survey be completed to detect the greatest diversity of locations for best results.

During the initial detection of a new wireless access point, in addition to logging the current geographic coordinates and BSSID, the initial coordinates and signal strength should be written to each of the peripheral coordinate pairs.

With each subsequent reading, the current location point would be compared with the four peripheral coordinate points. If the new reading is further North (current latitude > stored Northern latitude) then the new coordinates (both latitude and longitude of the current location) along with the signal strength should be written as the Northern-most coordiantes. If the new location is further South (current latitude < stored Southern Latitude) than the current location coordinates (both latitude and longitude) and the signal strength should be stored as the new Southern-most point of detection. Similar comparisons should be made for each of the extreme East and West points of detection using the maximum and minimum longitude. It is both possible and likely that during the initial data collection, each new point detected could replace two of the previously recorded coordinate pairs.

The geolocation calculation could either be added as an addition option under the menu, or could be combined with the Export to KML option.

Getting ready to watch Madisen Beaty (@madisenofficial) in "The Pregnancy Pact" on Lifetime

Volkswagen CC

We had a few minutes to kill at the VW dealer this morning, while waiting to pick up Jeannette's Passat after an oil change. We wandered into the showroom, and checked out the new CC. Its similar in many ways to the Passat, but in a very sleek package! The exterior styling of the CC has a profile similar to a Mercedes CLS, scaled down a little... The price is scaled down a little, too!

The two-tone interior is awesome. Its available with the 2.0 liter turbo, which I think is a fantastic engine. 200hp, but still over 20mpg city and 30mpg on the highway. We've gotten 37mpg in the Passat driving in the mountains, which is pretty amazing...

In another year, when Melissa starts driving, it might be a tough call for me to decide between replacing the old Jetta with a CC, or a Jetta TDI...

Google Wave

A few days ago, I got an email invitation for Google Wave. In the video of the demo/presentation they made at their developers conference earlier this year, Wave is Google's idea of what email might be like if it were invented today, instead of 40 years ago... I think it looks very interesting! Sort of a combination of email, instant messaging, and an interactive "wiki" editable in real-time by multiple people at once. They showed some neat integration with Wave, Twitter, and Blogger, where the same comments posted in one place appeared in all three automatically, in real-time. I have invites left, let me know if you're interested...

My Life Just Got A Little Cheaper

Had to go to WalMart this morning to pick up refills on my prescriptions. As we walked in the door, Jeannette started pointing at the sign we passed advertising Prevacid - now available Over The Counter! We had to wait awhile for the pharmacy to open, so we started shopping for some groceries and things... We walked past the display for the Prevacid, available as either 14 pills or 42, but only a 15mg dose, where the one I take every day is 30mg. The 42 pack was just over $25, which is about half of what I pay as my co-pay for a 30 day supply. Once the pharmacy opened, I asked them if Prevacid was available as a "generic" yet, and one of pharmacy techs in back said "Yes, we just got it yesterday!" So, it turns out that the generic as a prescription is a better deal -- a 30 day supply of 30mg dose was under $15! Thats much better than $50 every month!