“This kid invented two of the best ten card tricks in the last decade, so you should give him a chance.”

I wish that I’d had that kind of glowing recommendation from Martin Gardner to get into grad school. At Harvard, of all places.

For Persi Diaconis’ Next Magic Trick …

I also learned a new technical term “smooshing”, which seems to be very similar (at least in a general way, in that the cards all stay in the same plane) to “52 pickup”!

Rooftop Network Outage at Mi Casa

In case you’re wondering where my webcams and weather station have gone, it appears that I’ve got a local problem with the power supply to the rooftop from the shack in the house.

Up on the roof is a GigE 8 port switch, two IP cameras, an ancient Linksys WRT54G router to provide Wi-Fi coverage around the property, a Raspberry Pi and SDR USB dongle running as an ADS-B receiver, and a UBNT 5 GHz bullet supplying a link to another Bullet over on the roof of the garage, to get my local network out to stuff in the garage. In addition, in the box on the roof, there’s a 12 vdc to 5 vdc converter to supply power to the Raspberry Pi. All told, this is only about 20-25 w of power consumption, which at the fused voltage of 12 vdc, should only be 2 A or so. So I can’t see the reason that a 10 A fuse is getting taken out.

I supply both 12 vdc and 48 vdc to the roof via a cable from the shack. There’s a 12 vdc to 48 vdc 150 w dc-dc converter in the shack to generate the 48 vdc. Both that and the raw 12 vdc are sourced from the 12 vdc deep-cycle battery in the shack, through a single 10 A fuse.

For some reason, yesterday I discovered the 10 A fuse had blown. Not good. I replaced the fuse and it appeared to start working again. However, I see this morning that the cameras and wx station were last heard from around 0641 local, so I suspect the fuse blew again.

Looks like this afternoon will include a visit to the roof to see what’s up.


A Little Diversion – Bad Religion Concert at the Tempe Marquee Theater

All work and no play is no fun. This week I’ve started new employment at a large engineering services/systems engineering firm, in the very nice Solar One building overlooking Tempe Town Lake. I’m having a blast attempting to get up to speed on so many new (for me) projects, including California High Speed Rail.

So across the street from our building is the Marquee Theater. I’ve never paid much attention to it and never seen it used – I guess I didn’t visit this area ever in the evening. And I find out that my most favorite punk band, Bad Religion, is playing there that evening!

So, after work, I run home to change into more suitable mosh-pit clothes, then return to the office and repark in the same space I’d left 2 hours before. Walk across the street, and suddenly am wading through a crowd of people of all ages, from a little girl, wearing big time hearing protection, being carried by her father, to a couple of teens, one in a full furry chicken suit and the other in a Micky Mouse suit (I have no idea what those were about), to a slew of 20- and 30-somethings, to a bunch of old geezers and geezerettes like me.

Bad Religion has been around since about 1978, and I remember them in the punk rock scene in LA, where I grew up. Never saw them live, though. Greg Graffin, with a PhD in Evolutionary Biology, fronts the band as lead singer and songwriter. He, and most of the members of the band, are in their 50s as well, so I didn’t feel too out of place %^).

sorry about the out-of-focus, but I was having a very hard time holding the camera still…

Besides the fact that they rocked like they hadn’t aged a day, I found it interesting that none of the guitars were connected wirelessly. I don’t know enough about the business to know if wireless is common now or not, but for me, the cord has always been an issue and of course something that gets worn out quickly on stage. His mike was wireless, but there were two wired stand mikes for the bassist and lead guitarist to use for the harmony parts. They all appeared to have wireless monitor earpieces so they could hear themselves play. I think that the radio frequency band used for these wireless gadgets is in the 174 – 216 MHz spectrum, and that they’re analog, but even that I don’t know for sure. Looks like it’s time for me to do a little investigating.

Update on GPS Constellation Monitoring S/W

I’ve been fortunate enough to be able to do a bit of correspondence with 4river, the author of the NMEA Monitor, as well as a bunch of other interesting s/w tools. He updated NMEA Monitor based upon my recommendation to add the ability to display lat/lon in decimal degrees as well as the ddmmss and ddmm.mmmm formats. I don’t think well in sexagesimal, so having dd.dddddd is handy for me. In case you’re interested, decimal degrees are now included as an option in NMEA Monitor V 2.0.

More on the NEV

Very early this morning I was unable to sleep, so I retired to the shack to draw up the battery system for the NEV.

The first figure is the original battery layout. It helps to realize that the batteries are located under the driver’s bench seat. The bench seat hinges in front and tilts up toward the front of the vehicle. Unfortunately, the steering wheel is enough in the way that the seat will not stay in that position, so I need to use a piece of rope or a couple of bungie cords to hold the seat in the open position. The dashed box in the first drawing shows the limited access to the batteries from this opening. In the original design, the rear 3 batteries are partially covered by the back of the front seat and a plastic cowling which is impossible to remove without removing the rear seat assembly, which is an extra pain.

Figure 2 shows the new battery layout. Only significant change is that the rear 3 batteries have been turned around so that the positive terminals are clearly accessible.

Figures 3 through 6 provide a little detail on the old versus new battery configuration, from a dc resistance point of view. The long and short of it is that even though the new configuration makes for longer jumpers, the exclusive use of 2 gauge copper jumper cable actually provides for a lower total resistance, making the battery assembly that much more efficient.

Tonight I’d prefer to sleep as opposed to thinking more about this right now.

Getting the NEV Running Again!

What’s an NEV, inquiring minds ask? Why, it’s a Neighborhood Electric Vehicle!

Yes, it looks a lot like a golf cart, and to the uninspired, it smells and feels like one, but to the IRS and the DMV it’s a potentially street-legal electric-powered vehicle. Importantly, here in Arizona it’s a vehicle covered here under Arizona Title 28 Transportation, which describes the street-licensed vehicle parked in my driveway.

This particular one was a boondoggle purchase way back in 2009, due to some extremely generous federal tax credit legislation passed in 2008. Basically, the vehicle was a serious bargain. Runs off 48 VDC (eight 6-volt US Battery 250HC XC batteries), has a speed governor set to 25 MPH max, will easily run miles and miles on a single charge, has a AZ state license plate and registration, and has seat belts, headlights and turn signals.

In our neighborhood, which is gated with private streets, I can run the thing all day. Speed limit in the neighborhood is 20 MPH, with only 4 stop signs and over 2 miles of paved street. If I want to sneak out of the closed neighborhood, according to the statute (noted above) the vehicle is street-legal on roads with speed limits no greater than 35 MPH, and is permitted to cross streets with higher speed limits.

The NEV had been sitting in the boneyard for a few years and the batteries were in pretty poor condition. I know, I should know better on how to manage heavy expensive batteries, but the way the vehicle was built it is a bit challenging to water the batteries and they seem to, from day one, vent copious amounts of sulfuric acid vapor, causing all sorts of corrosion and erosion. Since each battery weighs about 40 kg, pulling all 8 batteries to properly inspect and water is a royal pain. However, I tore the vehicle apart again last month and determined to make all new cables, clean up all the corrosion, and get the thing running again.

For the most part, it’s all back together again and appears to work fine. I purchased 20′ of 2 gauge Excelene welding cable, 25 2-gauge solid copper tinned terminals, and an 8-ton handy-dandy hydraulic crimper tool with a bunch of dies (in case I want to go all hard-core with some 4/0 cables). This wealth of stuff set me back about $80. Add to this some silicone adhesive/sealant, adhesive-backed heat-shrink tubing, and boom! I’ve got new jumper cables to run from the motor controller to the battery bank.

This time I reorganized the batteries so that all the positive posts are completely accessible any time, so that I can more easily clean off the buildups of copper oxide/sulfide/sulfate residues that collect in mere days. This means that some jumpers are a little longer than in the original setup, but since they were using 4-gauge cable before I can stand the slightly greater lengths without sacrificing much at all. The maintenance headache reduction and reduced back strain to me are worth much more.

So, what do I do with this puppy? Well, not much, actually. When I first got it I did take it for some 5 to 10 mile drives, found my way (accidentally, really, truly) on to some golf course roads, went to the grocery store a few miles away (at night, no less), and even took it through the drive-through at Jack in the Box. Beyond that, none of my once-vaunted dreams to add wireless telemetry, GPS, audio, etc., ever transpired. However, I’m feeling the urge to finally get to these projects.

I am currently looking at using an Arduino as my real-time sensor controller, collecting battery voltage, maybe battery temperature, day/night light level, stuff like that. I might use Wi-Fi to form an RF link back to the house, possible as I put a 2.4 GHz Wi-Fi AP at 15′ atop the house on an 8 dBi omni antenna. In the Tahoe (which has a 5-6 dBi omni), I can actually get to one end of the neighborhood on the Wi-Fi link. However, I’m thinking more about using the 2m ham band and amateur packet radio, just in case I want to wander a bit further. I happen to have a little 5 watt 2m transceiver module, and a spare Kantronics KPC3Plus TNC, and a little GPS brick. The whole thing should pull less than 600 mW (50 mA average at 12 vdc), and transmit telemetry and position packets every minute. And, aprs.fi is already set up to display things like this, so there’s no backend work for me to do.

I’ve just started new employment, so this project, while exciting and interesting, will probably not get started for a while. But, while I’m continuing to procrastinate, I will also consider another project that I never got started on for this little NEV, and that was to add about 300 to 400 W of solar panel to the roof, so that I can trickle-charge the batteries at up to about 8 A (sadly, this is maybe C/35, so that’s why it’s a trickle charger). To add the panels I’ll need to find someone to weld up a sturdy bracket, and but at least in theory I could really be grid-free at least for short distances! And I’d be the talk of the neighborhood!!!

Happy Chemtrail Conspiracy Day!

This morning I went out to get the car serviced. Wow, what a sky! Our quasi-benevolent alien overlords must be really busy today…

Appears that there’s significant upper-atmosphere water content as it makes for an impressive day of long-lingering aircraft contrails.

Some very discrete trails near the sun

I also tried out the new “Panorama” feature on my iPhone, to grab a pair of 180° views.

Centered on NNW
centered on SSE

Not all the clouds visible are from the contrails. With a little effort, it’s possible to separate some of the naturally occurring cirrus from the a/c contrails, but you can see places where the contrails have smeared out enough that telling the difference becomes more challenging.

Ok, gotta stop this post now. I think they’re on to me.