Everywhere I go, a vast majority of people seem to now have two things in associating with their phone -- a protective case, and a spare USB charging battery. The battery is there because most phones stopped having switchable batteries some time ago. The cases are there partly for decoration, but mostly because anybody who has dropped a phone and cracked the screen (or worse, the digitizer) doesn't want to do it again -- and a lot of people have done it.

Back in 2008, I proposed the idea of a scanner club which would share high-end scanning equipment to rid of houses of the glut of paper. It's a harder problem than it sounds. I bought a high-end Fujitsu office scanner (original price $5K, but I paid a lot less) and it's done some things for me, but it's still way too hard to use on general scanning problems.

There has been lots of buzz over announcements from Tesla that they will sell a battery for home electricity storage manufactured in the "gigafactory" they are building to make electric car batteries. It is suggested that 1/3 of the capacity of the factory might go to grid storage batteries.

This is very interesting because, at present, battery grid storage is not generally economical. The problem is the cost of the batteries. While batteries can be as much as 90% efficient, they wear out the more you use and recharge them. Batteries vary a lot in how many cycles they will deliver, and this varies according to how you use the battery (ie. do you drain it all the way, or use only the middle of the range, etc.) If your battery will deliver 1,000 cycles using 60% of its range (from 20% to 80%) and costs $400/kwh, then you will get 600kwh over the lifetime of a kwh unit, or 66 cents per kwh (presuming no residual value.) That's not an economical cost for energy anywhere, except perhaps off-grid. (You also lose a cent or two from losses in the system.) If you can get down to 9 cents/kwh, plus 1 cent for losses, you get parity with the typical grid. However, this is modified by some important caveats:

• If you have a grid with very different prices during the day, you can charge your batteries at the night price and use them during the daytime peak. You might pay 7 cents at night and avoid 21 cent prices in the day, so a battery cost of 14 cents/kwh is break-even.
• You get a backup power system for times when the grid is off. How valuable that is varies on who you are. For many it's worth several hundred dollars. (But not too many as you can get a generator as backup and most people don't.)
• Because battery prices are dropping fast, a battery pack today will lose value quickly, even before it physically degrades. And yes, in spite of what you might imagine in terms of "who cares, as long as it's working," that matters.

The magic number that is not well understood about batteries is the lifetime watt-hours in the battery per dollar. Lots of analysis will tell you things about the instantaneous capacity in kwh, notably important numbers like energy density (in kwh/kg or kwh/litre) and cost (in dollars/kwh) but for grid storage, the energy density is almost entirely unimportant, the cost for single cycle capacity is much less important and the lifetime watt-hours is the one you want to know. For any battery there will be an "optimal" duty cycle which maximizes the lifetime wh. (For example, taking it down to 20% and then back up to 80% is a popular duty cycle.)

The lifetime watt hour number is:

Number of cycles before replacement * watt-hours in optimum cycle

The $/lifetime-wh is:

(Battery cost + interest on cost over lifetime - battery recycle value) / lifetime-wh

(You must also consider these numbers around the system, because in addition to a battery pack, you need chargers, inverters and grid-tie equipment, though they may last longer than a battery pack.)

I find it odd that this very important number is not widely discussed or published. One reason is that it's not as important for electric cars and consumer electronic goods.

Electric car batteries

In electric cars, it's difficult because you have to run the car to match the driver's demands. Some days the driver only goes 10 miles and barely discharges before plugging in. Other days they want to run the car all the way down to almost empty. Because of this each battery will respond differently. Taxis, especially Robotaxis, can do their driving to match an optimum cycle, and this number is important for them.

A lot of factors affect your choice of electric car battery. For a car, you want everything, and in fact must just do trade-offs.

• Cost per kwh of capacity -- this is your range, and electric car buyers care a great deal about that
• Low weight (high energy density) is essential, extra weight decreases performance and range
• Modest size is important, you don't want to fill your cargo space with batteries
• Ability to use the full capacity from time to time without damaging the battery's life much is important, or you don't really have the range you paid for and you carry its weight for nothing.
• High discharge is important for acceleration
• Fast charge is important as DC fast-charging stations arise. It must be easy to make the cells take charge and not burst.
• Ability to work in all temperatures is a must. Many batteries lose a lot of capacity in the cold.
• Safety if hit by a truck is a factor, or even safety just sitting there.
• Long lifetime, and lifetime-wh affect when you must replace the battery or junk the car

Weight is really important in the electric car because as you add weight, you reduce the efficiency and performance of the car. Double the battery and you don't double the range because you added that weight, and you also make the car slower. After a while, it becomes much less useful to add range, and the heavier your battery is, the sooner that comes.

That's why Tesla makes lithium ion battery based cars. These batteries are light, but more expensive than the heavier batteries. Today they cost around $500/kwh of capacity (all-in) but that cost is forecast to drop, perhaps to $200/kwh by 2020. That initial pack in the Tesla costs $40,000, but they will sell you a replacement for 8 years down the road for just $12,000 because, in part, they plan to pay a lot less in 8 years.

Musings on the economies of cutting the cord.

Over the past 14 years, there has been only one constant in my TV viewing, and that's The Daily Show. I first loved it with Craig Kilborn, and even more under Jon Stewart. I've seen almost all of them, even after going away for a few weeks, because when you drop the interview and commercials, it's a pretty quick play. Jon Stewart's decision to leave got a much stronger reaction from me than any other TV show news, though I think the show will survive.

The government baked robocar projects in the UK are going full steam, with this press release from the UK government to accompany the unveiling of the prototype Lutz pod which should ply the streets of Milton Keynes and Greenwich.

Electric Vehicles are moving up, at least here in California, and it's gotten to the point that EV drivers are finding all the charging stations where they want to go already in use, forcing them to travel well outside their way, or to panic. Sometimes not charging is not an option. Sometimes the car taking the spot is already mostly charged or doesn't need the charge much, but the owner has not come back.

Here in Silicon Valley, there is a problem that the bulk of the EVs have 60 to 80 miles of range -- OK for wandering around the valley, but not quite enough for a trip to San Francisco and back, at least not a comfortable one. And we do like to go to San Francisco. The natives up there don't really need the chargers in a typical day, but the visitors do. In general, unless you are certain you are going to get a charger, you won't want to go in a typical EV. Sure, a Tesla has no problem, but a Tesla has a ridiculous amount of battery in it. You spend $40,000 on the battery pack in the Tesla, but use the second half of its capacity extremely rarely -- it's not cost effective outside the luxury market, at least at today's prices (and also because of the weight.)

Charging stations are somewhat expensive. Even home stations cost from $400 to $800 because they must now include EVSE protocol equipment. This does a digital negotiation between the car and the plug on how much power is available and when to send it. The car must not draw more current than the circuit can handle, and you want the lines to not be live until the connection is solid. For now that's expensive (presumably because of the high current switching gear.) Public charging stations also need a way to doing billing and access control.

Another limit on public charging stations, however, is the size of the electrical service. A typical car wants 30 amps, or up to 50 if you can get it. Put in more than a few of those and you're talking an upgrade to the building's electrical service in many cases.

I propose a public charging pole which has 4 or even 8 cords on it. This pole would be placed at the intersection of 4 parking spots in a parking lot. (That's not very usual, more often they end up placed against a wall, with only 2 parking spots in range, because that's where the power is.) The station, however, may not have enough power to charge all the cables at once.

At CES, there were a couple of "selfie drones." The Nixie is designed to be worn on your wrist, taken off, thrown, and then it returns to you after taking a photo or video. There was also the Zano which is fancier and claims it will follow you around, tracking you as you mountain bike or ski to make a video of you just as you do your cool trick.

In continuation of my series on fixing politics I would like to address the issue of debates. Not just presidential debates, but all levels.

There is great buzz about some sensor-laden vehicles being driven around the USA which have been discovered to be owned by Apple Computer. The vehicles have cameras and LIDARs and GPS antennas and many are wondering is this an Apple Self-Driving Car? See also speculation from cult of Mac.

Bitcoin's been on a long decline over the past year, and today is around $220 per coin. The value has always been based on speculation about Bitcoin's future value, not its present value, so it's been very hard to predict and investment in the coins has been risky.

Some thinking led me to a scary conclusion. Recent news has revealed that a number of "cloud mining" companies have shut down after the price drop. Let me explain why.

After yesterday's story about Uber and CMU, a lot of speculation has flown that Uber will now be at odds with Google, both about building robocars and also on providing network taxi service, since another rumour said Google plans to launch an Uber like "ride share" service.

I commonly see statements from connected car advocates that vehicle to vehicle (V2V) and vehicle to infrastructure communications are an important, even essential technology for robocar development. Readers of this blog will know I disagree strongly, and while I think I2V will be important (done primarily over the existing mobile data network) I suspect that V2V is only barely useful, with minimal value cases that have a hard time justifying its cost.

Of late, though, my forecast for V2V grows even more dismal, because I wonder if robocars will implement V2V with human-driven cars at all, even if it becomes common for ordinary cars to have the technology because of a legal mandate.

The problem is security. A robocar is a very dangerous machine. Compromised, it can cause a lot of damage, even death. As such, security will have a very strong focus in development. You don't want anybody breaking into the computer systems or your car or anybody else's. You really don't want it.

One clear fact that people in security know -- a very large fraction of computer security breaches caused by software faults have come from programs that receive input data from external sources, in particular when you will accept data from anybody. Internet tools are the biggest culprits, and there is a long history of buffer overflows, injection attacks and other trouble that has fallen on tools which will accept a message from just anyone. Servers (which openly accept messages from outside) are at the greatest risk, but even client tools like web browsers run into trouble because they go to vast numbers of different web sites, and it's not hard to trick people to sending them to a random web site.

We work very hard to remove these vulnerabilities, because when you're writing a web tool, you have no choice. You must accept input from random strangers. Holes still get found, and we pay the price.

The simplest strategy to improve your chances is to go deaf. Don't receive inputs from outside at all. You can't do that in most products, but if you can close off a channel without impeding functionality it's a good approach. Generally you will do the following to be more secure:

1. Be a client, which means you make communications requests, you do not receive them.
2. You only connect to places you trust. You avoid allowing yourself to be directed to connect to other things
3. You use digital signature and encryption to assure that you really are talking to your trusted server.

This doesn't protect you perfectly. Your home server can be compromised -- it often will be running in an environment not as locked down as this. In fact, if it becomes your relay for messages from outside, as it must, it has a vector for attack. Still, the extra layer adds some security.

Rumours reported in TechCrunch suggest Uber is opening a robocar lab in Pittsburgh and hiring up to 50 CMU folks to staff it.

Update: On the Uber blog we now see it's more funding of research labs at CMU, on many topics

Uber's gotten a lot of bad press over its surge pricing system. As prices soared during Storm Sandy and a hostage crisis in Sydney, people saw it as price gouging when times are tough.

As some of you may know, I have been working as chair of computing and networking at Singularity University. The most rewarding part of that job is our ten week summer Graduate Studies Program. GSP15 will be our 7th year of it.

Some new results from the NGV Team at the University of Michigan describe different approaches for perception (detecting obstacles on the road) and localizations (figuring out precisely where you are.) Ford helped fund some of the research so they issued press releases about it and got some media stories. Here's a look at what they propose.

Let me confess a secret fear. I suspect that the first "autopilot" functions on cars is going to be a bit boring.

I'm talking the offerings like traffic jam assist from Mercedes, super cruise from Cadillac and others. The faster highway assist versions which combine ADAS functions like lane-keeping and adaptive cruise control to keep the car in its lane and a fixed distance from the car in front of you. What Tesla has promoted and what scrappy startup "Cruise" plans to offer as a retrofit later this year. This is, in NHTSA's flawed "levels" document what could be called supervision type 2.

Some of them also offer lane change, if you approve the safety of the change.

All these products will drive your car, slow or fast on highways, but they require your supervision. They may fail to find the lane in certain circumstances, because the makers are badly painted, or confusing, or just missing, or the light is wrong. When they do they'll kick out and insist you drive. They'll really insist, and you are expected to be behind the wheel, watching and grabbing it quickly -- ideally even noticing the failure before the system does.

Some will kick out quite rarely. Others will do it several times during a typical commute. But the makers will insist you be vigilant, not just to cover their butts legally, but because in many situations you really do need to be vigilant.

Testing shows that operators of these cars get pretty confident, especially if they are not kicking out very often. They do things they are told not to do. Pick up things to read. Do e-mails and texts. This is no surprise -- people are texting even now when the car isn't driving for them at all.

To reduce that, most companies are planning what they call "countermeasures" to make sure you are paying attention to the road. Some of them make you touch the wheel every 8 to 10 seconds. Some will have a camera watching your eyes that sounds an alarm if you look away from the road for too long. If you don't keep alert, and ignore the alarms, the cars will either come to a stop in the middle of the freeway, or perhaps even just steer wild and run off the road. Some vendors are talking about how to get the car to pull off safely to the side of the road.

There is debate about whether all this will work, whether the countermeasures or other techniques will assure safety. But let's leave that aside for a moment, and assume it works, and people stay safe.

I'm now asking the harder question, is this a worthwhile product? I've touted it as a milestone -- a first product put out to customers. That Mercedes offered traffic jam assist in the 2014 S-Class and others followed with that and freeway autopilots is something I tell people in my talks to make it clear this is not just science fiction ideas and cute prototypes. Real, commercial development is underway.

That's all true, and I would like these products. What I fear though, is whether it will be that much more useful or relaxing as adaptive cruise control (ACC.) You probably don't have ACC in your car. Uptake on it is quite low -- as an individual add-on, usually costing $1,000 to $2,000, only 1-2% of car buyers get it. It's much more commonly purchased as part of a "technology package" for more money, and it's not sure what the driving force behind the purchase is.

Highway and traffic jam autopilot is just a "pleasant" feature, as is ACC. It makes driving a bit more relaxing, once you trust it. But it doesn't change the world, not at all.

I admit to not having this in my car yet. I've sat in the driver's seat of Google's car some number of times, but there I've been on duty to watch it carefully. I got special driver training to assure I had the skills to deal with problem situations. It's very interesting, but not relaxing. Some folks who have commuted long term in such cars have reported it to be relaxing.

A Step to greater things?

If highway autopilot is just a luxury feature, and doesn't change the world, is it a stepping stone to something that does? From a standpoint of marketing, and customer and public reaction, it is. From a technical standpoint, I am not so sure.

For many decades, cameras have come with a machine screw socket (1/4"-20) in the bottom to mount them on a tripod. This is slow to use and easy to get loose, so most photographers prefer to use a quick-release plate system. You screw a plate on the camera, and your tripod head has a clamp to hold those plates. The plates are ideally custom made so they grip an edge on the camera to be sure they can't twist.

In my earlier article on robocar challenges I gave very brief coverage to the issue of parking. Challenged on that, I thought it was time to expand.

The world "parking" means many things, and the many classes of parking problems have varying difficulties.

I'm sure, like me, you have lots of electronic gadgets that have status LEDs on them. Some of these just show the thing is on, some blink when it's doing things. Of late, as blue LEDs have gotten cheap, it has been very common to put disturbingly bright blue LEDs on items.