Tesla Model S Battery Pack Teardown

February 28, 2017 by Jenny List 78 Comments

We’ve heard a lot about the Tesla Model S over the last few years, it’s a vehicle with a habit of being newsworthy. And as a fast luxury electric saloon car with a range of over 300 miles per charge depending on the model, its publicity is deserved, and that’s before we’ve even mentioned ~~autonomous driving~~ driver-assist. Even the best of the competing mass-produced electric cars of the moment look inferior beside it.

Tesla famously build their battery packs from standard 18650 lithium-ion cells, but it’s safe to say that the pack in the Model S has little in common with your laptop battery. Fortunately for those of a curious nature, [Jehu Garcia] has posted a video showing the folks at EV West tearing down a Model S pack from a scrap car, so we can follow them through its construction.

The most obvious thing about this pack is its sheer size, this is a large item that takes up most of the space under the car. We’re shown a previous generation Tesla pack for comparison, that is much smaller. Eye-watering performance and range come at a price, and we’re seeing it here in front of us.

The standard of construction appears to be very high indeed, which makes sense as this is not merely a performance part but a safety critical one. Owners of mobile phones beset by fires will testify to this, and the Tesla’s capacity for conflagration or electrical hazard is proportionately larger. The chassis and outer cover are held together by a huge array of bolts and Torx screws, and as they comment, each one is marked as having been tightened to a particular torque setting.

Under the cover is a second cover that is glued down, this needs to be carefully pried off to reveal the modules and their cells. The coolant is drained, and the modules disconnected. This last task is particularly hazardous, as the pack delivers hundreds of volts DC at a very low impedance. Then each of the sixteen packs can be carefully removed. The packs each contain 444 cells, the pack voltage is 24 V, and the energy stored is 5.3 kWh.

The video is below the break. We can’t help noticing some of the rather tasty automotive objects of desire in their lot.

Continue reading “Tesla Model S Battery Pack Teardown” →

How To Put A Jag On Your School Roof

February 28, 2017 by Jenny List 33 Comments

Did you ever commit any pranks in your time at high school, college, or university? Maybe you moss-painted a rude word on the wall somewhere, or put a design in a sports field with herbicide, or even worse, slow-release fertiliser. [Roman Kozak] and his friends went far further than that last summer when they replicated some of the most famous student pranks; they put a Jaguar S type car on the roof of their school. And now the dust has settled, he’s posted an account of how they did it.

Of course, putting a car on the roof is a significant challenge, particularly when you only have the resources of a high-school student. Ensuring the roof was strong enough for a car, and then hiring a crane to do the deed, was beyond them. They therefore decided to take the wheels and outer body panels of a car and mount them on a wooden frame to give the appearance of a car.

They needed a statement vehicle and they didn’t have a huge budget, so it took them a while to spot a for-parts Jaguar S type which when it came into their possession they found only had a fault with its reverse gear. Some hard work removed the panels, and the rest of the car was taken for scrap.

Frenetic work as the term end approached gave them their frame, and a daring midnight raid was mounted to winch the parts to the roof with a pulley. The result was so popular with their classmates and teachers that they owned up to the prank rather than preserve their anonymity. We think these young scamps will go far.

This is definitely the first car-on-roof prank we’ve brought you on Hackaday, but it’s not the first to be done. [Roman] and his friends cited an MIT prank as their inspiration, but the daddy of car-on-roof stunts has to go to Cambridge University students in the 1950s. Their Austin might be a lot smaller than the MIT Chevy or [Roman]’s Jag, but they got it onto their roof in one piece as a full car rather than a facsimile of one.

Important note: The author would like to state for the record that she and her friends were somewhere else entirely and had solid alibis when in summer 1993 the logo of Hull University Union Technical Committee appeared in the lawn outside Hull University Union. We’re sure that commenters will be anxious to set their own records straight for posterity in a similar manner.

Is Your Child A Hacker?

February 27, 2017 by Jenny List 109 Comments

Parents in Liverpool, UK, are being prepared to spot the signs that their children might be hackers. The Liverpool Echo reports on the launch of a “Hackers To Heroes” scheme targeting youngsters at risk of donning a black hat, and has an expert on hand, one [Vince Warrington], to come up with a handy cut-out-and-keep list. Because you never know when you’re going to need one, and he’s helped the Government so should know what he’s talking about.

Of course, they’re talking about “Hacker” (cybercriminal) while for us the word has much more positive connotations. And it’s yet another piece of ill-informed media scaremongering about technology that probably fits like so many others in the “People are having fun. Something Must Be Done About It!” category. But it’s still something that will probably result in hassle for a few youngsters with an interest in technology, and that’s not encouraging.

The full list is reproduced below, if you’re a parent it seems you will need to watch your children if:

They spend most of their free time alone with their computer
They have few real friends, but talk extensively to online friends about computers
Teachers say the child has a keen interest in computers, almost to the exclusion of all other subjects
They’re online so much it affects their sleeping habits
They use the language of hacking, with terms such as ‘DdoS’ (pronounced D-dos), Dossing, pwnd, Doxing, Bots, Botnets, Cracking, Hash (refers to a type of encryption rather than cannabis), Keylogger, Lulz, Phishing, Spoof or Spoofing. Members of the Anonymous Hackivist group refer to their attacks as ‘Ops’
They refer to themselves and their friends as hackers or script kiddies
They have multiple social media profiles on one platform
They have multiple email addresses
They have an odd sounding nickname (famous ones include MafiaBoy and CyberZeist)
Their computer has a web browser called ToR (The Onion Router) which is used to access hacking forums on the dark web
Monitoring tools you’ve put on the computer might suddenly stop working
They can connect to the wifi of nearby houses (especially concerning if they have no legitimate reason to have the password)
They claim to be making money from online computer games (many hackers get started by trying to break computer games in order to exploit flaws in the game. They will then sell these ‘cheats’ online).
They might know more than they should about parents and siblings, not being able to resist hacking your email or social media
Your internet connection slows or goes off, as their hacker rivals try to take them down
Some circumstantial evidence suggests children with Autism and Asperger’s could be more vulnerable to becoming hackers.

Reading the list, we can’t help wondering how many Hackaday readers would recognise as perfectly normal behaviours from their own formative years. And some of them look ripe for misinterpretation, for example your internet connection slowing down does not automatically mean that little [Jimmy] is selling a billion compromised social media accounts on the Dark Web.

Particularly concerning though is the final association of computer crime with children who are autistic or have Asperger’s Syndrome. Picking on a minority as a scapegoat for a public moral panic is reprehensible, and is not responsible journalism.

Still, you have to laugh. They remembered to include a stock photo of a hacker using a keyboard, but they’ve completely missed the telltale sign of a real hacker, which is of course wr1t1n9 11k3 r341 1337 h4xxx0rzzz.

Via The Register.

Liverpool skyline, G-Man (Public domain) via Wikimedia Commons.

Universal Radio Hacker

February 23, 2017 by Jenny List 18 Comments

If you are fascinated by stories you read on sites like Hackaday in which people reverse engineer wireless protocols, you may have been tempted to hook up your RTL-SDR stick and have a go for yourself. Unfortunately then you may have encountered the rather steep learning curve that comes with these activities, and been repelled by a world with far more of the 1337 about it than you possess. You give up after an evening spent in command-line dependency hell, and move on to the next thing that catches your eye.

You could then be interested by [Jopohl]’s Universal Radio Hacker. It’s a handy piece of software for investigating unknown wireless protocols. It supports a range of software defined radios including the dirt-cheap RTL-SDR sticks, quickly demodulates any signals you identify, and provides a whole suite of tools to help you extract the data they contain. And for those of you scarred by dependency hell, installation is simple, at least for this Hackaday scribe. If you own an SDR transceiver, it can even send a reply.

To prove how straightforward the package is, we put an RTL stick into a spare USB port and ran the software. A little investigation of the menus found the spectrum analyser, with which we were able to identify the 433 MHz packets coming periodically from a wireless thermometer. Running the record function allowed us to capture several packets, after which we could use the interpretation and analysis screens to look at the binary stream for each one. All in the first ten minutes after installation, which in our view makes it an easy to use piece of software. It didn’t deliver blinding insight into the content of the packets, that still needs brain power, but at least if we were reverse engineering them we wouldn’t have wasted time fighting the software.

We’ve had so many reverse engineering wireless protocol stories over the years, to pick only a couple seems to miss the bulk of the story. However both this temperature sensor and this weather station show how fiddly it can be without a handy software package to make it easy.

Via Hacker News.

Tales Of A Cheap Chinese Laser Cutter

February 22, 2017 by Jenny List 51 Comments

The star turn of most hackspaces and other community workshops is usually a laser cutter. An expensive and fiddly device that it makes much more sense to own collectively than to buy yourself.

This isn’t to say that laser cutters are outside the budget of the experimenter though, we’re all familiar with the inexpensive table-top machines from China. Blue and white boxes that can be yours for a few hundred dollars, and hold the promise of a real laser cutter on your table.

Owning one of these machines is not always smooth sailing though, because their construction and choice of components are often highly variable. A thorough check and often a session of fixing the non-functional parts is a must before first power-on.

[Extreme Electronics] bought one, and in a series of posts documented the process from unboxing to cutting. Starting with a full description of the machine and what to watch for out of the box, then a look at the software. A plugin for Corel Draw was supplied, along with a dubious copy of Corel Draw itself. Finally we see the machine in operation, and the process of finding the proper height for beam focus by cutting an inclined plane of acrylic.

The series rounds off with a list of useful links, and should make interesting reading for anyone, whether they are in the market for a cutter or not.

These cutters/engravers have featured here before many times. Among many others we’ve seen one working with the Mach3 CNC software, or another driven by a SmoothieBoard.

Moving Microns With A High Precision Linear Stage

February 22, 2017 by Jenny List 32 Comments

As anyone who has experimented with their own home-made CNC machinery will tell you, precision isn’t cheap. You can assemble a gantry mill using off-the-shelf threading and kitchen drawer slides. But it’s a safe assumption that if you put the tool at a particular position it won’t be quite at the same position next time you return. But if you take your budget from dirt cheap to reasonably priced you can do much better. [Adam Bender] designs high-precision automation systems for a living, so when he needed a precision linear stage for a personal project he achieved micron level accuracy for under $500.

micron-precision-linear-actuator — Red parts are the two spring-loaded nuts

He explains the problem of backlash with an inexpensive lead screw — the wiggle between threaded components that cause positional chaos. His solution uses two nuts preloaded against each other with a spring. There is still a stick-slip issue; a tendency to move in lurches due to differences between the coefficients of static and dynamic friction between the materials. Careful choice of machining stock for the nut to picking materials in which these coefficients were almost identical reduced the stick-slip to as little as possible.

He goes into significant detail on the design, manufacture, and testing of all the components of his stage, its body, sealing system, and control. If you are a precision CNC guru maybe you’ll find it interesting as a cleverly designed component, but if you are a mere dilettante you’ll find it fascinating to read a comprehensive but accessible write-up from a professional in the field.

This build probably goes a step beyond most we’ve featured in the past, but that’s not to say we’ve not seen some pretty good efforts.

A 6502 Retrocomputer In A Very Tidy Package

February 20, 2017 by Jenny List 12 Comments

One of the designers whose work we see constantly in the world of retrocomputing is [Grant Searle], whose work on minimal chip count microcomputers has spawned a host of implementations across several processor families.

Often a retrocomputer is by necessity quite large, as an inevitable consequence of having integrated circuits in the period-correct dual-in-line packages with 0.1″ spaced pins. Back in the day there were few micros whose PCBs were smaller than a Eurocard (100 mm x 160 mm, 4″ x 6.3″), and many boasted PCBs much larger.

[Mark Feldman] though has taken a [Grant Searle] 6502 design and fitted it into a much smaller footprint through ingenious use of two stacked Perf+ prototyping boards. This is a stripboard product that features horizontal traces on one side and vertical on the other, which lends itself to compactness. Continue reading “A 6502 Retrocomputer In A Very Tidy Package” →