When Jeffrey Brian “JB” Straubel built his first electric car in 2000, a modified 1984 Porsche 944, powered by two beefy DC motors, he did it mostly for fun and out of his own curiosity for power electronics. At that time, “EV” was already a hype among tinkerers and makers, but Straubel certainly pushed the concept to the limit. He designed his own charger, motor controller, and cooling system, capable of an estimated 288 kW (368 hp) peak power output. 20 lead-acid batteries were connected in series to power the 240 V drive train. With a 30-40 mile range the build was not only road capable but also set a world record for EV drag racing.
The “Electric Porsche 944” – by JB Straubel
The project was never meant to change the world, but with Tesla Motors, which Straubel co-founded only a few years later, the old Porsche 944 may have mattered way more than originally intended. The explosive growth between 2000 and 2010 in the laptop computer market has brought forth performance and affordable energy storage technology and made it available to other applications, such as traction batteries. However, why did energy storage have to take the detour through a bazillion laptop computers until it arrived at electro mobility?
You certainly won’t find that grail of engineering by just trying hard. Rather than feverishly hunting down the next big thing or that fix for the world’s big problems, we sometimes need to remind ourselves that even a small improvement, a new approach or just a fun build may be just the right ‘next step’. We may eventually build all the things and solve all the problems, but looking at the past, we tend to not do so by force. We are much better at evolving our ideas continuously over time. And each step on the way still matters. Let’s dig a bit deeper into this concept and see where it takes us.
Long ago, when I wanted a plywood sheet, I would go to the local big box hardware store and buy whatever was at the center of the optimization curve for cheapest and nicest looking. I would inevitably suffer with ultra-thin veneers on the top, ugly cores, unfinishable edges, warping, voids, and other maladies of the common plywood. One day I said enough is enough and bothered the salesman at my local lumber supply until he showed me one that wasn’t awful.
There are subtle clues that the Baltic Birch I’ve purchased is Russian.
Baltic birch differs from other plywoods in a few ways. Regular plywood is usually made locally from the cheapest possible core wood in alternating grain layers laminated together with a hardwood veneer on the top. There are interior and exterior grades. The exterior grades are usually made with a different glue, but don’t necessarily denote a higher quality or stability. Some of the glues used can be toxic. Wear a respirator. In normal plywood, the ATSM or BB standards only apply to the face veneers used to finish the product. The core can be of whatever quality is convenient for the manufacturer.
True Baltic Birch is made in the Baltic Region with the biggest producers being Russia and Finland. Outside of the US it is sometimes called Finnish Birch or Russian Birch plywood for this reason. It is made from only top quality birch veneers laminated together with no filler wood. It is also unique in the care taken to make sure each layer of the wood is patched so there are no voids. All Baltic Birch is made with exterior grade glue, and when properly sealed will work for outdoor applications. There are grades of Baltic birch for marine applications and exceptionally void free aircraft grade plywood at a much higher cost.
The easiest way to spot Baltic Birch if you’re American is its form factor. Baltic birch comes in 1525 x 1525 mm squares, which approximates to 5 ft x 5 ft. Some people have said that manufacturers have started to produce 4 ft x 8 ft sheets specifically for the North American market, but this information comes with a caveat that these are usually lower grades made locally or in China parading under the name. The metric form factor extends to the thicknesses of the sheets. In America they will be sold as inch, but fit pretty closely to a metric form.
3 mm ≈ 1/8″ (3 plies)
6 mm ≈ 1/4″ (5 plies)
9 mm ≈ 3/8″ (7 plies)
12 mm ≈ 1/2″ (9 plies)
18 mm ≈ 3/4″ (13 plies) – From [3] Ultimate guide to Baltic birch.
The core of regular hardware store plywood. Pretty bad in comparison.
There are some really nice practical features of Baltic Birch. One of my favorites is the absolute uniformity of the layers. This means that two pieces of birch can be laminated together and the seam between the two becomes indistinguishable. I’ve used this to make cases by CNC routing out the inside of a sheet of Baltic birch, drilling some holes for alignment pins, and then laminating the whole assembly together. We’ve covered a few readers who have had similar ideas. Since the layers are uniform you can also do interesting things when combined with a CNC router. For example, carefully milling away the layers you can get a topographic map of the object.
Baltic Birch is also significantly flatter and more stable than other plywood options. It is commonly the material used for fences on expensive tables saws. It moves less during temperature swings and changes in ambient moisture. This is one of the reasons it’s popular with fine furniture builders. This also makes Baltic birch a good option for home CNC builds, certainly better than MDF . Due to the higher quality wood and better manufacturing it is quite strong as well. It is a great structural wood.
Explanation of the grading scale for Baltic Birch from [1] Dan’s hobbies.Baltic birch holds stains very well on both its faces and its edges. It’s as easy to paint and glue as any wood. As far as surface finish goes it’s important to note that as mentioned previously, Baltic Birch is graded to a different scale than regular plywood. The grades will determine how the face veneers are treated. B/B is the highest grade with both sides being defect free. B/BB is much more common and is what you are likely to find. I have not found C or CP grades in the US. My guess is that we have plenty of low grade plywoods to compete with it. It is likely found nearer to the areas where it is produced.
This is on the non-finishing side of a Baltic Birch panel. You can see the care taken to fix knots and voids. This will be done through the whole sheet. The face of the board will not have marks. This is a B/BB grade sheet. If it was B/B both sides would be without patches.
Baltic birch is more expensive than the regular grade stuff. So a sheet of ¾” thick Oak veneer plywood with a pine core, interior grade, from Lowes is about 35 US dollars where a similar sheet of 18mm Baltic Birch will run around 65 dollars.
I’ll still occasionally purchase a cheaper sheet of plywood when I have a non-critical application (like garage shelving), but when I am doing something precise or nice I’ll spend the extra on the birch plywood. While I love this material, I am by no means a wood worker. Have any of you had experience with this plywood? Is there an even better plywood out there?
I’ve left my sources below for further reading. [3] Ultimate Guide to Baltic Birch is very good.
It’s a fair assumption that the majority of Hackaday readers will be used to working with electronic components, they are the life blood of so many of the projects featured here. In a lot of cases those projects will feature very common components, those which have become commoditized through appearing across an enormous breadth of applications. We become familiar with those components through repeated use, and we build on that familiarity when we create our own circuits using them.
All manufacturers of electronic components will publish a datasheet for those components. A document containing all the pertinent information for a designer, including numerical parameters, graphs showing their characteristics, physical and thermal parameters, and some application information where needed. Back in the day they would be published as big thick books containing for example the sheets for all the components of a particular type from a manufacturer, but now they are available very conveniently online in PDF format from manufacturer or wholesaler websites.
A 2N3904 in a TO92 through-hole package
Datasheets are a mine of information on the components they describe, but sometimes they can be rather impenetrable. There is a lot of information to be presented, indeed when the device in question is a highly integrated component such as a DSP or microprocessor the datasheet can resemble a medium-sized book. We’re sure that a lot of our readers will be completely at home in the pages of a datasheet, but equally it’s a concern that a section of the Hackaday audience will not be so familiar with them and will not receive their full benefit. Thus we’re going to examine and explain a datasheet in detail, and hopefully shed some light on what it contains.
The device whose datasheet we’ve chosen to put under the microscope is a transistor. The most basic building block of active semiconductor circuits, and the particular one we’ve chosen is a ubiquitous NPN signal transistor, the 2N3904. It’s been around for a very long time, having been introduced by Motorola in the 1960s, and has become the go-to device for a myriad circuits. You can buy 2N3904s made by a variety of manufacturers all of whom publish their own data sheets, but for the purposes of this article we’ll be using the PDF 2N3904 data sheet from ON Semiconductor, the spun-off former Motorola semiconductor division. You might find it worth your while opening this document in another window or printing it out for reference alongside the rest of this article.
Let’s take a look at all the knowledge enshrined in this datasheet, and the engineering eye you sometimes need to assign meaning to those numbers, diagrams, and formulas.
The Jargon File describes a wizard as someone who groks something to a very high degree, or the kind of person that builds a polymer concrete CNC machine with a pneumatic tool changing spindle that they designed by themselves. It makes you think that maybe Tony Stark COULD build it in a cave with scraps.
It’s a five part video series showing snippets of the build process. The last video gives an overview of the design of the machine. It is all very much in German, so if you speak German and we got anything wrong about the machine or missed anything cool, please fill us in down in the comments.
The machine starts with a 1500 kg polymer concrete pour with some steel stock embedded in it. It is then machined within an inch mm of its life as shown by practically zero deviation over its length when measured against a granite block. The wizard then goes on to make his own spindle, get castings made, and more. We liked his flowery kitchen hotplate, which he used to heat the bearings for an interference fit. It added a certain amount of style.
Unfortunately the videos don’t show the machine running, but we assume this sort of person is happily building arc reactors, power suits, and fighting crime. They probably don’t have time to film “CNC Bearbeitungszentrum im Eigenbau Teil 5”. Videos after the break.
Blood doping is so last decade! The modern cyclist has a motor and power supply hidden inside the bike’s frame.
We were first tipped off to the subject in this article in the New York Times. A Belgian cyclocross rider, Femke Van den Driessche, was caught with a motor hidden in her bike.
While we don’t condone sports cheating, we think that hiding a motor inside a standard bike is pretty cool. But it’s even more fun to think of how to catch the cheats. The Italian and French press have fixated on the idea of using thermal cameras to detect the heat. (Skip to 7:50 in the franceTVsport clip.) We suspect it’s because their reporters recently bought Flir cameras and are trying to justify the expense.
The UCI, cycling’s regulatory body, doesn’t like thermal. They instead use magnetic pulses and listen for the characteristic ringing of a motor coil inside the frame. Other possibilities include X-ray and ultrasonic testing. What do you think? How would you detect a motor inside a bike frame or gearset?
Today marks the beginning of the Anything Goes challenge, a 2016 Hackaday Prize contest that will reward 20 finalists with $1000 for solving a technology problem and a chance at winning the entire Hackaday Prize: $150,000 and a residency at the Supplyframe Design Lab in Pasadena.
The Hackaday Prize is empowering hackers, designers, and engineers to use their time to Build Something that Matters. For the next five weeks what matters is solving a technology problem. Have an idea to power vehicles without polluting the atmosphere? Great! Want to figure out how to get your washing machine to work better? We want to see that too. Anything goes so design it, prototype it, document it and you could be one of the twenty entries headed to the final round.
We have already seen a groundswell of progress in the Hackaday Prize. The first round, Design Your Concept, had over five hundred entries! But today is a brand new day, a new challenge, and all bets are off. It’s the perfect clean slate for you to join the movement.
Start your project right now and submit it to the Hackaday Prize. If you have previously started a project page you can add it to the Anything Goes challenge using the “Submit Project To” dropdown menu on the left sidebar of your project page.
Talk about your idea, document your plan for seeing it through to completion, and then start writing build logs as you begin to work on the prototype. On May 30th our panel of judges will review all the entries and choose twenty that exhibit the best the Hackaday Prize has to offer.
You have the talent. You can make the time. You will make a difference. The greatest things in the world start small but with passion. This is your moment, now start your journey.
He starts with the simplest. Which is to purchase an off the shelf web camera, and hook it up to software built to do the task. The first software he uses is the free, iSpy open source software. This adds basic features like motion detection, time stamping, logging, and an interface. He also explores other commercial options.
Next he delves a bit deeper. He starts by making a simple motion detector. When the Arduino detects motion using a PIR sensor it gets a computer to text an alert. After the tutorial begins to veer a little and he adds his WiFi light bulbs to the mix. Now he can send an email and change the color of the lights.
We suppose, that from a security standpoint. It would really freak a burglar out if all the lights turned red when they walked into a room. Either way, there’s definitely a fun weekend project in playing around with all these systems.
