What if there was a job where you built, serviced, and prepared science demonstrations? This means showing off everything from principles of physics, to electronic theory, to chemistry and biology. Would you grab onto that job with both hands and never let go? That was my reaction when I met [Dan Rosenberg] who is a Science Lecture Demonstrator at Harvard University. He gave me a tour of the Science Center, as well as a behind the scenes look at some of the apparatus he works with and has built.
Need a simple fab process to go from a humble vector graphic to a final part — in a matter of minutes? The CO2 laser cutter might be the right choice. As these tools open themselves up to widespread use through hackerspaces, I decided to give Delrin some well-deserved time under the spotlight.
This guide is a brief collection of tips and techniques that I’ve either learned from others or discovered on my own over the last couple years working with laser-cut Delrin (a.k.a Acetal) for functional prototypes. I hope this guide serves you well as we keep exploring the limits of the material.
As a disclaimer, keep in mind that in no way are these techniques unique or limited to Delrin. Many are not only years old but also common practice in either engineering design or the local machine shop. This article simply highlights the techniques shown here that perform both repeatably and predictably with Delrin and a couple hand-tools, and I hope to share them with a growing audience of laser cutter enthusiasts.
Join us for a Meetup on Saturday, September 12th near Washington DC. The Hackaday Crew is headed out to the DC area a week from Saturday and we want to hang out with you. We’ll be hosting a meetup at Nova Labs hackerspace in Reston, Virgina which is on the Northwest side of DC.
We’ll get things rolling at 6pm on Saturday, September 12. The event includes a few lightning talks, some food and drink, and a lot of socializing. This is free to all but you do need to RSVP to let us know you’re coming. We want you to bring a hack to show off. We love to see what people are working on no matter the level of complexity or stage of completion.
This all started when [Anool Mahidharia] mentioned that he’d be at Nova Labs on September 11-13 to lead a KiCAD PCB design workshop. This 2.5 day boot-camp starts with installing the Open Source EDA software on your laptop and ends when you have a completed PCB design ready to be submitted to a board fab. There is a charge for the workshop and attendance is limited so if you’re interested in it you should sign up now. Our events page is a good collection of information on both events as well as directions to get to Nova Labs.
The workshop is being organized by our friend [Bob Coggeshall] who we first met (and interviewed about his work on the Linux ‘sudo’ command) back in 2014 at Bay Area Maker Faire. Since then, [Brian Benchoff] swung by and visited [Bob] to talk about his company Small Batch Assembly and to tour Nova Labs. He will be conducting his own surface mount soldering workshop, will speak about Design For Manufacturing, and will show his Pick and Place machine during the weekend.
It will be fun to visit with [Bob] and to meet everyone who can make it to the Saturday evening meetup. So far [Mike Szczys], [Brian Benchoff], and [Sophi Kravitz] are all planning to be there. [Anool Mahidharia] will of course be there since he’s leading the workshop. The following weekend [Anool] and [Brian] will both be headed to Philadelphia for the 2015 Open Hardware Summit for which Hackaday is a proud sponsor. [Matt Berggren] and [Amber Cunningham] will both be at OSH as well, talking all things Tindie.
If you have a 3D printer, it is a good bet you’ve at least seen or heard of Tinkercad. There’s pros and cons to doing your design in a Web browser, but Tinkercad is very easy to use and great for making simple objects. However, there are other 3D object designers you can use in your browser, too. Tinkercad is just the one that everyone seems to know about.
I won’t talk much about Tinkercad, but if you haven’t tried it, it is well worth a look. It has a simple system of drawing things and holes. When you merge holes with things you can make lots of shapes. The alignment tools are good, and since Autodesk acquired them (part of its 123d app suite), it isn’t likely they will go under any time soon (which, as you may remember, almost happened).
If you are designing some great new secret invention you may shy away from cloud-based design programs. But if you are printing out key chains with your coworker’s cat’s name on it, do you really care? Most of these cloud-based programs will work from any computer so you can quickly do a design in a coffee shop and then go home and print it.
Finishing up on the topic of CMOS bus logic I am going to show a couple of families with unique properties that may come in handy one day.
High Voltage Tolerant Family: AHC/AHCT
First up is a CMOS logic family AHC/AHCT that has one of the protection diodes on the input removed. This allows a 5V input voltage to be applied to a device powered by 3.3V so that I don’t have to add a gate just for the translation. Any time I can translate and do it without any additional gate delays I am a happy engineer.
Of course the example above works in a single direction and bidirectional does start to get more complicated. Using a bidirectional buffer such as a 74AHCT245 will work for TTL translation when going from 3.3V back to 5V providing there is a direction control signal present.
Every year, more than 30,000 people are killed in motor vehicle accidents in the US, and many many more are injured. Humans, in general, aren’t great drivers. Until dependable self-driving cars make their way into garages and driveways across the country, there is still a great amount of work that can be done to improve the safety of automobiles, and the best hope on the horizon is Vehicle to Vehicle communications (V2V). We keep hearing this technology mentioned in news stories, but the underlying technology is almost never discussed. So I decided to take a look at what hardware we can expect in early V2V, and the features you can expect to see when your car begins to build a social network with the others around it.
With the summer’s big security conferences over, now is a good time to take a look back on automotive security. With talks about attacks on Chrysler, GM and Tesla, and a whole new Car Hacking village at DEF CON, it’s becoming clear that autosec is a theme that isn’t going away.
Up until this year, the main theme of autosec has been the in-vehicle network. This is the connection between the controllers that run your engine, pulse your anti-lock brakes, fire your airbags, and play your tunes. In most vehicles, they communicate over a protocol called Controller Area Network (CAN).
An early paper on this research [PDF] was published back in 2010 by The Center for Automotive Embedded Systems Security,a joint research effort between University of California San Diego and the University of Washington. They showed a number of vulnerabilities that could be exploited with physical access to a vehicle’s networks.
A number of talks were given on in-vehicle network security, which revealed a common theme: access to the internal network gives control of the vehicle. We even had a series about it here on Hackaday.
The response from the automotive industry was a collective “yeah, we already knew that.” These networks were never designed to be secure, but focused on providing reliable, real-time data transfer between controllers. With data transfer as the main design goal, it was inevitable there would be a few interesting exploits.