Author: Bryan Cockfield

1870 Articles

EPROM Timer

April 7, 2016 by 29 Comments

[glitch] had a cheap EPROM eraser with very few features. Actually, that might be giving it too much credit: it’s barely more than a UV light that turns on when it’s plugged in and turns off when it’s plugged out unplugged. Of course it would be nice to implement some safety features, so he decided he’d hook it up to a software-controlled power outlet.

Of course, controlling a relay that’s wired to mains is old hat around here, and in fact, we’ve covered [glitch]’s optoisolated mains switch already. He’s gone a little beyond the normal mains relay project with this one, though. Rather than use a microcontroller to run the relay, [glitch] wrote a simple Ruby script on his computer to turn the EPROM eraser on for the precise amount of time that is required to erase the memory.The Ruby script drives the relay control directly over a USB to serial adapter’s RTS handshake pin.

[glitch]’s hack reminds us that if you just need a quick couple bits of slow output, a USB-serial converter might be just the ticket. You could imagine driving everything from standard lamps to your 3D printer’s bed heater (provided you use similar hardware), but it’s especially helpful for [glitch] who claims to forget to turn off the eraser when it’s done its job, which leaves a potentially dangerous UV source just lying about. It’s always a good idea to add safety features to a dangerous piece of equipment!

Hand Gestures Drive Car

April 5, 2016 by 8 Comments

There are a number of ways to control an automobile without using the pedals, and sometimes even without using the steering wheel. Most commonly these alternative control mechanisms are installed in vehicles whose owners are disabled in some way, but [Anurag] has taken this idea of alternative control one step further. He has built a car that can be driven by hand gestures alone.

On a remote controlled car, a Raspberry Pi 2 was installed that handles processing and communication. A wireless network is created on the Pi, and a laptop connects to the Pi over the network. The web camera on the laptop regularly captures frames at 15 fps to check for the driver’s hand gestures. The image is converted to gray scale, thresholded, contours are obtained, and the centroid and farthest points are obtained.

After some calculations are done, a movement decision is taken. The decision is passed to the Pi, which in turn, passed that to the internal chip of the car. All of the code is available on the project’s github page. [Anurag] hopes that this can be scaled up to full sized cars in the future. We’ve seen gesture-based remote controls before that rely on Sonar sensors, so it’s interesting to see one that relies strictly on image processing.

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Tiny Hotplate Isn’t Overkill

April 1, 2016 by 31 Comments

When working on a new project, it’s common to let feature creep set in and bloat the project. Or to over-design a project well beyond what it would need to accomplish its task. Over at Black Mesa Labs, their problem wasn’t with one of their projects, it was with one of their tools: their hot plate. For smaller projects, an 800W hot plate was wasteful in many ways: energy, space, and safety. Since a lot of their reflow solder jobs are on boards that are one square inch, they set out to solve this problem with a tiny hot plate.

The new hot plate is perfectly sized for the job. Including control circuitry, it’s around the size of a credit card. The hot plate is powered from a small surplus 20V 5A laptop power supply and does a nice 4 minute reflow profile and cools off completely in under a minute. Compared to their full-sized hot plate, this is approximately 29 minutes faster, not to mention the smaller workspace footprint that this provides. The entire setup cost about $20 from the heating element to the transistors and small circuit board, and assuming that you have an Arduino Pro sitting in your junk bin.

It’s a good idea to have a reflow oven or a hot plate at your disposal, especially if you plan to do any surface mount work. There are lots of options available, from re-purposed toaster ovens to other custom hot plates of a more standard size. Overkill isn’t always a bad thing!

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White Oak Illuminated Bluetooth Speaker

March 28, 2016 by 15 Comments

Besides being common tools available to most hackers and makers out there, 3D printing, CNC machines, and cheap Chinese electronics have one more things in common: they were all used by [Nick] to build a bluetooth speaker system that has some interesting LED effects built into the case.

This is fresh on the heels of another hack that used similar construction methods to build a “magic” wood lamp. [Nick] takes it a step further, though. His case is precisely machined in white oak and stuffed with the latest China has to offer: a bank of lithium-ion batteries, a DC-DC converter to power the amplifier, and a Bluetooth module. After some sanding, the speakers look professional alongside the blue light features hiding behind the polycarbonate rings.

Of course you’ll want to visit the project site for all the details of how [Nick] built his speaker case. He does admit, however, that the electronics are fairly inefficient and need a little work. All in all though, it’s a very refined set of speakers that’ll look great on a bookshelf or on a beach, workshop bench, or anyplace else that you could take them.

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Museum Shows Off Retro Malware

March 25, 2016 by 21 Comments

There’s some debate on which program gets the infamous title of “First Computer Virus”. There were a few for MS-DOS machines in the 80s and even one that spread through ARPANET in the 70s. Even John von Neumann theorized that programs might one day self-replicate. To compile all of these early examples of malware, and possibly settle this question once and for all, [Mikko Hypponen] has started collecting many of the early malware programs into a Museum of Malware.

While unlucky (or careless) users today are confronted with entire hard drive encryption viruses (or worse), a lot of the early viruses were relatively harmless. Examples include Brain which spread via floppy disk, the experimental ARPANET virus, or Elk Cloner which, despite many geniuses falsely claiming that Apples are immune to viruses, infected Mac computers of the 80s. [Mikko] has collected many more from this era that can be downloaded or demonstrated in a browser.

Retrocomputing is an active community, with users keeping gear of this era up and running despite it being 30+ years old. This software, while malicious at the time, is a great look into what the personal computing world was like in its infancy. And don’t forget, if you have a beige computer from a bygone era, you can always load up our Retro Page.

Thanks to [chad] for the tip!

KiCAD BOM Management

March 16, 2016 by 17 Comments

KiCAD remains a popular tool for designing PCBs and other circuits, and with good reason: it’s versatile and it’s got pretty much everything needed to build any type of circuit board you’d want. It also comes with a pretty steep learning curve, though, and [Jeff] was especially frustrated with the bill of materials (BOM) features in KiCAD. After applying some Python and Kivy, [Jeff] now has a BOM manager that makes up for some of KiCAD’s shortcomings.

Currently, the tool handles schematic import, like-component consolidation, and a user-managed parts database that can be used to store and retrieve commonly used parts for the future. All of the changes can be saved back to the original schematic. [Jeff] hopes that his tool will save some time for anyone who makes more than one PCB a year and has to deal with the lack of BOM features native to KiCAD.

[Jeff] still has some features he’d like to add such as unit tests, a user guide, and a cleaner user interface. What other features are you anxious to see added to KiCAD?

This script is a great tool for anyone who has had similar frustrations. KiCAD is popular to modify and expand, too: there have been tools for mechanical CAD export, a parts-generator and cost-tracker, and an Eagle to KiCAD converter if you’re thinking of making the switch.

Nessie, The Educational Robot

February 27, 2016 by 6 Comments

At the Lifelong Learning Robotics Laboratory at the Erasmo Da Rotterdam in Italy, robots are (not surprisingly) used to teach all of the fundamentals of robotics. [Alessandro Rossetti] and the students at the lab have been at it for years now, and have finally finished their fifth generation of a robot called Nessie. The big idea is to help teach fundamentals of programming and electronics by building something that actually uses these principles.

The robot is largely 3D printed and uses an FPGA to interact with the physical world through a set of motors and sensors. The robot also uses a Raspberry Pi to hold the robot’s framework. The robot manages the sensors in hardware with readers attached to the CPU AXI bus. The CPU reads their values from memory space, though, so the robot is reported to be quite quick.

The lab is hoping to take their robot to a robotics competition in Bari, Italy. We hope that they perform well there, since we are big fans of any robot that’s designed to teach anyone about robotics and programming. After all, there are robots that help teach STEM in Africa, robots that teach teen girls about robots, and robots that teach everyone.