Taming the Beast: Pro-Tips for Designing a Safe Homebrew Laser Cutter

Homebrew laser cutters are nifty devices, but scorching your pals, burning the house down, or smelling up the neighborhood isn’t anyone’s idea of a great time. Lets face it. A 60-watt laser that can cut plastics offers far more trouble than even the crankiest 3D-printers (unless, of course, our 3D printed spaghetti comes to life and decides to terrorize the neighborhood). Sure, a laser’s focused beam is usually pointed in the right direction while cutting, but even an unfocused beam that reflects off a shiny material can start fires. What’s more, since most materials burn, rather than simply melt, a host of awful fumes spew from every cut.

Despite the danger, the temptation to build one is irresistible. With tubes, power supplies, and water coolers now in abundance from overseas re-sellers, the parts are just a PayPal-push away from landing on our doorsteps. We’ve also seen a host of exciting builds come together on the dining room table. Our table could be riddled with laser parts too! After combing through countless laser build logs, I’ve yet to encounter the definitive guide that tells us how to take the proper first steps forward in keeping ourselves safe while building our own laser cutter. Perhaps that knowledge is implicit to the community, scattered on forums; or perhaps it’s learned by each brave designer on their own from one-too-many close calls. Neither of these options seems fair to the laser newb, so I decided to lay down the law here.

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Sage Advice for the New Ham

If you’re on the edge about getting your amateur radio license, just go do it and worry about the details later. But once you’ve done that, you’re going to need to know a little bit about the established culture and practices of the modern ham — the details.

Toward that end, [McSteve] has written up a (so far) two-part introductory series about ham radio. His first article is fairly general, and lays out many of the traditional applications of ham radio: chatting with other humans using the old-fashioned analog modes. You know, radio stuff.

The second article focuses more on using repeaters. Repeaters can be a confusing topic for new radio operators: there are two frequencies — one for transmitting and one for receiving — and funny control tones (CTCSS) etc. This article is particularly useful for the new ham, because you’re likely to have a relatively low powered radio that would gain the most from using a repeater, and because the technology and traditions of repeater usage are a bit arcane.

So if you’re thinking about getting your license, do it already. And then read through these two pages and you’re good to go. We can’t wait to see what [McSteve] writes up next.

Amazingly Detailed Robotics Ground Vehicle Guide

[Andrey Nechypurenko] has put together an excellent design guide describing the development of his a20 grou1nd vehicle and is open sourcing all the schematics and source code.

20150627_180534One of [Andrey]’s previous designs used a Pololu tracked chassis. But this time he designed everything from scratch. In his first post on the a20, [Andrey] describes the mechanical design of the vehicle. In particular focusing on trade-offs between different drive systems, motor types, and approaches to chassis construction. He also covers the challenges of using open source design tools (FreeCAD), and other practical challenges he faced. His thorough documentation makes an invaluable reference for future hackers.

[Andrey] was eager to take the system for a spin so he quickly hacked a motor controller and radio receiver onto the platform (checkout the video below). The a20s final brain will be a Raspberry Pi, and we look forward to more posts from [Andrey] on the software and electronic control system.

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What is this thing called Linux?

It should come as no surprise that we at Hackaday love Linux above all others (that should start a nice little flamewar on the internal email list). If you still haven’t given it a whirl yet, don’t fear. Everyone starts from scratch at some point. With each passing year it becomes more and more likely that knowing something about Linux will eventually benefit every hardware hacker. Take part of your time off in the coming weeks to give it a whirl. First thing’s first, check out this quick guide on what Linux actually is.

Adafruit’s offering is pretty low level, so if you’re the kind that likes to argue “kernel” versus “OS” please keep it to yourself. For us the important distinction pointed out here is microcontroller (Arduino) versus Raspberry Pi. The Pi generally runs one flavor or another of Linux for good reasons, while microcontroller-driven systems tend to run use-specific code (with the exception of projects that leverage Real Time Operating Systems). Of course it extends past pre-fab options, Linux is a popular choice on bare-bones roll-your-own machines.

This is the year of Linux! Ha, we’ve heard that one every year for at least a decade. To us it makes no difference, you should know a bit about each OS out there. What are you waiting for? Read the guide then download (for free!) a CD image of our current favorite Linux flavor.

Hackaday’s Guide to Shanghai

We happened to be in Shanghai for Electronica trade fair this year and had a great time exploring heavy industrial gear and fantasizing about all the things we could do with it. However, we simply couldn’t ignore the fact that there was a whole city out there that we’re completely missing out on. So after less than a day of being surrounded by businesspeople and Miss Universe-dressed promoters, we decided to pack our bags and hit the streets.

The question was, where should we go? Finding interesting things in a city that keeps shapeshifting (the whole Shanghai skyline did not exist 20 years ago) can be a challenge. Fortunately, our friend [David Li] gave us a list:

  1. Xin Che Jian
  2. Jiu Xing market
  3. Beijing Lu electronic market
  4. Qiujiang Lu CNC/lasercut market
  5. DFRobot.com

…and off we were.

 

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Guide for working with AVR microcontrollers

[Q] wrote in to let us know about the AVR-Guide he’s been working on. It looks like he’s finished posting about 80% of the content he planned for in his initial draft outline. We read through several of the sections and found them to be concise, yet able to present information in a way that’s easy to grasp. The screenshot above shows the most basic block of information to get started with AVR microcontrollers. We’ve covered the same information in our AVR tutorial series and think that reading through both will give you a strong understanding of the knowledge needed to work with 8-bit microcontrollers with confidence. But this resource doesn’t stop after the basics. If you’re looking to bolster your knowledge of all the features the AVR line has to offer there’s also sections explaining Digital I/O, Interrupts, Timers, Analog I/O, Communications, and Miscellaneous topics.

The site is called QEEWiki. We logged in using a Google account (this is hosted as a Google site) but didn’t see a way to edit the information. If this truly is a Wiki and you know how to edit pages please leave a comment about it after the break.

Guerilla guide to CNC machining

[Ian] wrote in to tell us about the Guerilla Guide to CNC Machining and Resin Casting. He came across it in the reference links to another project and says he wish he knew about it a long time ago. We took a look and there’s a mountain of useful information in the guide, which is written by [Michal Zalewski]. We won’t pretend that we’ve read the whole thing, there’s days worth of information here. But we will. The range of topics includes types of milling machines, milling materials, software options and use, safety, and the list goes on. Bookmark this (don’t forget the second volume), it might be just the thing to get you through the holiday with your family.