So You Wanna Learn FPGAs…

December 30, 2011 by Brian Benchoff 44 Comments

FPGAs are the bee’s knees. Instead of programming a chip by telling it what to do, FPGAs allow you to tell a chip what to be. Like everything though, a new skill set is needed to fully exploit the power of FPGAs. [Mike Field] decided to give back to the internet community at large and put up a crash course in FPGA design.

Right now, [Mike] has a couple of modules up that include subjects like binary math, busses, counting, and of course setting up the FPGA hardware. The recommended hardware is the Papilio One, although the Digilent Nexys2 is what [Mike] has been using so far.

We’ve seen a ton of awesome stuff that uses FPGAs, like the emulated Mac Plus, breaking HDCP, and an Ocarina of Time. [Mike]’s tutorials look like a great starting point for some FPGA work. [Mike] is also looking for some feedback on his tutorials, so if you’ve got an idea of what he should cover be sure to drop him a line.

EDIT: ~~The server was running on an FPGA and we can’t find a cache anywhere. If you’ve found a mirror, send a message.~~ Apparently Amazon’s EC2 runs on an FPGA.

Video Series Shows How To Build Your Own Solar-charged R/C Lawnmower

December 28, 2011 by Mike Nathan 18 Comments

rc-solar-lawnmower

As winter is officially upon us, we’re pretty sure that the last thing most of you are thinking about is mowing your lawn. We would argue that it’s actually the ideal time to do so – that is, if you are interested in automating the process a bit.

[Robert Smith] has spent a lot of time thinking about his lawn, wanting a way to sit back and relax while doing his weekly trimming. He set off for the workshop to build an R/C electric lawnmower, and thoroughly documented the process in order to help you do the same.

On his web site, you will find a series of videos detailing every bit of the solar charged R/C lawnmower’s construction, taking you through the planning phases all the way to completion. [Robert] has provided just about anything you could possibly need including parts lists, schematics, code, and more.

If the short introductory video below has you interested, be sure to swing by his site for everything you need to build one of your own.

Continue reading “Video Series Shows How To Build Your Own Solar-charged R/C Lawnmower” →

An Introduction To Stepper Motors

December 1, 2011 by Brian Benchoff 17 Comments

If you’ve been reading Hack a Day for long enough, you know about our infatuation with stepper motors. These precious little devices put the oomph into our CNC routers, 3D printers, robots, and other miscellaneous projects. Steppers aren’t your run-of-the-mill motors, though. [Steaky] posted a great introduction to stepper motors that lets you hit the ground running building any moving project you could imagine.

Apart from identifying a stepper and figuring out if it works, [Steaky] goes over how to make these motors turn. The theory behind an H-bridge is easy enough, but theory isn’t something often presented in schematics or stepper driver datasheets.

We’ve pulled more than our fair share of steppers from flatbed scanners and old printers. There’s nothing wrong with scavenging old parts, and whether you’re making a robot band to play your kid’s birthday party, robochess, or one of the many 3D printers or CNC machines, there’s going to be a stepper motor in your future.

Experimenting With Bridge Rectifers For AC To DC Power Conversion

November 20, 2011 by Mike Szczys 28 Comments

The folks over at Toymaker Television have put together another episode. This time they’re looking at bridge rectifiers and how they’re used in AC to DC converters.

This is a simple concept which is worth taking the time to study for those unfamiliar with it. Since Alternating Current is made up of cycles of positive and negative signals it must be converted before use in Direct Current circuits; a process called rectification. This is done using a series of 1-way gates (diodes) in a layout called a bridge rectifier. That’s the diamond shape seen in the diagram above.

This episode, which is embedded after the break, takes a good long look at the concept. One of the things we like best about the presentation is that the hosts of the show talk about actual electron flow. This is always a quagmire with those new to electronics, as schematics portray flow from positive to negative, but electron theory suggests that actual electron flow is the exact opposite. Continue reading “Experimenting With Bridge Rectifers For AC To DC Power Conversion” →

Beginner Concepts: We’re Gonna Let You Finish, But First This Tutorial On Arduino Interrupts

November 8, 2011 by Jesse Congdon 13 Comments

OK, year-old pop culture references aside [Kyle] dropped us a line to show us his tutorial on using interrupts with your Arduino. Given the single core nature of your average Arduino’s AVR you pretty much have two choices for monitoring occasional un-timed inputs: Either check an input at an interval (which risks missing the signal entirely) or set up an interrupt to pause the chip’s normal operation. Obviously working with interrupts saves you tons of clock cycles since you are not polling a pin over and over. [Kyle] plans on a follow up tutorial to cover timer based interrupts, which can come in handy when generating frequencies and stuff.

Looking for more Arduino Basics? How about Basic on an Arduino. Check out our other beginner concepts posts as well if you need to work on your fundamentals.

Altoid Tin Etching Tutorial

October 23, 2011 by Brian Benchoff 20 Comments

Eminent steampunker [Jake Von Slatt] wrote a small article on etching candy tins for The Steampunk Bible, but the limited space available in the book didn’t allow for a full exposition. To make amends for his incomplete tutorial, he posted this walk through to compliment the Bible’s article.

The process is very similar to the many tutorials we’ve seen on home-etching PCBs using the toner transfer method. Removing the paint from the Altoid tin, creating a mask, printing it on the Sunday circulars, and taking an iron to the tin is old hat for home fabbers.

Unlike PCB manufacturing, [Mr. Von Slatt] doesn’t bother with Ferric Chloride or other nasty chemicals – he does everything with electrolysis. After adding a few tablespoons of table salt to a bucket of water, [Jake] takes a DC power supply and connects the positive lead to the lid and the negative lead to the base. a bit of electrical tape around the corners of the lid keeps the metal from getting too thin.

A nice Copper finish can be applied to a finished tin by swabbing on a solution of Copper Sulfate – a common ingredient in “Root Kill” products. Of course that’s not a necessary step; you can easily enjoy and elegant Altoid tin bare metal.

Cheap Acoustic Panel DIY

October 21, 2011 by Jesse Congdon 37 Comments

[Eric Wolfram] wrote in to let us know about a simple and cheap acoustic panel DIY he put together. When installing a home theater acoustics are often neglected (especially if you spend so much on the TV you cannot afford any furniture for the room) resulting in reduced listening quality and poor spacial sound imaging from your surround system (also responsible for the furniture problem). The addition of sound absorbing panels helps control the acoustics of the room and may even class up the place a bit. These are also come in handy for home studio usage where a low level of reverberation is preferred.

The panels are relatively simple to produce on a budget, just a sheet of 2″ thick dense fiberglass board glued into a wooden frame and covered in a sound-transparent fabric. [Eric] goes into a lot of the material selection process to help you along your way. The best part about the project (aside from its obvious utility) is that all of the materials can be found cheaply at your average home improvement store, with the exception of the fabric. [Eric] mentions that you can substitute colored burlap if need be. Once the panel is assembled and glued it just has to be hung on the wall of your choice like a large heavy picture frame. This could certainly help the acoustics and reduce some slap-back echo in your warehouse/shop. We might have to try this one over the weekend.

Thanks [Eric]!