Solder Paste How-to Tutorial

September 28, 2010 by James Munns 15 Comments

The application of Solder Paste is an essential part of short run manufacturing and prototyping. After getting back bare boards from a PCB shop, its time to get down to business and populate those boards. This new tutorial set assumes you have access to things such as stencils for your boards, but does mention a couple of resources on commercially available ways to purchase stencils. Of course, if you have a laser cutter, we can help you out. After getting your solder paste chops down, make sure you check out our guide to toaster oven reflowing.

[Thanks to P. Torrone]

Homemade Solid Propellant Rocket Motors

September 28, 2010 by Mike Szczys 42 Comments

[KoD] and [Navic] are building solid propellant motors using sugar and potassium nitrate. They cook up the two ingredients along with water and a bonding agent. They find that corn syrup is particularly good for bonding and that cooking the strange brew is more of an artform than science. Either way, the video after the break is proof of the dangers involved in this hobby. Testing the engine thrust with a bathroom scale ends badly for the scale.

There is something satisfying about the ingenuity that goes into the materials. For a casing they’re using PVC pipe, and forming a cone to focus the thrust by using a what amounts to plumber’s epoxy putty. The capping agent for the finished motor is ground up kitty litter.

This is an interesting read, but for now we’re going to stick to water rockets.

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Work For Hack A Day

September 27, 2010 by Caleb Kraft 48 Comments

HackADay.com, a well-known and respected blog dedicated to all things hardware and hacking related, is looking for knowledgeable and passionate writers to join their team of specialized and dedicated freelance writers. This is a paid, freelance position that requires professionalism, consistency, and reliability in both writing style and deliverables. We’re eager to track down and bring in some of the most passionate folks out there in the software/hardware/tech & hacking world. We pay our writers a solid per-post rate and we’re ready to take HackADay to the next level with more content across a wider array of interests and expertise. If you’re a good writer that loves the kind of stuff we talk about, then we want you to be behind the growth and dominance of this household name in hacks.

All hardware/hack/tech junkies encouraged to apply, but folks with experience in the following fields will get bonus points:

–circuitry design
–robot building
–mobile device programming
–full desktop application programming
–computer security
–gritty hardware fabrication
–modifying existing systems

If you’re ready to join HackADays’ team of top-notch freelance writers, apply through our ONLINE JOB BOARD. Formal resumes are welcome, but cover letters with links to blogs, writing samples or any portfolio work is really what we’d like to see. Here’s an idea of what to include:

A short bio about yourself
3 example daily posts written in the style of Hack a Day
3 software or hardware how-tos you’d like to see on the web. For examples of work we’ve done in the past, look at some of our project summaries, How-tos, and software tutorials.
A couple sentences on how you would improve the site either through features or content
Any additional reasons why you would make a good fit for Hack a Day

Thanks for your interest!

GPU Processing And Password Cracking

September 27, 2010 by James Munns 53 Comments

Recently, research students at Georgia Tech released a report outlining the dangers that GPUs pose to the current state of password security. There are a number of ways to crack a password, all with their different pros and cons, but when it comes down to it, the limiting factor in all of these methods is processing complexity. The more operations that need to be run, the longer it takes, and the less useful each tool is for cracking passwords. In the past, most recommendations for password security revolved around making sure your password wasn’t something predictable, such as “password” or your birthday. With today’s (and tomorrows) GPUs, this may no longer be enough.

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Wireless Electrocardiography… With IPhone

September 27, 2010 by Mike Szczys 32 Comments

This module is a sensor package for monitoring the electrical activity of the heart. It is the product of an effort to create a Wireless Body Sensor Network node that is dependable while consuming very little electricity, which means a longer battery life. To accomplish this, the microcontroller in charge of the node compresses the data (not usually done with wireless ECG hardware) so that the radio transmissions are as short and infrequent as possible.

[Igor] sent us this tip and had a short question and answer session with one of the developers. It seems they are working with the MSP430 chips right now because of their low power consumption. Unfortunately those chips still draw a high load when transmitting so future revisions will utilize an alternative.

Oh, and why the iPhone? The device that displays the data makes little difference. In this case they’re transmitting via Bluetooth for a real-time display (seen in the video after the break). This could be used for a wide variety of devices, or monitored remotely via the Internet.

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Arduino UNO And Mega 2560

September 27, 2010 by Devlin Thyne 29 Comments

The Arduino Team presented some new products at Maker Faire this weekend. It’s a significant update. The Arduino UNO and Arduino Mega 2560 update the Duemilanove and Mega respectively. They now use an ATMega8U2 instead of an FTDI USB to serial converter chip. Allowing an Arduino to become nearly any kind of USB device. A fourth mounting hole has been added to the UNO for more stable mounting. The booloader is now the Optiboot bootloader. The boards can run firmata out of the box. We are not sure about existing Arduino boards, but the last six bytes of EEPROM have a unique serial number. At this point, the Mega 2560 has some kind of issue with gcc on certain platforms and unable to use the full memory available until there is an update to the IDE.

The team also gave a preview of some works in progress. Arduino Ethernet POE can be power over ethernet and loaded with TFTP. Available October 18, TinkerKit will be released. Geared toward designers, the kit has PCB modules that include a joystick, soft pots, transistor, relay, power MOSFET, push button, LEDs and motor driver. That same day will be the launch of the multi-lingual Arduino Store.

These developments will be a nice addition to the toolset out there that you can use and we look forward to new projects using these tools.

Update: [PT] sent us a link to an ever-growing FAQ about this hardware.

Beginner Concepts: All About AVR Interrupts

September 27, 2010 by Mike Szczys 10 Comments

Microcontroller interrupts are one of the big tools in our embedded programming arsenal. They make the chip listen for particular events, and once detected they stop what they’re doing and run a separate set of code called and Interrupt Service Routine. We’ve come across two fairly new tutorials on the subject that you should check out if you’re not yet a master on the topic. One is a ProtoShack tutorial on ATmega168 external interrupts, and the other is a Newbie’s Guide to AVR Interrupts by [Dean Camera] (we’ve been a fan of his tutorials for some time). Both cover a range of topics from what interrupts are, to avoiding the common problems of volatile data types and the compiler optimization caveats.

What can you do with interrupts? External interrupts can be used to wake up a project like this LED menorah from sleep mode. Interrupts can be used to monitor a timer for a certain value or an overflow for use in generating a pulse-width modulation signal. The TI Launchpad uses an interval timer interrupt for button debouncing in projects like this code which was ported from an AVR chip. The source for both is available if you wanted to compare how the two differ.

Interrupts are powerful. Learn them, love them, use them.