Birmingham-Based Electronics Design Nook

Steve Karg of Birmingham, AL, recently submitted info about his well-planned, cost-conscious design nook where he builds lighting control products, develops software, tests and debugs his projects, and more. The workspace is compact yet intelligently stocked with essentials such as a laptop, a scope, a toaster, a magnifier, a labelled parts bin, an AC source, and more.

Karg writes:

Here is a photo of my electronics workspace in my cellar. I use the toaster oven for soldering surface mount parts to printed circuit boards, the scope and meters for the usual diagnostics and validation, the AC source for developing line voltage dimming and switching lighting control products, the laptop for developing software including the open source BACnet Stack and Wireshark, and the light tent for deriving dimming curves for various lamps.  I bought the chairs and lab bench at a Martin-Marietta yard sale in Colorado, and they moved 3 times with me to Pennsylvania, Georgia, and now Alabama. I found the Metcal soldering iron in a dumpster in Maryland near an office building.—Steve Karg, Birmingham, AL

Steve Karg’s circut cellar in Birmingham, AL

In addition to placing his essential tools within reach, Karg did a few things we think every designer should consider when planning his or her workspace.

One, Karg neatly labelled the parts box located on the right side of the shelf above his workbench. Label now and you’ll thank yourself later.

Two, Karg has deep, sturdy, wall-mounted shelves above his workbench. As you can see, they’re capable of holding fairly large bins and boxes. They aren’t flimsy 8″ deep shelves intended for displaying lightweight curios or paperback books. If you’re planning a workspace, consider following Karg’s lead by installing sturdy shelving capable of holding everything from electronic equipment to every copy of Circuit Cellar since 1988.

Three, we applaud Karg’s magnification and lighting equipment. A cellar can be dark place, especially if it is completely underground and isn’t a “walkout” (or “daylight basement”) with a windowed door. Many basements have only a few small hopper windows that enable daylight and fresh air to get inside. In such spaces, darkness and shadows can be problematic for electrical engineers and electronics DIYers working on small projects. Without a properly placed light or lighting system, your body can overshadow your work. Good luck trying taking a close look at a board or attempting to repair a PCB trace without proper lighting. It’s clear Karg has proper lighting in mind. As you can see, he has plenty of lamps and light sources at his disposal.

And finally, kudos to Karg for purchasing the bench at a yard sale and staying with the discarded soldering iron he found in a dumpster. We all know the saying: “If ain’t broke, don’t fix it.” We agree, except when what’s broke is mounted on your circuit board, of course!

Do you want to share images of your workspace, hackspace, or “circuit cellar” with the world? Click here to email us your images and workspace info.

Fast Quad IF DAC

ADI AD9144 16-bit 2.8 GSPS DAC - Fastest Quad IF DAC - High DynaThe AD9144 is a four-channel, 16-bit, 2.8-GSPS DAC that supports high data rates and ultra-wide signal bandwidth to enable wideband and multiband wireless applications. The DAC features 82-dBc spurious-free dynamic range (SFDR) and a 2.8-GSPS maximum sample rate, which permits multicarrier generation up to the Nyquist frequency.

With –164-dBm/Hz noise spectral density, the AD9144 enables higher dynamic range transmitters to be built. Its low SFDR and distortion design techniques provide high-quality synthesis of wideband signals from baseband to high intermediate frequencies. The DAC features a JESD204B eight-lane interface and low inherent latency of fewer than two DAC clock cycles. This simplifies hardware and software system design while permitting multichip synchronization.

The combination of programmable interpolation rate, high sample rates, and low power at 1.5 W provides flexibility when choosing DAC output frequencies. This is especially helpful in meeting four- to six-carrier Global System for Mobile Communications (GSM) transmission specifications and other communications standards. For six-carrier GSM intermodulation distortion (IMD), the AD9144 operates at 77 dBc at 75-MHz IF. Operating with the on-chip phase-locked loop (PLL) at a 30-MHz DAC output frequency, the AD9144 delivers a 76-dB adjacent-channel leakage ratio (ACLR) for four-carrier Wideband Code Division Multiple Access (WCDMA) applications.

The AD9144 includes integrated interpolation filters with selectable interpolation factors. The dual DAC data interface supports word and byte load, enabling users to reduce input pins on lower data rates to save board space, power, and cost.

The DAC is supported by an evaluation board with an FPGA Mezzanine Card (FMC) connector, software, tools, a SPI controller, and reference designs. Analog Devices’s VisualAnalog software package combines a powerful set of simulation and data analysis tools with a user-friendly graphical interface that enables users to customize their input signal and data analysis.

The AD9144BCPZ DAC costs $80. The AD9144-EBZ and AD9144-FMC-EBZ FMC evaluation boards cost $495.

Analog Devices, Inc.
www.analog.com

SMD Stencil Reflow Soldering Tutorial

Surface-mount SMD reflow soldering doesn’t have to be difficult. All you need is a solder paste stencil, a hot air gun, and a little know-how. No reflow oven necessary!

Dave Jones, of EEVblog.com, covers everything you need to know in the following easy-to-understand SMD stencil reflow soldering tutorial.

The kit is available via Elektor’s partner, Eurocircuits.

The Eurocircuits kit includes all the essential SMT components, circuit boards, and solder stencils.

For SMT info and additional projects, refer to Vincent Himpe’s book, Mastering Surface Mount Technology (Elektor).

CircuitCellar.com is an Elektor International Media website.

RL78 Challenge Winner’s Workspace in Lewisville, TX

Lewisville, TX-based electrical engineer Michael Hamilton has been a busy man. During the past 10 years, he created two companies: A&D Technologies, which supplies wireless temperature and humidity controllers, and Point & Track, which provides data-gathering apps and other business intelligence tools. And in his spare time, he designed a cloud electrofusion machine for welding 0.5″ to 2″ polyethylene fittings. It  won Second Prize in the 2012 Renesas RL78 Green Energy Challenge.

In an interview slated for publication in Circuit Cellar 273 (April 2013), Hamilton describes some of his projects, shares details about his first microcontroller design, and more.

Michael Hamilton in his workspace. Check out the CNC machine and 3-D printer.

During the interview process, he also provided a details about his workspace, in which he has a variety of interesting tools ranging from a CNC machine to a MakerBot 3-D printer. Hamilton said:

I have a three-axis CNC machine and MakerBot 3-D printer. I use the CNC machine to cut out enclosures and the 3-D printer to create bezels for LCDs and also to create 3-D prototypes. These machines are extremely useful if you need to make any precise cuts or if you want to create 3-D models of future products.

Hamilton also noted:

I recently purchased a Rigol Technologies DSA-815-TG spectrum analyzer. This device is a must-have, right behind the oscilloscope. It enables you to see all the noise/interference present in a PCB design and also test it for EMI issues.

Michael Hamilton’s test bench and DSA815

He has a completely separate area for PCB work.

A separate space for PCB projects

Overall, this is an excellent setup. Hamilton clearly has a nice collection must-have EE tools and test equipment, as well as a handy CNC machine and decent desktop storage system. The separate PCB bench is a great feature that helps keep the space orderly and clean.

As for the 3-D printer, well, it’s awesome.

Electrical Engineering Tools & Preparation (CC 25th Anniversary Issue Preview)

Electrical engineering is frequently about solving problems. Success requires a smart plan of action and the proper tools. But as all designers know, getting started can be difficult. We’re here to help.

You don’t have to procrastinate or spend a fortune on tools to start building your own electronic circuits. As engineer/columnist Jeff Bachiochi has proved countless times during the past 25 years,  there are hardware and software tools that fit any budget. In Circuit Cellar‘s 25th Anniversary issue, he offers some handy tips on building a tool set for successful electrical engineering. Bachiochi writes:

In this essay, I’ll cover the “build” portion of the design process. For instance, I’ll detail various tips for prototyping, circuit wiring, enclosure preparation, and more. I’ll also describe several of the most useful parts and tools (e.g., protoboards, scopes, and design software) for working on successful electronic design projects. When you’re finished with this essay, you’ll be well on your way to completing a successful electronic design project.

The Prototyping Process

Prototyping is an essential part of engineering. Whether you’re working on a complicated embedded system or a simple blinking LED project, building a prototype can save you a lot of time, money, and hassle in the long run. You can choose one of three basic styles of prototyping: solderless breadboard, perfboard, and manufactured PCB. Your project goals, your schedule, and your circuit’s complexity are variables that will influence your choice. (I am not including styles like flying leads and wire-wrapping.)

Prototyping Tools

The building phase of a design might include wiring up your circuit design and altering an enclosure to provide access to any I/O on the PCB. Let’s begin with some tools that you will need for circuit prototyping.

The nearby photo shows a variety of small tools that I use when wiring a perfboard or assembling a manufactured PCB. The needle-nose pliers/cutter is the most useful.

These are my smallest hand tools. With them I can poke, pinch, bend, cut, smooth, clean, and trim parts, boards, and enclosures. I can use the set of special driver tips to open almost any product that uses security screws.

Don’t skimp on this; a good pair will last many years. …

Once everything seems to be in order, you can fill up the sockets. You might need to provide some stimulus if you are building something like a filter. A small waveform generator is great for this. There are even a few hand probes that will provide outputs that can stimulate your circuitry. An oscilloscope might be the first “big ticket” item in which you invest. There are some inexpensive digital scope front ends that use an app running on a PC for display and control, but I suggest a basic analog scope (20 MHz) if you can swing it (starting at less than $500).

If the circuit doesn’t perform the expected task, you should give the wiring job a quick once over. Look to see if something is missing, such as an unconnected or misconnected wire. If you don’t find something obvious, perform a complete continuity check of all the components and their connections using an ohmmeter.

I use a few different meters. One has a transistor checker. Another has a high-current probe. For years I used a small battery-powered hand drill before purchasing the Dremel and drill press. The tweezers are actually an SMT parts measurer. Many are unmarked and impossible to identify without using this device (and the magnifier).

It usually will be a stupid mistake. To do a complete troubleshooting job, you’ll need to know how the circuit is supposed to work. Without that knowledge, you can’t be expected to know where to look and what to look for.

Make a Label

You’ll likely want to label your design… Once printed, you can protect a label by carefully covering it with a single strip of packing tape.

The label for this project came straight off a printer. Using circuit-mount parts made assembling the design a breeze.

A more expensive alternative is to use a laminating machine that puts your label between two thin plastic sheets. There are a number of ways to attach your label to an enclosure. Double-sided tape and spray adhesive (available at craft stores) are viable options.”

Ready to start innovating? There’s no time like now to begin your adventure.

Check out the upcoming anniversary issue for Bachiochi’s complete essay.