A Workspace Where Meccano Meets Arduino

Peeking into someone’s workspace gives you a glimpse of their interests, personality, and aspirations. Thus, in the same way no two personalities are exactly same, no two workspaces are identical. Some workspaces are retreat-like locations where designers spend their precious “alone time”; other spaces are 24/7 where innovators work, play, eat, and even sleep. Some spaces are intended for leisurely designing, learning, programming, and tinkering. Other spaces are high-pressure work zones where electronics innovators endeavor around the clock to create the systems and programs that pay their bills. And so it’s due to the personal nature of each workspace that we’re grateful to the generous innovators who’ve pulled back the curtains to give us a look.

Today let’s check out a space that’s intended more for innovation and learning than building the next money-making embedded system.

Ralph Laughton’s multifunctional London-based workspace was designed for model-making and Meccano-building. It wasn’t intended to be an electrical engineering workspace.

But Circuit Cellar and Elektor members shouldn’t overlook a space simply because it isn’t full of MCUs, soldering irons, PCBs, and EE test equipment. You can learn a lot by studying someone’s work area: innovative storage systems, novel workbench designs, handy power supply solutions, equipment customization, and more.

Laughton's bench in London

Laughton wrote the following with his submission:

Please find attached a photograph of my modest workspace here in my workshop in London, England. My space has to be shared with other activities such as model making as in this picture. Component storage and larger equipment is stored to one side of the bench, keeping the main area clear. The shelves across the window are mounted on adjustable brackets. Not only does this give flexibility, but it enables easy access to the window and blind for cleaning and maintenance.

On his blog he writes:

My workshop has to accommodate woodworking, model making, photography as well as anything else that needs fixing, modifying or investigating.

When comes to investigating, Laughton has begun learning about Arduino. In late April he posted the following about his early experiences with it:

I am now at the stage where I can make it do what it is supposed to do and I have even written and modified my own lump of code. This may not seem like much to some of you reading this but for me this is a big leap into the world of digital electronics and microprocessors—something I didn’t think I would ever entertain. Mind you, what do I know? I used to think digital photography would never catch on.

So, with Arduino and the recent purchase of a scope (see his May 2 post), Laughton is positioning himself to take on more electronics projects in his multifuctional workspace

We can’t wait to see what sorts of Arduino-controlled Meccano projects he creates.

Do you want to share photos of your personal electronics workspace, hackspace, or “circuit cellar”? Do you have an article or tutorial you’d Circuit Cellar to consider for publication? Click here to submit your proposal or write-up and photos. Write “Submission” or “Proposal” in the subject line of your email.

MCU-Based “PHOTO-PAL” Camera Controller

A while back, I designed a camera and flash control device that will be the subject of a future Circuit Cellar magazine article.  This device, which I affectionately call Photo-Pal, allows me to use sound (or a contact closure) to trigger a high-speed electronic flash after a user specified delay. The device consists of a microphone amplifier, a Microchip Technology PIC16F873A microcontroller, a 2 × 16 character LCD, and six pushbuttons for the user interface. Delay from sound trigger input to flash trigger output can be adjusted from 1 to 59,999 ms.

The Photo-Pal design (Source: R. Lord)

The high-speed photos are taken in complete darkness with the flash as the only light source for the photo.  The Photo-Pal device also controls the camera shutter. Once the room lights have been turned off, an “arm” push button input causes Photo-Pal to remotely press the camera shutter button, causing the camera shutter to open. The sound trigger input is also enabled. The triggering sound then starts a delay countdown, which then triggers the flash output. Once the flash has fired, the Photo-Pal then releases the camera shutter. 

For the last several months, I have been experimenting with using Photo-Pal to freeze the action of a light bulb being shattered by a hammer, water droplets rebounding from a surface, and eggs being shattered by a pellet from a BB gun.

The BB gun timing setup (Source: R. Lord)

 

For the photos using the BB gun to smash an egg, I needed to make a cradle to hold the gun so that each shot would be aimed at the same location. I also needed to establish how long it took for the pellet to reach the egg.

An egg hit by a BB (Source: R. Lord)

To make the measurement, I bolted three sheets of plastic together and drilled a large “target” hole. I then sandwiched two sheets of aluminum foil between the three sheets of plastic so that the two foil layers were separated. The microphone for the Photo-Pal was attached to the cradle so that it would be triggered when the BB gun was fired. My oscilloscope was triggered by the Photo-Pal flash output with delay set at 0, and the interval was measured between the time of the trigger output and the moment when the two sheets of aluminum foil were shorted together by the pellet passing through them. With the target set 4 feet from the muzzle of the BB gun, this time interval was measured to be 25 ms. For the egg photographs, I added another 20 ms to the delay so that the flash would catch the egg in mid-burst, after it had started to fly apart. The 45-ms delay was then programmed into Photo-Pal for the photos.

Egg smashed and sound-triggered flash (Source: R. Lord)

 

The Photo-Pal device has several other modes of operation where it can produce a burst of flash outputs for a stroboscopic effect, or can activate the camera’s shutter from sound or at periodic intervals for time lapse photographs. As you can see, the Photo-Pal device is a useful photography tool that also can be a lot of fun to play with.

Richard Lord holds a B.S. in Electrical Engineering and an M.S. in Biomedical Engineering. During his career, he has designed digital electronics for an aerospace company and several telecommunication test equipment manufacturers. Working as a consultant in the 1980s, Richard designed several medical pulmonary test instruments and the electronics for an autonomous underwater robot. His 2011 article “Panning Control: A Digital Indexing Panoramic Tripod Head” appeared in Circuit Cellar 248.

Editor’s note: Do you have an article or tutorial you’d Circuit Cellar to consider for publication? Do you want to share photos of your personal electronics workspace, hackspace, or “circuit cellar”? Click here to submit your proposal. Write “Submission” or “Proposal” in the subject line of your email.

EE’s Two-Bench Workspace in Silicon Valley

I met Vincent Himpe—a Senior Staff Engineer at STMicroelectronics—a few years ago at the Emebdded Systems Conference in San Jose, CA. It took all of about 5 minutes to learn that he was an engineer with a lot on his mind. Himpe described his work on hard disk drives, sketched a few circuits on a piece of paper, and even mentioned a few ideas for books. (Yes, that’s books—plural.) Where does such a productive engineer get so many ideas and all that energy? I wondered after we parted. I didn’t get to ask him before the conference ended.

Fortunately, Himpe recently contacted me, so I took the opportunity to get more insight into the life of such a multitalented engineer. I sent him a few questions via email, and he kindly replied. We have some insight into where he does a lot of creating, problem solving, programming, and writing.

When Himpe isn’t working on advanced controller devices for hard disk drives at STMicro, he’s writing books (check out Mastering the I2C Bus, Elektor 2011), tackling personal design projects, and repairing surplus electronic electronic equipment in two-bench workspace in San Jose.

My short interview with Himpe appears after the following two photos of his San Jose-based workspace.

Vincent Himpe’s workbench for hardware development

Himpe’s workbench for programming

C. J.: What are you working these days?

VINCENT: I make the reference designs and the development system for a hard disk mechatronic interface chip. This chip spins the 3 phase motor, does the head positioning including velocity control for the seek algorithms, shock sensing (to park the heads when freefall or shock is detected), provides power to all other parts (it’s got 4 switching regulators onboard). In case of unexpected power loss, we protect the data by retracting the heads. We recycle the mechanical energy in the spinning platters by using the motor as generator. This gives us a few seconds of power where we can gracefully shutdown the drive, preventing disasters.

C. J.: What sorts of projects do you work on at these two workstations? Work-related projects? Personal projects?

VINCENT: Personal projects. I have a number of books published through Elektor. Some of the hardware for those was developed there.

C. J.: Can you tell us a bit about the equipment at your hardware workstation? What do you use most frequently?

VINCENT: This is almost all salvaged equipment that was half functioning or broken. Some machines were repaired by combining two broken ones. I scout local surplus stores and eBay for damaged equipment. And once in a while you get lucky. There was a local company moving to a new building. They had ceased hardware development a couple of years ago and only do IP blocks now. They had a “yard sale.” That’s where I picked up my logic analyzer and my favorite scope: an Agilent mso7104: 4 analog and 16 digital channels 1GHz bandwidth with deep memory and all the protocols enabled.

C. J.: It looks like you’re working on something at the hardware bench. On the shelf is some equipment with red wires.

VINCENT: Those are three bench power supplies e3410 from Agilent. Next to it are three 34401 multimeters, also Agilent. I’m a bit of an Agilent fan. The fact that you can easily get full-service manuals that include schematics, calibration and troubleshooting procedures makes it ideal to fix these machines. That’s not the case with many other brands. Plus, they are built to last.

C. J.: What’s the piece of equipment directly under the magnifier/lamp?

VINCENT: Looks like a roll of desoldering wick. I was working on the ringlight. You can see a circular PCB just above it. Thirty-six white LEDs driven by a current-controlled boost pump with PWM. The halogen light bulbs in my Mantis burn out too easily. So I will replace them with this ringlight.

C. J.: How many solder stations do you have at your hardware station?

VINCENT: About seven. I have a Microtouch for precision work, SMD tweezers to remove passives, a hot air pencil, two WSP80s with different tips (so I don’t have to switch tip continuously while working), and a regular desoldering station with a vacuum pump. These are all surplus and/or repaired machines.

C. J.: What is board you’re working with at your software station?

VINCENT: That is a controller board for a UV exposure unit to make PCBs. It’s got an ATmega328 and LCD display. The board does double duty as pizza oven reflow controller. Just install two thermocouple interface chips and change software.

CircuitCellar.com is an Elektor International Media (EIM) publication. EIM published Himpe’s book, Mastering the I2C Bus.

Propeller Games (P1): Hi Lo

Welcome to the Propeller Games! In a few installments, I’ll present several gaming projects that use the Parallax Propeller chip. The Propeller is perfect for gaming with its multiple CPU cores to handle simultaneous gaming activities and its on-board video generation circuitry.

My first game project is the classic “higher/lower” game, where the computer thinks of a number between 0 and 99 and you guess it. You have probably seen this played as the “Clock Game” on The Price is Right TV show, though some contestants struggle with a basic binary search algorithm. (You can watch videos of the game at YouTube.com.)

This entire project is built on a solderless breadboard. If you are new to the Propeller, this is the perfect project to get acquainted with the hardware and programming. If you are a Propeller guru, you will enjoy the nostalgia of gaming on LEDs and push buttons. Grab your breadboard and follow along.

Parts

What you’ll need:

  • Breadboard and wire
  • 9-VDC wall transformer
  • Parallax PropStick USB
  • Two-digit 7-segment LED display
  • Five SPST pushbuttons
  • Audio speaker
  • Sixteen 200-Ω resistors
  • Five 10-kΩ resistors

The board and basic parts

The Parallax Propeller chip requires a few external components. You need a 3.3-VDC power regulator, a crystal, and a USB-to-serial converter. You also need a serial EEPROM if you want the Propeller to run your program at power up. You can buy all these separately and wire them up on the breadboard. Or you can save time and space with the Parallax PropStick USB. It combines all these external parts on the same footprint as the 40-pin Propeller chip.

I bought the LED display for this project from Mouser Electronics (part number 630-HDSP-521E). The large red segments are common anode (common ground). You supply positive voltage from a propeller port pin through a 220-Ω resistor to light the segments.

I bought the push buttons from Pololu Robotics & Electronics (part number 1400). They are specially designed for mounting on a breadboard. One side of each switch is connected to 3.3 V and the other is connected to a propeller port pin and pulled to ground with a 10-kΩ resistor.

I bought the speaker from Digi-Key (part number 668-1140-ND). The negative terminal of the speaker hooks to the breadboard’s ground. The positive terminal hooks directly to a Propeller port pin.

A speaker, one LED segment, and one switch wired to the Propeller

I placed four of the switches on the corners of the display. These switches are used as up/down inputs for each digit allowing the player to select a number from 00 to 99. The fifth button to the right of the display is the “Enter” button.

The photo above shows the speaker, one LED segment, and one switch wired to the Propeller. I tested the hardware and software incrementally as I hooked it up instead of trying to debug the final system as a whole.

The Parallax Propeller Tool is the free graphical Integrated Development Environment (IDE) you use to develop code for the Propeller. The code editor colors and highlights your work making it easy to see functions and keywords. It also manages indentation. The SPIN programming language uses indentation to identify code blocks much as Python does.

Basic hardware test

The code above is my basic hardware test. The CON (constants) section at the top configures the clock speed of the chip: 5 MHz × 16 = 80 MHz. The OBJ (object) section pulls in the serial terminal driver library. This library object allows you to use the USB cable for both programming and an input/output terminal. The one second pause on line 12 gives you time to switch from the IDE program to the terminal program on your PC once the code is downloaded. The Propeller tool download includes the parallax serial terminal for your PC.

Line 10 sets general I/O pin 0 (P0) as an output (they are inputs by default). Line 17 reads the switch connected to P11 and turns the LED segment on or off accordingly. Line 18 prints the state of the input pins to the PC terminal in an infinite loop.

Parallax serial terminal

It took me a while to warm up to the SPIN programming language. It is syntactically very different from C and its derivatives. But conceptually it is familiar: you break your software up into functions and local/global variables. In the end the simplicity of the syntax and the friendliness of the IDE won me over!

I really like the “Propeller font” used in the Propeller Tool IDE. It includes special symbols you can use to draw circuits and timing diagrams in your code comments. For instance:

Check out the font

Now to wire up the rest of the LEDs and switches. I thought about wiring the left digit to the first port byte and the right digit to the second port byte so that the segments are laid out the same way in each byte. This would make the software easier to write. But the pins for the segments on the display are kind of scattered around at random. The wiring is easier and neater if you wire the segments from the bottom of the display to the bottom of the propeller and from the top of the display to the top of the propeller. You can make up for the scattered pattern with software.

Two tips: Wire the segments from the bottom of the display to the bottom of the Propeller. Wire from the top of the display to the top of the Propeller.

Hi/Lo breadboard layout

That’s it for this installment. Now I’ll clean up all the little wire stripping sprinkles I left around my workbench. In Part 2 of this series, I’ll switch modes from hardware to software and write the Hi/Lo game. Hopefully you are following along. Until next time, may the COGs be ever in your favor.

Chris Cantrell earned an MSEE from the University of Alabama. He writes Java and Flex for Emerson Network Power in Huntsville, Alabama. Circuit Cellar published 10 of his articles between 2002 and 2012: Issue 145, Issue 152, Issue 161, Issue 184, Issue 187, Issue 193, Issue 205, Issue 209, Issue 139, and Issue 260.

One Electronics Workspace Among Nuremberg’s Thousands

Living in and around the international technology hub of Nuremberg, Germary, are tens of thousands of professional electrical engineers, tech-focused academics, and electronics DIYers. According to the city’s website, the IT sector—comprising radio technologies, embedded systems, and software development—has more than 100,000 employees working in more than 7,000 companies.

Heiner Tucher's bright, sufficiently powered electronics workspace

Within this burgeoning city and metro area are innovative circuit cellars, hack spaces, and workspaces of all sorts. Let’s take a look Heiner Tucher’s space.

With a general interest in electronics, Tucher built the space to serve as his “personal hobby room.” He works with older parts, and builds some of them himself. The tube-based generator is still full functional, he said.

If you look closely, you’ll see Tucher smartly equipped his workbench with a few essentials that every serious electronics designer should consider for his or her space:

  • Sufficient power: It’s no secret that easily accessible, wall-mounted power strips make designers’ lives much easier. Tucher has a great power supply setup.
  • Smart Storage: The process of designing and programming an electronic system comes with plenty of obstacles and bugs. So why create more headaches for yourself by cluttering your space or mixing random parts in unlabelled boxes and drawers? A storage system doesn’t have to be expensive or elaborate. Tucher made good use of what look like basic cabinets with decent depth. Nice and simple, yet extremely useful.
  • Proper lighting: Check out the overhead lamp Tucher placed suffificently above the main work bench. Notice how you don’t see any shadows from his various pieces of equipment. That’s essential when working with small components.

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.