By Tyler Moskowite, engineering intern

One of my all-time favorite projects to build has to be the Yagi Antenna from Make: Volume 24. The Yagi Antenna tunes into satellites orbiting the Earth and listens to their transmissions. I am still fascinated with the simplicity of the project. Besides the UHF FM radio, the materials required for the build are easy to find and inexpensive. In under two hours you will be able to tune in to the signals from space. Anyone who has the slightest interest in space, radio, or even spying should consider building this project. The most time-consuming part of this project is waiting for satellites to appear.

In my opinion the most important part of this entire project is patience. There are only a few operational satellites that radio operators use on a daily basis, and even then transmissions can be scarce or short. I had the most success with the following satellites: AO-ECHO, SAUDISAT 1C, and the HO-68. Make sure you get the latest information available on these satellites by going to their official web page.

For this build I was using the Uniden BC72XLT hand-held scanner, as seen in the materials list from the magazine. I initially had issues listening in on the satellite transmissions due to the Doppler effect. The Doppler effect changed the frequency of the signal just enough to distort the incoming message so that all I heard was static noise. Luckily the Uniden BC72XLT has a wonderful feature which allows you to set it to scan a range of frequencies. This feature compensates for the minimal frequency distortion, so there is less static when listening to the message. Although it may require a bit of tinkering around with the instruction manual to get this to work for you, it's worth the effort and time.

Finding the exact location of satellites and how they rise and fall in the sky can be a bit tricky. The article recommends you start with Heavens-Above site for finding satellite orbital paths, but I have found that the times provided by this website might not always be right. Make sure you know the direction that the satellites orbits when you are aiming your antenna. The first time I tried to listen in on a satellite I had been starting at the wrong side of the horizon, which is why the transmissions were so short. You can reference the direction via Heavens-Above, and move the antenna to track the movement of the satellite and pick up more of the transmitted signal.

Be sure to note the angle that the satellites rise to, and the time that it is expected to pass your location. You will be able to pick up a better signal if the satellites are traveling at higher relative altitudes; however, the majority of the satellites orbit at lower angles and produce mediocre results. At most there are only five high-angle passing satellites per day, so timing will be important. Take some of my failures into account, and go out and have some success in your first amateur satellite listening adventure.

Check out MAKE Volume 24:

MAKE blasts into orbit and beyond with our DIY SPACE issue. Put your own satellite in orbit, launch a stratosphere balloon probe, and analyze galaxies for $20 with an easy spectrograph! We talk to the rocket mavericks reinventing the space industry, and renegade NASA hackers making smartphone robots and Lego satellites. This, plus a full payload of other cool DIY projects, from a helium-balloon camera that's better than Google Earth, to an electromagnetic levitator that shoots aluminum rings, and much more. MAKE Volume 24, on sale now.

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Part 1. Setting up a background for your project.

By Ed Troxell, photo intern

As a DIYer, you share your projects to show off your expertise and to help others find theirs. But building a project and writing the steps is only half the battle. The other half is capturing images of your work that clearly show what you're talking about and what you've done in your steps.

As the photo intern for MAKE, I shoot lots of projects for the magazine and website. Here are my steps for setting up a background for photographing your project clearly to show it off in its entirety.

1. Set up your project and mini studio.
Find a well-lit area that's clear of visual distractions and provides you with enough room for shooting. If you're shooting on a workbench, clear off all the clutter and if necessary, drop a bedsheet or paper backdrop to hide everything that's not your project. The camera doesn't want to see your mess, it just wants to see your masterpiece. Extraneous items on the bench or in the background will only confuse the viewer and make a good project look bad. Clean up before you shoot.

Clean bench good (but what's that junk in the corner?):

Cluttered bench bad:


2. Know your "light temperature."
Light temperature means the color of your light, and it affects your "white balance." Most cameras react best to daylight, which is a bluish light, and I strongly recommend shooting in daylight. Shooting your project near a big window (with no direct sunbeams coming through) is a good place to start. Shooting outside in smooth shade is good option too (but not in speckled tree shadows).

Your flash is daylight balanced, so you can use your flash as a "fill" or secondary light to fill shadows. (Your flash should never be the main source of light, unless you're using a real strobe system.) Also, most of those compact fluorescent light bulbs are close to daylight balanced. They can be a nice fill too.

Just be careful not to mix the color of your lights. The white balance on your camera will get confused if warmer light is in the room (like a normal household tungsten filament light bulb), conflicting with the daylight or CF lights. Choose the light temperature you're shooting with, and stick to it.

3. Choose a clean background.
Use a plain, simple background, nothing too distracting. You want clean backgrounds that show off your work. Pick colors that go with your project or make it stand out. We tend to use bright colors. We recommend not using red, as red is a very difficult color for digital cameras. Do not use black. White is fine.

Instead of a distracting background pattern like this:

Use a clean background color like these:

4. Place your project on a level and straight surface.
Here's the photo booth we use here in the Make: Labs for shooting indoor shots, when we're not shooting on the workbench:

5. Test your settings.
Take a few shots, then check the images on your computer (ideally in Photoshop) just to check focus, brightness, file size, grain (ISO), and other details. Sometimes a setting can be off. It's best to know now, rather than find out when you're done shooting.

For example, if you're submitting projects for MAKE magazine or Make: Online, you'll need to take high-resolution photos at an aspect ratio of 4:3. High resolution means they can be printed on paper at 300dpi. (Yes, even web photos -- because we might want to print them later.)

In my next post: Shooting your project in high resolution.

By Meara O'Reilly, projects intern

I've been working on winding coils and testing out a cool new electromagnetic guitar pickup for the upcoming issue of MAKE, so I thought I'd share a modification I did a while ago on the old piezoelectric pickup that was featured on the quick and easy Cigar Box Guitar in MAKE Volume 04.

Here's the piezo buzzer used for a pickup in MAKE's original Cigar Box Guitar, still encased in black plastic.

Piezoelectric transducer discs often come in protective plastic casings, but they're actually much more sensitive without them! I've spent many an hour with needlenose pliers cracking them open like steamed lobsters to get at the ceramic and metal underneath, and I've found the difference in amplification to be definitely worth it.

The original design had the plastic-encased piezo element (a piezo buzzer) inside the cigar box, and it worked fine, but I've learned that it works even better without the plastic case.

One of our old CBGs even had the piezo buzzer mounted directly under the strings, sort of propping them up into alignment with the fretboard, in order to show off the pickup. This was failing for two reasons: first, the point of contact was too broad, causing a buzzing sound as the strings hit the long, flat surface of the plastic, and second, because the piezo disc was oriented at the bottom of the plastic casing, it was protected from some of the most important vibrating bodies on the guitar -- the strings!

I decided to build something where a narrower contact point (or bridge) could directly conduct the vibration from the strings to the disc.

Here's my modified piezo pickup, naked, in direct contact with the bridge, and sounding great.

I cut a small block of balsa wood (about the width of the fretboard and long enough for the disc to rest comfortably upon) to prop up the whole setup. I placed placed the piezo on top of this balsa base, then cut a small piece of a wooden barbeque skewer we had lying around and placed that on top of the piezo as a bridge.

The strings, once wound on, will normally hold the bridge in place (in fact, many types of acoustic guitars have some sort of free-standing bridge like this), but for extra security, I cut both of the rounded ends off a popsicle stick and glued them flush with the balsa block to provide a sort of "baby gate" for the skewer, to keep it from rolling too much.

Voilà! The smaller contact point, applied directly to the piezo disc and held in place by the strings, conveys the string sound wonderfully.

What pickup modifications have you discovered?

By Tyler Moskowite, engineering intern

I recently received my first smart phone, an iPhone 3GS, from my brother who just got back from Iraq. It has turned into my PDA, map, social networker, and a boatload of other stuff I didn't even know it was capable of doing. Let's just say simply, I love this device. Which has prompted me to want it to be on every moment of everyday, and let's be honest, the iPhone 3GS eats through battery life at a decent rate. Being a somewhat outdoors-active person, and because I enjoy the planet that I live on, I decided to build a solar charger for my iPhone 3GS.

When I started researching best way to build one of these, the simplest way was obviously to start off with a MintyBoost USB Charger Kit v2.0. Make sure to pick up the v2.0 and not v1.2, as the iPhone 3GS will not work with a v1.2 kit. This is due to the voltage on the D+ and D- pins that the iPhone 3GS uses to connect to USB. (Malaysian student Chen Tzy Wen has posted a good guide explaining how the voltage on each pin works, and the comments have good information in them as well.) Using the two 100k? resistors worked fine to charge the iPhone.

This design allows for a power source to be attached to the MintyBoost to charge your iPhone 3GS via a USB cable. Included in the kit is a 2xAA battery holder, but I wanted a more renewable and longer lasting energy source.

By Kris Magri, engineering intern

How I designed Makey, Part III: The Ping sonar rangefinder and maiden voyage

As we return to our robot design saga, making Makey the Robot for MAKE, Volume 19 ...

The actual robot is still just a prototype with 2 wheels and motors and no sensors, electronics, or brains inside. The better body exists only in the computer. Maker Faire is looming. I've been tapped to give two "Make Your Own Robot" workshops, and I reckon that having a working robot would be a very good idea.

I'm trying to get the Arduino into the robot body. Suddenly I learn a profound lesson regarding computer-aided design. In real life, circuit boards cannot morph through walls into their desired resting place. In the computer, it happens all the time. With a simple motion of the mouse, the Arduino circuit board has glided into place, right through the aluminum robot body ... but in real life, it won't fit. There is no possible angle or tilt that will get the Arduino into the robot. Out come the Vise-Grips and hacksaw. I saw, bend, and twist off the offending aluminum tabs. This is reality-aided design.

The battery pack doesn't fit because it hits the nuts and bolts that hold the motors in. It fit just fine in the computer model, since I didn't bother including the nuts and bolts. I'm ready to toss the computer out the window.

I show up at the Make: Labs with my fail robot. Our crew has been working like demons for weeks getting ready for Maker Faire -- preparing demos, packing everything under the sun, buying materials -- the lab is a madhouse. Eric, myself, and Steven are practically tripping over each other. I'm frantic to get the Arduino into the body and get the sonar sensor mounted somehow. Eric suggests double-stick tape. I refuse. Tape and glue, I assert, are for people who don't know about bolts and rivets. Eric manages to cram the Arduino in sideways. It barely fits, actually, it doesn't quite fit, it sticks up a little. When I drill a mounting hole, 1/3 of the hole isn't there. But the bolt manages to hold.

At this point I only have a vague idea of what motor will be turning Makey's "eyes" or how to fit it inside. We zoom off to the local hobby shop and pay way too much for the smallest servomotor they have in stock.

Steven offers to take on the servomotor/sonar sensor mounting problem. He's making detailed measurements and calculations, trying to figure out how much space there is and where the servomotor will fit into this 3D space without hitting the electronics. He marks everything and explains his calculations to me. I can't follow them, but it sounds good and looks like it might just fit. I drill the holes, we put the servo in, then close up the robot. It fits! There is much rejoicing.

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By Eric Chu, engineering intern

There aren't many low-budget ways to customize one's yo-yo. The most common ones are either painting or dyeing, but they're limited: paint chips off with time, and dyeing is only for plastic yo-yos.

Being a yo-yo fanatic, I regularly visit the blog yoyoskills.com for yo-yo news. There I recently read a post about spin-activated LED side caps that fit into the side of yo-yos. They're low-cost ($6) and look very cool; a perfect customizing add-on for a yo-yo. Unfortunately, they only come in one size, thus only fitting a few yo-yos.

I thought it'd be a fun project to make my own set (and it was!). I used a One Drop Project yo-yo.

How It Works
Using the centrifugal force generated by the spinning of the yo-yo, the spring, acting as the switch, is pulled outward. It makes contact with the positive leads of the LEDs, thus completing the circuit, turning the LEDs on.

It looks great in action, day or night. Check out the video:

I'll be writing up the project as a DIY article soon. Look for it in MAKE Volume 22 this spring.

By Ed Troxell, photo intern

I'm the photo intern at MAKE but I like to do more than just one thing, like starting my own magazine and shooting videos. A couple months ago I came across IdeaPaint in Inc. Magazine -- it's this cool paint that you can apply to any surface and turn it into a whiteboard. It comes in ten colors and can be used pretty much anywhere in your home, office, school, you name it, as long as the surface is smooth and flat. It's great for team meetings, kids' rooms, and brainstorming.

I sent the link over to MAKE managing editor Shawn Connally, and the next thing I know we've got a can of orange IdeaPaint on its way to the office for us to test out. We're gonna make an orangeboard!

By Meara O'Reilly, projects intern

I've been tinkering with the electronics on various cigar box guitars for a while, but I'd never had the chance to build one from the ground up. So when MAKE editor-in-chief Mark Frauenfelder wrote up a new how-to for an acoustic version of the guitar for the upcoming issue (MAKE, Volume 21, "Traditional Cigar Box Guitar"), I jumped on the chance to test-build it.

Mark Frauenfelder's new acoustic cigar box guitar in MAKE Volume 21, coming in January.

As always here in the Make: Labs, it can be quite an adventure trying to sniff out all the possible interpretations of instructions while at the same time learning new skills, and this guitar build was no exception! I made two orientation-related mistakes based on an early manuscript and had quite a time trying to finish the build. In retrospect, the misunderstandings seem silly, but once made it's really easy for mistakes like these to compound -- due to structural weakness, later on my guitar neck snapped, twice! -- so I thought I'd write about them here, even just as an ode to those mistakes you think you'd never make, but somehow end up making anyway:

By Steven Lemos, engineering intern

Making the Hydrogen-Oxygen Bottle Rocket (that Adam Savage is posing with on the cover of the new MAKE, Volume 20) was a pretty basic endeavor, with the exception of the circuit. The original schematic diagram had a flaw in it, but only after we breadboarded the circuit -- twice -- did we catch it.

I guess that's the reason we MAKE interns build the projects that run in the magazine, so it's us who bang our heads against the table and not you. I will kindly take that cookie now.

The experience showed me that, sure, when working with electronics it's easy to misplace a component or wire, or completely miss something, which I already knew, but it's just as easy to have a diagram be the culprit. So a word to the wise (a word I'm sure all the experienced hobbyists have already discovered for themselves): if you take care when putting together these tedious circuits it will pay off, for if you can trust in your work, then you'll know the culprit lies in the plans, and you won't spend hours chasing that metaphorical wild goose.

Twice we breadboarded this bad boy before discovering an error in the schematic -- so you won''t have to.

But on to the actual launch. :) We had talked to the local electronics store owner, who at the time was making his own hydrogen using a more sophisticated apparatus, and who was interested in what we were doing with ours. So he came to watch, and brought along his professional pyrotechnician friend, who showed us how to make fuses with 12V and tiny resistors (basically the resistors pass so much current that the wire heats up and can act as a fuse to light stuff -- voilà, cheap fuses).

Our beautiful 2-stage HHO rocket ready for test launching -- before being crippled by a crash.

The first launch was a success, with the two stages going off rather quickly in succession, so we dialed in a little more delay time in the circuit before the stage 2 ignition. This was good and bad. We got more height out of the rocket on our second launch, but on its return it landed electronics side down. This resulted in our circuit behaving oddly.

So, not ready yet to call it a day, we began firing off only one stage at a time, adjusting the proportions of HHO (hydrogen and oxygen gases), water, and air, and testing the makeshift fuses, which worked fine for a single stage, but due to the time they take to ignite (3sec@12V) might not work for 2 stages.

We probably launched 12 times that day, attracting passersby. Good weather, new friends (who like blowing stuff up), and multiple launches. All in all, a good day. Houston, we have liftoff.

• Related: MAKE, Volume 20: "For Kids of All Ages"

By Kris Magri, engineering intern

How I designed Makey, Part II: Creating the "stretchy" robot body in Inventor

When designing Makey the Robot for MAKE, Volume 19, I ran into a problem that plagues all kinds of designers -- how to continually redesign a body to accommodate changes in whatever's crammed inside it?

Once I'd sketched out Makey's configuration and modeled the major parts in Autodesk Inventor 3D modeling software, I really got into some of Inventor's awesome features. Inventor has three basic design types you work with: sketches, parts, and assemblies. Up to this point I had designed each individual component, including Makey's robot body, as a part, as shown in Figure A.

Fig. A: Makey's sheet metal body, near-final version, shown as a single part in Autodesk Inventor. Because I designed it as a component of an assembly, all the mounting holes and dropouts are perfectly aligned to internal robot components; if I move the components, Inventor automatically moves the holes.

Once I had these parts modeled, I placed them together into an assembly, as in Figure B. Then, I attempted to stretch the robot body as needed by making that part "Adaptive" inside the assembly. (That's what Inventor calls "stretchy" parts, and it's a powerful feature.)

Fig. B: Makey's body shown as part of an assembly in Inventor, constrained to the edges of the motors (at bottom, in blue). If I move the motors, the body automatically stretches to accommodate the new motor positions. Similarly, I constrained the battery boxes (at top, in tan) to the body, so wherever the body stretches, the battery boxes follow automatically. Nice!

Also, I cut holes into the body where I needed them for mounting the motors. This was the wrong approach! It seemed to work, but when I looked at the robot body as a part, outside of the assembly, the holes I had made weren't shown. They had simply vanished.

The reason for this is that Inventor can't know ahead of time how you're going to use a part. You could design one part that could be used in multiple assemblies, so if you alter the base part in any way inside one particular assembly, the alteration exists only in the assembly, but the base part is unchanged. Thus, my changes didn't "take hold."

The key was to create the robot body from inside the assembly. You can actually be inside an assembly and make a brand-new part. To do this, in the Assembly Panel area, instead of selecting Place Component, choose Create Component.

I ended up first creating what I called a "base plate," which existed solely to help me anchor all the parts, including the robot body. It would not be a part I would actually fabricate. I then placed the base plate, the motors, the Arduino, and the batteries into an assembly, using Place Component, and assembled it all by anchoring everything to the base plate (using constraints). This was pretty much what I had been doing before.

Now, still inside the assembly, I created a new part, via Create Component, which would become the robot body. I selected the material type Sheet Metal.ipt, since it's a sheet metal part, and created each bend and flange step by step, inside the assembly. This robot body now "belonged" to the assembly, and was adaptive inside the assembly. Any editing of it, from that point on, was always initiated from within the assembly.

Instead of making the body a specific width, I just made everything extra large with no dimensions. Once the body was formed, I finished editing, and now I was back inside the assembly with my new robot body. I then constrained the side of the body to an existing "edge" from another part, for instance, the sides of the motors (Figure B). When the constraint went into effect, the sides of the body "snapped" into place next to the motors. To make holes, I projected the motor mount holes onto the robot body, again edited the robot body part (from within the assembly), cut holes there, and then the holes "stayed put," so to speak.

Success at last -- I had modeled a fully adaptive robot body that I could easily modify to accommodate all the robot components I would be cramming inside it.

Next up: The battle to fit the brains inside.

More: How I designed Makey the robot, Part I: The first design