Andy Clyce and Shiloh Barnat | July 26, 2012
2010 was “the year mobile connected the world,” and ever since, we’ve all been on fast-forward to evolve our mobile design, development and testing practices. The digital experiences we craft are increasingly used on a wide variety of devices in a wide variety of contexts. But the average task success rates for people using mobile sites and apps is still way lower compared to big screens (62 percent for mobile vs. 84 percent for desktop according to Jakob Nielsen’s Mobile Usability Update). And customer expectations of fluid digital experiences that morph to every context show no signs of turning back.
So, testing our creations in device context is NOT optional. As with the desktop environment, mobile testing often needs to be recorded so we can remember what happened, spot the pain points and communicate the opportunities that culminate in a stellar mobile experience. But by nature, mobile usage happens out in the world rather than in a controlled lab with fancy equipment, so mobile usability testing equipment must also be prepared to work out in the real world.
Thus we set about arming our customer research with portable mobile recording capabilities only to find that there really wasn’t an obvious solution. It would be great if there were some simple way to record screen activity on all sorts of handheld devices, but we’re just not there yet. And, in keeping with Lokion’s keep-it-simple usability approach (no two-way mirrors, wired mics or cameras dropping out of the ceiling), we weren’t exactly thrilled with the obtrusive out-of-the-box options on the market at the time.
So, we made our own.

We knew what we wanted:
- Flexibility to capture users’ screen activity, hands and facial expressions on their own devices in any context — i.e. lightweight, portable support for two cameras
- Unobtrusive yet stylish design allowing natural device use while representing the value of our professional services (after all, the quality of mobile usability research is way more about the skills of the team than the tools they use)
- Quality, focused video output without bloated costs or file sizes
We studied our options and learned from others publishing about their DIY mobile testing gizmos (ex: Mr Tappy sells for $289 without camera and MacGyver always finds a way). We were particularly inspired by Harry Brignull’s post about making a homemade “sled” in a day for less than $10.
Two years later, after making and using our own mobile usability testing sled, hearing feedback from our customers, a follow-up about our mobile sled from Mr. Brignull, plus growing conversations across the Web about approaches to affordable homemade mobile usability testing tools, we’d like to share details about our design as a call-to-action for further evolution.
Lokion’s mobile sled design (Let’s begin!):
Step 1: Gather supplies. Effective and affordable.
Supply list:
| Acrylic sheet, 5.6mm | http://www.ponoko.com | up to $95 per sheet (less without cutouts and engravings, makes 7 sleds) |
| 2 Web cams | http://amzn.to/NKM59l | $3-$20 each |
| Screws | http://www.mcmaster.com (search: 90190A057) | $6.45 for 1 pack of 10 |
| Washers | http://www.mcmaster.com (search: 96765A105) | $3.94 for 1 pack of 100 |
| Painters tape | http://low.es/NsoawE | $4.15 per roll |
| Rubber grip spray | http://bit.ly/OxyMIs | $5.98 per can |
|
TOTAL: |
$28-$63 per sled with cameras |
Tools (if you don’t already have them):
| 1 Heat gun | http://low.es/LOIJkT | $25 |
| Drill | http://amzn.to/S4AkNQ | $20 |
| Drill bits | http://amzn.to/MhFx0q | $5-$10 |
Step 2: Make sled template. Place order.
Create an account at www.ponoko.com and choose Make to get started. We decided to use acrylic for our sleds because it is lightweight yet durable. We played with several different thicknesses before landing on 5.6mm as the right balance for levity and sturdiness. Thicker gets in the way and thinner topples over when cameras are attached. We made some clear, but landed on bright red ‘cause… well, it’s our style.
Next design your template. Check out Ponoko’s 2D Design Rules. Then either download a blank template from Ponoko or feel free to use ours (which you can download from Thingiverse)! Our template produces 7 sleds, each with a series of 5 large holes in the neck for tucking away camera cables (they also help make the sled lighter). We experimented with various widths and shapes, but — first thought, best thought — stuck with a simple narrow rectangle.
With design template ready, log in and select your acrylic and click the “Upload your design” button top-right. After uploading your file, click the “Click here to add a material” link in the “Your 2D laser materials” box. You will be presented with a series of drop-down menus:
- “Choose a material type” — select “plastic”
- “Choose a material” — select “Acrylic — (your color)”
- Specify the thickness of the acrylic (we use 5.6mm)
- Specify the overall size of the sheet of acrylic (note: there are 3 sizes p1, p2, and p3 which must match your template; we use P3 — 790mm x 384mm).
- When you are finished, click the “Add this material” button.
Verify the recap of your selections and the price of your order. If everything looks good, click the “Make it” button on the left to place your order. In our experience, it takes about 2 weeks to receive your order.
Step 3: Assemble and customize. The fun part!
Once you have gathered all your supplies and received your order from Ponoko, you are ready to assemble your sled(s). Here’s how:
- Drill two holes: Lay one flat piece of acrylic face down on a table. Drill the first hole in the upper left corner where you will attach the camera that records the user’s face. Next, drill a hole in the center of the sled (between the top two cable holes if you’re using our template) where you will attach the camera that captures the user’s interaction with the device. (Note: We chose to manually drill our camera mount holes because we were still experimenting with camera placement. Now that we’re more certain about that, we may integrate these cuts into the Ponoko template.)

- Bend into shape: Plug in your heat gun and get ready to bend. You are going to make two bends in your sled. The first bend will make the arm that holds the camera over the device (about 110-degrees, between the top two and bottom three cable holes if you’re using our template). The second bend will make the flat shelf to hold the test device (about 100-degrees, just beneath the bottom three cable holes if you’re using our template). To make your bend, carefully run your heat gun slowly over both sides of a bend area. When the acrylic starts to get soft, it is ready to bend. You should not have to force it. If it doesn’t bend easily, keep heating. Hold the bent acrylic in place for a minute or so to allow time to re-solidify. You may have to adjust the bends some by reheating to ensure you get the right position for your cameras to be angled appropriately. Don’t forget to turn off the heat gun!

- Tape and spray: We tried several finishing touches (ex: gluing on no-slip padding) to help keep devices well positioned and settled on a thin textured spray surface. To apply your surface, first tape off the areas where you don’t want grip adhesive. Spray visible surface with a light, even coat of plastic grip spray. Let that dry for about an hour and repeat. Do this at least four times to get a good thick grippy surface so devices won’t slide around. When the last coat of spray is almost dry, SLOWLY remove the tape.
- Mount cameras: There are lots of small affordable camera options. Beware: many do not focus well on objects nearer than 40cm (16 in). We chose a simple round webcam with basic focus settings and LED lights to help when ambient lighting isn’t ideal out in the field (careful using lights as they can cause glare). To mount your cameras, first remove the round base that comes on the cameras by unscrewing the small screw in the bottom. Insert the post of the camera into the holes you drilled. It should be a snug fit. Next, get the washers and screws you ordered (the screw used in the camera base isn’t long enough) and attach the camera securely.

- Adjust and tweak: Plug it in. Give it a whirl. See how it performs. Adjust the angle of the bends as needed to get just the right camera focus and angles without getting in the way. You’ll want the sled with cameras attached to feel natural held in one hand holding a mobile device and also still be stable when sitting on a table. These angles are the advantage of using a sled rather than a tripod or document camera as they keep the device stable within camera view. It’s a bit tricky. Play with it until you’re happy.
We’ll save tips on hooking up your sled cameras to recording software (we run our recordings through Morae for real-time observation, task analysis and clip editing) for another post.
We already envision lots of improvements to our mobile sled design:
- A wider-base version for tablets and/or a tabletop version for all devices which may be more comfortable for lengthier sessions and facilitate more natural device usage movements (ex: easier switching from portrait to landscape device orientation, more complex multi-touch gestures, tilting and shaking, etc.)
- Smaller cameras with better gain/exposure/contrast/focus options (ex: ability to pan, zoom, and adjust settings from a separate observer computer)
Let us know on Thingiverse if you use our design, improve upon it or make your own. We welcome ideas, suggestions, references, resources and questions. That’s what’s so great about open-source design, right?! Let’s share and evolve so we can all create more usable, useful and adaptable digital experiences no matter what our customers are carrying in their hands.
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