The other day I made a mobile device camera sled for usability testing (we are conducting tests this week). I’ve been asked via Twitter to give details about it’s construction, so here goes…

Materials required:

Aluminum flat bar - 1” x 1/8” x 8’

Microsoft Lifecam vx-1000 - Cheap and works well but you can try other options

Cable (zip) ties

3/4in Velcro

Tools required:
Hack saw (the aluminum is soft, doesn’t need to be a special blade)

Miter box - gives a straighter cut

Electric drill (with approx. 1/8in bit)

File (medium tooth) example

File (fine tooth)

Not required but nice:
Steel wool (polish out the odd scratches here and there)

How I made it:
I didn’t set out to use aluminum. I had seen a few images online where folks had used Plexiglas (aka perspex) or cardboard. I ruled out cardboard immediately; that process required gluing sheets together, pre-establishing a curve, and lots of drying time. Well, I didn’t know what the best curve would be, and I didn’t have the time to let it dry… So, plexiglas maybe?

Plexiglas comes in big expensive sheets, looked like a pain to cut, and the process called for a heat gun to create the bends. The whole idea of a camera sled was only a “nice to have”, so I wasn’t going to go to this expense to potentially fail - the testing was going on at 9:30am in the morning, and it was already 7pm. So I wandered around the hardware store looking for an alternate solution…

Aluminum! So the hardware store has aluminum strips (they call them bars) I looked at my options, and 1” x 1/8” x 8’ looked like it might work… the whole 8ft piece seemed very light, so I knew I was on the right track.

I took the aluminum home and grabbed my old webcam and my laptop - Figured out the distance needed from the camera to device (phone in this case) - “hack sawed” off what was roughly a 13” to 14” piece of aluminum and started bending. I used the corner of a wooden bench to bend it, found it moderately easy (not too easy) and made sure that each bend wasn’t twisting to the left or right. I could see that my bends could not be changed without applying MUCH more force than the sled would receive under normal use - cool!

The next part was to clean up the edges. I used a moderately rough hand file, then went back over with finer files - Wouldn’t want the user to get scratched with the sled. (I also buffed it with steel wool to make it look better, but that’s just me)

Next I disassembled the webcam’s base and found that the body of the camera was made to go into about an 1/8th inch hole. I drilled an 1/8th hole in the aluminum, and attached the camera. I used a plastic washer that I made on the spot (we now have one piece of Tupperware without a lid), and used the camera’s original screw to fasten it down. Lastly, I used 2 small cable-ties to attach the cord to the aluminum, which also helps stabilize the camera, and applied Velcro to the section that makes contact with the phone (best to put the soft side on the phone back).

Done!

Everything else is software.

So far we’ve used it for five 90 minute sessions, and its working perfectly. We are asking the users if the sled bothers them and the answer has been “no” consistently - cool!

This is my solution. its really light, and requires no special tools or much more than an hour or two to make. I’m not saying its the best solution - I’m sure other materials have their benefits and I may try them in the future. This just met our specific need in a timely manner.

I hope this is helpful to your usability testing. Good luck!

Putting it to use in the lab:

Pic taken thru the observation window

Projection of the cam in our observation room

This is pretty much my first ‘blog’ ever. I might post more related things in the future… I can be found on Twitter @gwdesign