$30 Gobo Arm: Mobile Document Camera Stand

From MAKE Magazine

From MAKE Magazine

This project first appeared on the pages of MAKE magazine.

Go hands-free for the price of a clamp.

  • Author: Adam Flaherty
  • Time required: 30 minutes
  • Difficulty: Easy
  • Add Note x
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If you’re familiar with tabletop product photography and video, you know what a pain it can be to shoot overhead shots while working on your subject. Tripods just get in the way.

The usual remedy is a document camera, the modern equivalent of the overhead projector. These cameras let you display close-up shots with an LCD projector or external monitor, and they cost between $500 and $1,500. They’re well suited to capturing images of document-sized objects, but come on, a grand for a glorified webcam?

We’ve all got streaming video on our smartphones now, so couldn’t we just use that instead? The problem is, how to hold it over the project without a tripod to bump into.

Hollywood grips solve this problem with what is known as a gobo arm, a lightweight mount that lets you position your smartphone (webcam, etc.) down where the action is without getting in the way. Commercial units run $100–$150, not including the $30 clamp you attach it to. But for the price of one of those fancy clamps, you can piece together your own Mobile Document Camera Stand using easily sourced parts.

It’s easy. If you can make cuts with a hacksaw, you can build this project. There’s also plenty of room for improvement. For example, I recently upgraded the lock washers to the “curved disc spring” type, and they work great.

Sections
Tools
Relevant parts
  • Threaded rods (3), ¼"-20, 12" long All part numbers are McMaster-Carr (mcmaster.com). MC: #98790A320, $0.58/ea
  • Setscrew terminal lugs (4), ¼", straight tongue, copper MC: #6923K62, $2.04/ea
Relevant parts (continued)
  • Spacer (2), ½" OD, .252" ID, ½", nylon MC: #94729A250, $0.68/ea
  • Wing nuts (2), ¼"-20 MC: #92001A321, $0.33/ea
  • Aluminum tubing (2), ½" OD, 0.4" ID, 10" length MC: #89965K253, $8.81/36" length
  • Clamping knob (2), threaded stud, 3-arm, ¼"-20, plastic MC: #57715K78, $1.70/ea
  • Lock washer (2), ¼", curved disc spring MC: #91113A029, $2.92/100 pack
  • Coupling nut, ¼"-20 MC: #90264A435, $0.19/ea
  • Beam clamp, ¼"-20 MC: #3044T1, $1.04/ea
  • C-clamp around $3.00
  • Smartphone camera adaptor, generic Check eBay or theglif.com (for the fancy iPhone 4 model).
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Add Note Edit Step 1 — Cut rod and tube, and assemble.  ¶ 

  • Cut two 11½" lengths and one 1¾" length of threaded rod. Cut two 10" lengths of aluminum round tube. Clean up the ends with a file.

  • Insert the threaded rod into the aluminum round tube, and use hex nuts to hold in place. Optionally, you can use nylon spacers or 8" strips of electrical tape wound around the threaded rod toward each end to position the tube. You should have enough rod left at each end to fit into the terminal lug.

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Add Note Edit Step 2  ¶ 

  • Attach a single terminal lug to one end of the first threaded rod, and tighten with a slotted screwdriver.

  • Attach terminal lugs to both ends of the second threaded rod, and tighten. Then thread the coupling nut onto the 1¾" threaded rod.

  • Attach the remaining terminal lug to the end and tighten.

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Add Note Edit Step 3 — Assemble the friction joints.  ¶ 

  • For the first friction joint, insert a nylon spacer onto the clamping knob shank. Insert the end of the terminal lug over the nylon spacer, keeping the locking screw facing away from the tip of the shank. Insert a lock washer over the terminal lug.

  • Now, insert the end of the terminal lug of the second threaded rod over the lock washer, keeping the locking screw facing toward the tip of the shank. Hold it together with a ¼"-20 wing nut.

  • Repeat for the second friction joint, to attach the 1¾" threaded rod assembly to the other terminal lug of the second 11½" threaded rod assembly.

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Add Note Edit Step 4 — Finish  ¶ 

  • Thread the beam clamp onto the remaining end of the first threaded rod assembly and attach it to the C-clamp.

  • Make sure a little extra of the threaded rod sticks through the bottom of the beam clamp. You’ll want this overhang to wedge the C-clamp into so that the beam clamp aligns straight.

  • Attach the generic smartphone tripod adapter to the ¼"-20 end of the 1¾" threaded rod assembly. Use the coupling nut to adjust for a snug fit.

  • Now you’re ready to photograph your project for sharing at makeprojects.com, or even stream live video from your workbench.

This project first appeared in MAKE Volume 27, page 126.

For more information, check out the Video Making category page.

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I believe the parts list should include 4 hex nuts

Chris Mansley, · Reply