Homebuilt Jib Arm with Motorized Pan and Tilt

I've always wanted to use a jib for those smooth, sweeping multi-dimensional shots that give so much life to the camera. Sure, you can rent them for not a ton of money, and sure, I probably wouldn't be using it on every show. But the challenge lie before me: to build a jib that shared the properties of pro jibs, for a fraction of the price.

Step 1: The Pan/Tilt Head
The hard part would be the pan/tilt system, for sure. This the stumbling block for every great jib design I found. How do you get the camera to move freely, smoothly, and without having be moving it with your bare hands?

I saw some cool cable-driven systems, but I knew I wanted something a little more sophisticated. I am not an engineer, and I know almost nothing about motors, gears, servos, electronics, etc. So the question for me was not "how do I build a pan/tilt system from scratch", it was "what ELSE is already out there that works just like a pan/tilt sytem that I can modify and use?"

I started by checking out any pictures and diagrams I could find on the internet of how they are generally constructed. Pretty simple: one set of motors for the pan, another set for the tilt. I say "set of motors" because each requires bidirectional movement. With AC, this requires two motors. DC motors can be reversible much easier. Then I started poking around on Ebay for "pan tilt" and such things. I think I found it on accident, but I made a breakthrough discovery.

Film and video cameras use remote pan/tilt heads, but so do security cameras. Not surprisingly, the vast majority across the internet are nice, small, compact, very modern all-in-one camera systems with built-in pan/tilt. But I happened on an older pan/tilt rig on Ebay. It was built by Pelco, who seems to have a monopoly on security cameras for a long time. What I found was the innards of a ceiling-mounted security camera system, the kind with the dark plastic bubble. Only mine was just the guts: the frame, sling and motors. The guy didn't even know if it worked. But I took a chance.

I bought it for about $90. It's a Pelco Pan Tilt Camera Mount; Model EDDD2500. It's a 24VAC system, it was ugly, and I had no way of testing it. I downloaded a manual from Pelco, and found the model of the control box. I found one on Ebay too, for about $50. Once I figured out the wiring, I could test it, and sure enough, it worked! Ultimately, I discovered one big drawback: each axis is on-off; there's no variable speed. This makes smooth shots difficult, since I can't feather the stops and starts. Still, I'm working on a solution to this.

Step 2: The Arm
Again, a little research into the pro systems helped me understand the concept: a cantilevered arm. If both top and bottom arms are fixed a the fulcrum, the camera end will stay in vertical alignment. A single arm would point the camera in whatever angle the arm was pointing. But having the two "arms" meant that it would necessarily stay in alignment.

For the short-term, I used a 2"x4". It's cheap, rigid, and readily available. Someday I'll buy a chunk of aluminum, but so far I haven't. One of the plans I found on homebuiltstabilizers.com utilized a large caster wheel (big, like 8" rubber tire type, and upside down) as the fulcrum. The wheel bearings make the fulcrum (raise/lower) effortless and smooth, and the swivel bearing does the same for swinging the arm around the Y axis. I added a U-shaped piece of metal strapping to the wheel fork with a couple of machine screws, then I drilled a hole on the top of it, centered on the arm. You'll see why in a moment.

For counterweight on the back end, I went to a used sporting goods store and bought about 30 lbs worth of small free weights, and one short bar. It's about 18" long, and all the weights slide onto it perfectly. It came with two locking hubs, and I bought two spring clamps. I drilled a hole through the end of the arm, put the bar through it, then used the locking hubs to securely center it. Then I can add weights, and use the spring clamps to hold them on. It worked perfectly, and cost about $30.

Step 3: The Camera Mount
The camera mount was a little more complex. I knew the camera mount would go beneath the arm. I bought a piece of sheet steel, bent it into a U shape, to go around the end of the arm. I drilled a hole near the bottom corner. This formed the main mounting element. I bought a couple skateboard wheel bearings off Ebay. I drilled an appropriately sized hole through the end of the arm, and countersink holes for the bearings. Then I threaded a bolt through the metal U, through a bearing, through the arm, through another bearing, through the metal and back out. I'm sure there were some washers in there as well. The whole thing spun very smoothly. Then I made another hole through the metal U near the top, exactly the same distance from between the middle of the arm and the hole in the top of the metal strapping. I added another smaller bolt through this hole, secured with nuts. The trick was keeping the metal from bending. It had to stay square. I knew that the distance from the hole in the metal strapping to the upper bolt in the metal U (while it was perfectly level) was the same as the distance from the center of the main arm fulcrum to the center of the front fulcrum. I cut a length of plastic-coated stranded wire a few inches longer, made small loops on each, and connected it to the upper bolt "axle" and the strapping hole. I adjusted the length until the metal U was perfectly level.

I used a small piece of 3/4" plywood for the camera base. I attached this to the bottom of the metal U with corner angles. I was then able to easily mount the camera mount to the bottom fo the plywood with a set of bolts and wingnuts. It makes for easy removal of the camera mount, which I've done many times now for transport, storage, etc.

Step 4: The Tripod and Mount
Even though we have several tripods of sufficient size and strength for the purpose, I decided a dedicated, lightweight tripod would be ideal. After playing a gig with my rock band, I watched the sound guy take the massive, heavy speakers off these very lightweight aluminum speaker stands. Perfect. I found a pair on Ebay for $25.

For the mount, I cut a small piece from the scrap 3/4" ply, mounting the caster wheel fulcrum to one side. I bought a galvanized tube about 10" long that just barely fit over the top of the speaker stand. I added a galvanized flange to the end and mounted the flange to the other side of the plywood scrap.

Step 5: The Control Box
I mounted the Pelco control box very, very temporarily to the back with gaffer tape and some plastic cable ties. I still haven't figured out a permanent mounting solution. I mounted eight-conductor Romex electrical wire along the length of the arm with cable ties. I used an eight-conductor tie-down block on each end so that I could unwire both devices easily. The jib was now assembled.

Step 6: Balancing and Testing
I added a small video camera (Sony PD-150). Then I added weights to the back until it was nearly balanced. I had to fine-tune the balance with various small objects, like taping a wrench to the arm at just the right spot. But once balanced, the jib moved perfectly. I added a bubble level to the plywood scrap next to the caster wheel so that I could tell if it was level. The swivel was very smooth, and the movements were fantastic. It took a lot of playing to get just the physical movement of the arm down. I'm still no expert.

The hardest part has been figuring out the pan/tilt head. It's hard to make it smooth, and since it's not yet variable speed, getting perfect results has been difficult. But I have successfully used it in some sequences, especially using long dissolves between other jib shots. The finished product looked amazing.

Changes and Hopes
I bought a potentiated joystick on Ebay. Unfortunately I don't know anything about electronics. I haven't had any luck getting the 24VAC current to vary the speed of the motors. This is disappointing, but I haven't given up yet. Also, I'm looking into replacing the motors with DC motors. I think this might let me use my new joystick. But what do I know?

I'll be posting photos, video, etc. Sorry if none of this makes sense just yet.