This is a DIY camera stabilizer in form similar to the MERLIN. I used mostly scrap or surplus materials. A piece of 1/8 inch aluminium forms the camera platform. Below that, separated by spacers, is a slotted aluminium plate to which the gimbal housing attaches, allowing front to rear balance adjustment. An aluminium torch was reconfigured to act as a handle. It's not an ideal shape for the hand, but the head allows the ball bearing of the gimbal to be held in place satisfactorily. A curved aluminium tube screwed to the camera plate holds the washers used as counterweights. The pictures here represent experiments over a period of time, and dimensions and balance configurations are different from time to time.

The dimensions of the stabilizer against a 5cm grid.

For these experiments, I have been using a Panasonic NV-GS60 camera weighing a total of 600mg (1.3lbs) with the large battery attached. The whole system weighs about 3lbs. I have positioned the gimbal some distance below the camera to maximise the inertial effect of the camera's mass. The different heights of the counterbalance weights cause unequal centrifugal forces to be experienced by the system, and can cause tilt when panning.

I have been asked about suppliers of parts. There were only a few parts or pieces of material which I bought, and here are some sources:

Universal joint:
http://www.wheelspinmodels.co.uk/
http://www.modelsport.co.uk/

Ball bearings:
Skateboard bearings, widely available on EBay. The cheapest ones are good enough.

LED torch / flashlight used as handle:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=
380079353012
(I can't guarantee this will be identical)

The stabiliser with gimbal #1

Wind coming from the front or the rear impacts on the screen, and this is difficult to compensate for. However, this is not too much of a problem, as my body shield the system from wind coming from the front or the rear.. I could never compensate for all air turbulence, but in a steady breeze, this modification is very useful.

A practical design for an aerodynamic stabilizer, placed behind the camera.

Two versions of a small vertically aligned fin positioned at the bottom counterweight. The material is 0.7mm plastic.

The orange dots indicate the principle centres of mass of the camera and the counterweights. The yellow dot indicates the centre of the mass of the stabilizer with no counterweights or camera. The green dot indicates the centre of the universal joint. The system is shown against a 5cm grid. In this setup, the camera has a mass of 500gms. The forward counterweight's mass is 170gms, and the lower weight's mass is 210gms. The remainder of the stabilizer (excluding the gimbal and handle) weighs 320gms, and its overall influence on the balance in this setup is relatively small, although not insignificant.

The masses of the camera and counterweights (m) and dimensions (L) are represented in the diagram. I have excluded the mass of the stabilizer framework. During panning, the centrifugal forces of m1 and m2 will cause tilt in a direction contrary to that of m3. For dynamic balance, we want (m1 L1)+(L2 m2)=m3 L3. If these forces do not balance, the stabilizer will tend to tilt during panning.

The above is a highly simplified representation of the dynamics.

Interesting Tiffen Steadicam analysis of balance dynamics here

A number of holes in the top plate accept the standard 1/4" camera mounting screw.

The gimbal housing can be slid along a channel, to set front to back balance.

Washers used as weights at the front of the tube.These,and the weights at the end of the tube, can be slid one side to the other to adjust balance. This is perhaps not an ideal system - making the structure of the stabilizer asymmetric could upset the dynamic balance.

Tidied up design for the front counterbalance weights, allowing for balance adjustment. The eccentrcally mounted weights can be rotated, moving the weight from one side to the other. The disc at the left is a UK 2 penny coin, with the plating on the face rubbed down.

Plastic bottle caps provide a softer finish for the weights on the tube. The weights are centralised.

Washers on the underside of the camera platform are used to set the balance.

A small lead weight can be slid forward or back along a plastic channel, to fine trim the front to rear balance.

July 2009

I have removed an earlier sliding balance weight in the plastic channel, and replaced it with a threaded wheel on a 4mm threaded length. The wheel has the outer ring of a ball bearing sandwiched between two UK pennies which have had the plating rubbed down. Inside the bearing ring, I have lead, as it is a heavy material.. I cut the supports from a transistor heatsink, and tapped a thread through the disc. This necessitated the repositioning of the rear spirit level.

Gimbal modification. April 2009.
Friction coupled slip ring for panning

This coupling allows the panning ring to 'slip', allowing smoother pans. The vertical shaft of the gimbal is fixed to the centre ring of a ball bearing, and the outer ring is actuated by hand. Three short sections of soft plastic sit between tthe inner and the outer rings, and provide the necessary friction. The plastic grips the outer ring, and there is movement between the plastic and the inner ring. The ball cage has been removed. There is no lubricant in this design, other than a trace film of oil. Too much oil or grease produces inconsistent friction.

I have designed and constructed my own gimbal system. I experimented with ball joints, and initially used one which I made up myself. It was good - smooth and fairly low in friction, but I was never really satisfied with it. Eventually I had the idea of a small universal joint combined with a ball bearing set into the top of the aluminium torch (flashlight to our American friends) which forms the handle. The bearing is a standard skateboard type - available quite cheaply in packs of ten. Conveniently, the head of the torch dismantles, allowing the bearing to be fitted in a very satisfactory way. The ball bearing is held in place by a threaded ring. Above the bearing in one design, I have a small wheel which will pan the camera with minimal effect on the camera's tilt. Using a finger on this wheel, I can also effectively lock rotation on the vertical axis to the handle, and contol pans by turing the handle. If the vertical shaft is off-centre in any way, the camera may display a tendency to turn when the handle is tilted, so some accuracy in construction is required. This is less of a problem with the ball bearing located above the universal joint Later designs use two bearings - one above, and one below the universal joint.

Gimbal Design #2 March 2009

This design employs a Traxxas 1951 universal joint, or 'half shaft'. These are used in radio control model cars. This represents an improvement over the first joint I used in August 2008.

The TRAXXAS 1951 universal joint, or half-shaft, and skateboard ball bearings. Two pairs of internally and externally splined shafts in a pack. 4mm and 8mm screws will cut a thread into these shafts.

I have tried replacing the original grease in the bearing with light 3-IN-ONE oill. This reduces friction in the bearing, but I'm not sure that it is appropriate for this application. It seems to produce uneven results.

Gimbal Design #4 July 2009

The Traxxas 5151 universal joint. This is a more substantial joint than the smaller 1951.

Basic assembly using two ball bearings and a Traxxas 5151 joint between them.

This is essentially a re-make of design #3, but using a more substantial joint - the Traxxas TRX-5151. In addition, I have taken measures to ensure a more accurate and adjustable alignment of the parts, and have allowed for easier disassembly. An aluminium ring around the top bearing (shown on the left) aligns it with the interior of the gimbal housing. 4mm machine screws connect the ball bearings with the universal joint.

The screw from the u-joint passes through the centre of the bearing at the top of the handle. View from below.

Underside of the gimbal housing. The upper ball bearing fits into the ring set into the gimbal housing.

Markings assist in adjustment of the gimbal housing.