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[woodced]

Hi, I'm looking into doing a bit of a Netduino project for the first time and I want some product recommendations and general guidance. I'll point out at the outset that my electronics knowledge is limited, though not completely non-existent. I'm looking at Netduino because my C# is good and I did a little .net MF coding a few years back. I'm investigating the feasibility of creating a camera jig with a Pan/Tilt head that can be computer controlled. I cannot justify or understand the cost of the commercial products (the VZMC50 from http://www.varizoom.com/ is $2400 and that's just a couple of pots connected to some steppers) and so want to roll one out myself. I want my pan/tilt head to be Netduino controlled and to have silent, fluid motion in both the pan and tilt directions. The rotational angle in each dimension needs to be no more than 180 degrees, possibly less. I'm more interested in fluidity of motion than in precise and repeatable positioning of the head. However, position should be tracked to within 0.1 degree and should be fed to a listening computer which provides input (hence the micro-controller). The head will carry a weight of no more than 1.5 kg. I was initially going to use the Netduino to drive a pair of servos and to find some gears that would be suitable for the project. I've come to the conclusion (possibly ill-founded) that with the products I've found (e.g. Hitec RC-model sail winch servos) this would be noisy and would result in unacceptably jagged motion. The alternative seems to be to use a pair of DC motors that are appropriately geared and have optical encoders. The aim would be to use a motor controller to control the motors. The motor controller would interface with a Netduino which would track the position of each of the motors relative to some arbitrary calibration point by interfacing with the encoders. The idea would be that the Netduino software could be written to adjust the input of the motor controller as movement begins and ends so that the controller gradually increases the motor current to provide gradual roll-on and roll-off in the camera's angular motion. Has anyone got any product recommendations for the motors, encoders and controllers for this project? Is there anything I'm missing, or is there any advice anyone can give? There are loads of DIY Pan/Tilt heads on the internet, but most seem not to be concerned with the fluid quality of the pan. I don't want to spend a huge amount of money on this, though I don't mind using some off-the-shelf components in order to make the whole system easier to roll-out or packet. Any advice/recommendations much appreciated.

[ItsDan]

Stepper motors I would think would be enough, they come in a variety of step increments, and some can half-step, doubling their resolution. Fluid/silent motion means you want good bearings for any moving parts, and you want to make sure you ramp up/down your movement, probably just in software. You may want to use a belt between the motor and motion assembly and not direct drive it to help smooth it out more.