pan and tilt remote head for a camera setup

[subby]

Hi there.

Hoping someone can point me in the direction of doing some research into finding out how to build a remote controlled pan and tilt head for a camera setup, I noticed the you get the kits with or without servos, I would need a servo that would be able to push around 150oz at least with 360 degrees of rotation, the speed would not need to be more than about 45 degrees a second (majority of times it would be ALOT slower), also am I able to set it up so it would rotate 10 degrees pause for a few seconds (takes photo) then moves another 10 degrees, repeat.... I also would like to be able to control it via a Mac computer.

Any help/direction would be greatly appreciated.

Regards

Subby

[Nick Reffold]

Hi Subby

Yes - I have been thinking about doing this for a while and have done some solid modelling (or doodling). I reckon that the camera cradle needs to be designed for the specific camera so as to get the gimbal axes right on the CG for that camera (and power pack). Maybe it could be done with some lightply sandwiched in glass cloth / epoxy. Sail winch servos could provide the motion from a separate RX / battery.

Does anybody out there have any ideas whether I could strip down and use an old Fuji digicam? My daughter's friend dropped it and broke the shutter BER butthe rest seems OK. I would love to get it into a live video downlink as well.

Lets see if we can do a 'community design job'. I have taught structural and mechanism design for a few years before recent early retirement. I am a complete dud with electronics, however.

Regards

Nick

[muc]

one of these and a modified servo could work?

http://www.servocity.com/html/robotzone_servos.html

[Nick Reffold]

hi muc

I can't really see that this gives any great advantage over a sail winch servo. I am wary of declarations of power increase without telling us what else goes in, i.e. more battery drain. What they call power has units of torque. Power is torque times rotation rate. This is a simple gear box which would necessarily have an efficiency of less than 100% - don't you just hate entropy?

[MatC]

The "###oz in of power" is marketting speak and can safely be ignored. Those mods both increase torque and decrease speed by a factor of five. Power output is the same (less gear friction, about 5 to 10%). Battery drain is the same (apart from friction). They are just a 5:1 gear ratio with the pot relocated from inside the servo to outside, on the reduced-speed gear. Nice idea, although the servo will settle five times slower than normal too (probably no bad thing for most of the applications it will have).

For electronics: you want a microcontroller... see about 300 other threads in this forum. There's a lot of stuff on generating the correct PPM signal for a servo. Pretty easy stuff, but you do need to handle the computer interfacing (use serial or something?) and micro controller programming.

[Nick Reffold]

I was thinking along the lines of one of these...

http://www.robotica.co.uk/robotica/ramc/products/servo_control/servo_control.htm

and a wireless modem.

Sail winch servos can handle more than 360 deg. rotation. I have some GWS SW servos that will give 1/2, 1 or 6 full 360 turns. They cost me about £15 - around $26.40. Suitable gearing could be made to produce desired turn requirement and / ort resolution. Rob an old / damaged servo for bearings / gears?

I am guessing that you would need around 180 deg elevation and about 1 1/2 turns in azimuth. You might go for a third axis so that you could compensate for aircraft attitude.