A little help with our Senior Design Project

[shuluke]

Hello,

I am currently in a group that is building a polarization camera that will be used for future research and i am having a few problems looking for ideas on how to control the cameras. We have a basic camera already built, but we want to "Upgrade" it. The cameras are currently mounted in a box, and have to be manually configured for movement up/down/left/right/etc.. We want to make a controller for it, so that it can be controlled by a computer to move the way we want. The only problem is that we cant find the controllers to use. The camera "case" is less than a cubic foot but we would like to make it smaller if possible. Every camera mount controller i have found on the internet is bulky and would be hard to use. If anyone has any ideas.. any help would be greatly appreciated. I can give more information if needed..

Shuluke

 

[theinfamousbob]

Use the parallel port on an old computer, QBASIC, and some high-torque servos or steppers. good luck!

 

[pebe]

Hello,

I am currently in a group that is building a polarization camera that will be used for future research and i am having a few problems looking for ideas on how to control the cameras. We have a basic camera already built, but we want to "Upgrade" it. The cameras are currently mounted in a box, and have to be manually configured for movement up/down/left/right/etc.. We want to make a controller for it, so that it can be controlled by a computer to move the way we want. The only problem is that we cant find the controllers to use. The camera "case" is less than a cubic foot but we would like to make it smaller if possible. Every camera mount controller i have found on the internet is bulky and would be hard to use. If anyone has any ideas.. any help would be greatly appreciated. I can give more information if needed..

Shuluke

Interesting subject. I am thinking that you will only need pan and tilt. I have seen on TV, police monitoring crowd scenes. They seem to use a joystick and such a system should not be difficult. These are my thoughts:

A joystick connected to a games port can be read in QuickBasic. There is a problem. Games ports seam to be ‘old-hat’ as is DOS’s QuickBasic. My WinXP machine has no games port though it will run QB programs. Joysticks seam to be USB these days. But no doubt that could be got around. Anyway, by whatever means, the two axis of the stick could be read and a program could be written to translate them to give suitable outputs at the serial port.

At the camera, I think that instead of using servos with feedback, it would be easier to use ordinary motors – suitably geared – for motive power. The power source would be PWM.

The direction of the stick would give direction of travel, and the amount of deviation would equate to motor speed. The stick would be put hard over for fast pan, then bringing the stick back toward normal would slow the motor down as the camera got close to its intended position. A microcontroller would do the interfacing.

Control data from the serial port would be one byte each for pan and for tilt, repeated continuously. The first bit of each byte would identify which function it was – a ‘1’ for pan and a ‘0’ for tilt. The second bit would indicate direction of rotation. That would leave 6 bits to give a speed range.

The micro would read the data from the PC and give simultaneous outputs to the two motors. Each motor would be driven from an ‘H’ bridge. Pulses would be applied to drive the motor in either direction. Pulses would stop when the final position was reached.

I hope that may give you some food for thought.

 

[shuluke]

Thanks for the help. I will look into this and ask more questions this weekend once me and my group have talked about it. What is a "H"bridge?

Shuluke

 

[pebe]

Thanks for the help. I will look into this and ask more questions this weekend once me and my group have talked about it. What is a "H"bridge?

Shuluke

It's a method of connecting a motor so it can be run in forward or reverse. This link gives a good description

**broken link removed**