Radio Telescope

[Yander]

A group of students at my High School are building a Radio Telescope, I am doing a lot of the wiring and computer work. I was wondering if they new of a device for the computer that allowed the computer to control a switch. So basically instead of running the wires of a circuit to the terminals of a switch, they would run to the computer and could be controlled through software. I am also looking for a similar device for a potentiometer. The problem is we need to control these potentiometer from a room from 300 feet away but the electronic device the components are connected to are on the roof inside the telescope. If you know of any pieces of hardware
post suggestions.

[Ed_McCarron]

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2779

Serially controlled digital pot.  I've not used these personally, but they were mentioned in Nuts&Volts a while back.

[JCL]

There's about a million ways to get the job done, from simple to complex.

But I think a good way is to find someone locally who can help. I would suggest contacting your local university and talk to an Electrical Engineering professor. There are probably students who need a project to work on. Controlling a radio telescope might be a decent project for an undergraduate interested in Digital Design or something like that.

Ham radio hobbiests may also be interested in this project and be willing to lend a hand and some design skill.

Failing that, the simplest way to make something swtich on and off via PC would be a a few resistors, a transistor and a relay hooked to a PC parallel port.
Here's a page on this:
http://ourworld.compuserve.com/homepages/Bill_Bowden/page6.htm

The pot control is a little more complex, but there are still a few ways to do it. If you have to drive a real pot that already is in a system, you could use a stepper motor. For this application, single or half stepping is probably perfectly adequate. You can get simple chips that take 2 digital inputs, one for direction and one to tell the motor to step. The output will drive the wires of the stepper with the correct voltages.

[JCL]

I thought of another resource for skilled people.

Contact your local astronomy club. They probably have some people with electronics experience who would be interested in helping out with such a project. Again, google search is your friend. The Sky&Telescope website has a list with many clubs.

[Yander]

Most astronomy clubs are into optical astronomy, because you recieve more then a graph of radio energy when your done. We have help from a mechanical engineer but I think in the interest of time, we are going to wire it up to an actual control panel. We can always upgrade later. Thanks for the replies though.

[JCL]

Even though most amateur astronomers are into optical astronomy, many would jump to get involved with a radio telescope as well. I know I would, given the opportinity and some free time.

But good luck with whatever yu do. Sounds fun.

[ErikRuud]

You might also look into www.phidgetsusa.com or www.phidgets.com.

I imagine you could use one of their servo controllers to control a pot.

Or there is the mini-ssc at http://www.seetron.com/ssc.htm if you prefer using ther serial port.