wirelessly controlling a pot

unlimited1320

Ok guys I am not very experienced with this so bare with me. I have a project I have been brainstorming about for a few days now. I have researched it and learned as much as I understand and now I am hoping to get some input form you guys. Here is the plan
I want to wirelessly control a pot from about 15 feet away and also a single contact used as well. The unit im working with gets controlled by a foot pedal.. Inside the foot pedal there is a 1k 1t 2 watt pot and a contact switch that turns the circuit on. I can relocate the pot and switch to a box mounted to the unit and I want to control it from 15 feet away. Now can I use a new pot mounted in the existing pedal and run it to a controller and send the signal to the box housing the original pot and control that with a 360 degree servo and a belt and pully? and also have it activate the switch in the box. How would I achieve this? What would I need to purchase and how hard would it be to program? Its for a friends school project so I dont want to spend a fortune doing it either. One more thing to add. There is another device which uses different frequencies close by. So interference may be a problem, Im not sure if it will so I will have to try it out and see . Any way to do it infrared? Would it have to be in a direct line of sight?
Thanks guys

Mike Green

The easiest thing to do is to use a servo motor as you propose to remotely turn the 1K 2W Pot and to use an appropriate relay to take the place of the switch. A Stamp can control the servo directly and, with a switching transistor, can activate the relay. Nuts and Volts Column #6 shows how to use a switching transistor with a Stamp and relay or small motor. For the wireless communications, I'd use a pair of xBees although you could use infrared. Direct line-of-sight would be the most reliable for IR use, but, in a room without a lot of windows and without direct sunlight, the IR could work without line-of-sight.

On the controlling end, you could use another Stamp to measure the pot resistance (using the RCTIME statement) and the state of the switch and transmit both to the remote unit.

xBees are addressable. Even though they use the same band as Bluetooth and WiFi, all 3 can coexist amicably.

ElectricAye

I see this is your first post. Welcome to the forum.

Mike's advice is, of course, totally golden.

You can find Xbees here:
http://www.parallax.com/tabid/768/txtSearch/xbee/List/0/SortField/4/Default.aspx

and you'll need two of them, so the Xbee method is going to add roughly $50 to the project.

The IR (infrared signal) method would be cheaper but, as Mike said, you must consider what might get in the way of the IR light. An IR method would work something like your IR TV remote control: if somebody or something stands in the way of the emitter or receiver, it won't work.

If you've never worked with microprocessors before, then you should allow yourself at least a few days of dedicated effort to learn how to program them and interface them with the Xbees, IR modules, etc.

hope that helps you scope things out,