Servo controller "two switches"

[Frazzle]

Hello, <p> I am trying to build a controller for a single servo. I don't know enough to design my own circuit but I am looking for a circuit that I could control a servo in this manor:<p> Two switches "if"
left switch ON = servo swings to full right
Right switch OFF
---------------- "if"
left switch OFF
Right switch ON = servo swings to full left
------------------"if"
Left switch ON
Right switch ON = Servo swings back and
fourth Left to right
continuous <p> If you need any more info or questions please ask me.

[rstofer]

There are hundreds, if not thousands, of ways to do this.<p>The average servo requires a pulse varying from about 1.0 mS to 2.0 mS repeating every 20 mS. 1.0 mS represents full motion in one direction, 2.0 mS represents full motion in the other direction and 1.5 mS represents a center position.<p>Now it gets down to how much effort do you want to put into the controller and how much do you want to learn on the way by. <p>Certainly the Basic Stamp can do the job but it's a little pricey. The good news is there is a TON of support around. Try www.parallax.com<p>The absolute easiest way to do it is with an OOPic R series board such as http://www.acroname.com/robotics/parts/ ... R-PKG.html My personal choice would be the OOPic S series board http://www.acroname.com/robotics/parts/ ... I-PKG.html and an RS232 dongle for programming such as http://www.awce.com/rs1.htm although the parallel cable supplied will work well if your computer has a parallel port. But, if this was going to be part of a larger project, I might go with http://www.acroname.com/robotics/parts/ ... C-PKG.html and just use the module in the project.<p>It can be done with any $2 PIC but the programming will be much more difficult. If I was going that route and didn't know a great deal about programming, I might look at Pic Basic (Pro, optionally) at www.melabs.com. They also have prototype boards for building up the circuit. The problem with this approach is the added cost of a chip programmer.<p>If you don't mind soldering, you might consider either the PIC (http://www.junun.org/MarkIII/Info.jsp?item=3) or OOPic (http://www.junun.org/MarkIII/Info.jsp?item=28) versions of the MiniSumo Mark III robot controller board. These are already set up to drive servos and if you use the OOPic version all you need is a serial cable. For the PIC version you will have to write a lot more code but the chip has a boot loader so you don't need a chip programmer. Plenty of sample code in the MiniSumo Mark III forum on Yahoo.<p>Too many choices! I would get the Mark III controller in an OOPic configuration, spend 3 or 4 hours soldering it together and, with a few hours experimenting, have it running. $49 seems fair considering everything is included!

[Gorgon]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Frazzle:
Hello, <p> I am trying to build a controller for a single servo. I don't know enough to design my own circuit but I am looking for a circuit that I could control a servo in this manor:<p> Two switches "if"
left switch ON = servo swings to full right
Right switch OFF
---------------- "if"
left switch OFF
Right switch ON = servo swings to full left
------------------"if"
Left switch ON
Right switch ON = Servo swings back and
fourth Left to right
continuous <p> If you need any more info or questions please ask me.<hr></blockquote><p>What do you want the servo to do when both switches are OFF?<p>What is the speed of the continous swing when both switches are ON?
Since there is no feedback from the servo on the position, you need to let the servo run all the way before you return.<p>Since you only need 2 inputs and 2 outputs to operate the servos, you could use the smallest PIC controllers: http://www.microchip.com/stellent/idcpl ... odeId=2060<p>TOK

[ProboticsAmerica]

Or you could go with a modification of one of the following - no programming at all in some cases, just use a 555 and a couple of transistors: <p>http://www.uoguelph.ca/~antoon/gadgets/servo2.htm<p>http://www.uoguelph.ca/~antoon/gadgets/servo3.htm<p>http://www.uoguelph.ca/~antoon/gadgets/servo4.htm<p>http://www.rc-cam.com/servotst.htm (uses a pic)