Servo Printer Head

eibbor

Hi,
· I've been looking at some parts, and I'm not sure what will accomplish what I need.· I'm looking at making a·kind of printer head·device.· Should I use a continous servo or a standard one?· I want to be able to keep track of position (like the head of a printer) so I thought standard, but then I want to run it over some distance (a foot or so like a flat bed scanner track), so I thought continous.

I looked at BS1USB and was going to use it to control the servos.· I'm basically writting a Visual Basic app that will send information to the servo to control it.· Am I way off on this part?· Should I really be looking at some other piece means to move and track the head?· Thanks in advance.

Mike Green

You probably don't really want either kind of servo. These are both R/C hobby servo motors and are not made for the kind of accuracy you probably want. You want either to use a stepper motor or make your own servo mechanism with a DC motor and some kind of position encoder. Take a look at the stepper motor controllers that Parallax sells (like the Little Step-U Motor Controller). They're pretty typical of what you might want. Pololu sells a motor controller with provisions for position feedback (www.pololu.com/catalog/product/392). You'd need a position encoder for it and I don't have any recommendations for that.

SRLM

You might try hacking an old scanner bed. These are set up with stepper motors already mounted in place, with pinpoint accuracy. If you get two, you can have a two dimensional printing surface. Since scanners typically can scan a 14" document, this is more than enough room for what you want. Plus, you might be able to get the old scanners for free!