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???
04/29/09 05:08
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#164920 - Open-loop
Responding to: ???'s previous message
For high speed (but lower precision) you would normally use an open-loop solution, i.e. no feedback. You drive a voice coil by giving a voltage. The higher the voltage, the larger the deflection. Within a limited range, the voice coil is almost linear.

Besides HDD heads, you may also look at loudspeakers. They are built for higher frequencies than a normal HDD head, which allows you quicker movement of the laser beam. Using two voice coils can give you two-dimensional deflection of the beam.

List of 55 messages in thread
TopicAuthorDate
Circuit name for a "servo"            01/01/70 00:00      
   Something like that?            01/01/70 00:00      
   Specific vs General            01/01/70 00:00      
      Servo motor            01/01/70 00:00      
         Context            01/01/70 00:00      
            Equivalent is a strong word            01/01/70 00:00      
            yebbut            01/01/70 00:00      
            Yes, it's just another misnomer            01/01/70 00:00      
   To move data transfer between One proccessor to another one            01/01/70 00:00      
      I have never hear that            01/01/70 00:00      
         Typo ?            01/01/70 00:00      
   I misnamed what I want + info            01/01/70 00:00      
      Open-loop            01/01/70 00:00      
         I've got an old voice-coil FDD ...            01/01/70 00:00      
            Voice coils in HDD for quite some time            01/01/70 00:00      
      Look at commercial stuff for inspiration            01/01/70 00:00      
         Hinged mirror            01/01/70 00:00      
            What type of hinge            01/01/70 00:00      
               What Chico has is several angular options            01/01/70 00:00      
                  silicone            01/01/70 00:00      
                     That might work ...            01/01/70 00:00      
                        Precision relative to amount of modulation            01/01/70 00:00      
                           I don't quite see it            01/01/70 00:00      
                              At least two alternatives            01/01/70 00:00      
                                 There's another way ...            01/01/70 00:00      
                                    Rotating mirrors of limited use            01/01/70 00:00      
                                       Link about hazards            01/01/70 00:00      
                                          Safety First!            01/01/70 00:00      
                                             Today, rasters are hard for microcontrollers            01/01/70 00:00      
                                                Not necessarily! They don't have to be involved ... much.            01/01/70 00:00      
                                                   Easy first when all parts of the chain are easy            01/01/70 00:00      
                                                      It depends on how much you want to draw            01/01/70 00:00      
                                                         Still pushing rotating mirror, ignoring the problems            01/01/70 00:00      
                                                            Per, I think you've lost your way            01/01/70 00:00      
                                                               Stampede            01/01/70 00:00      
                                                                  One thing at a time            01/01/70 00:00      
                                                                     Finally noticing the lack of information from the OP?            01/01/70 00:00      
                                                                        GREAT links            01/01/70 00:00      
                                                                        It's about what people already are doing            01/01/70 00:00      
                                                                           Not DIY            01/01/70 00:00      
                                                                              Let's consider the commercial products.            01/01/70 00:00      
                                                                                 The man who rejected video uses video as his example...            01/01/70 00:00      
                                                                                    You mistake my viewpoint            01/01/70 00:00      
                                                                                       Chico might care            01/01/70 00:00      
                                                                                          The reason I don't care ...            01/01/70 00:00      
                                                                                             I wouldn't be surprised if Chico has a working projector            01/01/70 00:00      
                                                                                 Where ?            01/01/70 00:00      
                                                                                    8 angled mirrors...            01/01/70 00:00      
                                                                                       Ah.            01/01/70 00:00      
                                                plot rates            01/01/70 00:00      
                                                   Probably better than average, unless small angle            01/01/70 00:00      
                                                      In order to have high speed, you must have low mass            01/01/70 00:00      
         Homebuilt laser projector            01/01/70 00:00      
            EXCELLENT!            01/01/70 00:00      
               Yes, excellent            01/01/70 00:00      

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