>> Can I feed the servo my >> over- and under-sized pulses, or do I have to add some gearing to avoid >> harming the servo? >> >I would also like to know the answer to this question. I have >always been told that most servos have 90 degrees of rotation >(except for the ones mentioned below), and that I should stay >within the 1-2ms spec. I assumed that giving them out of spec >signals was not a good idea. While it works, it is not recommended. Operation out of spec may give different results from different brands, different models, and even different units of the same model. That's why we have specs Most of the model airplane type servos will accept pulse from down around 100uS to well over 3000uS without going beserk. They can also be refreshed far faster than the 20mS spec. Here's a free one for you - if you refresh them faster, the servo has more apparent "torque" than one refreshed at 20mS. This is because the motor drive circuitry is active more, and the output cannot be changed as far before a correcting signal restores it. Again, this is out of spec! >I do robotics research and I need greater than 90 degrees of >rotation on my servos. I found one commercial servo that has >170 degrees of rotation: the Airtronics 94739 proportional >retract servo. There are also sail winch servos that have >rotations of multiple revolutions, but their positional >accuracy is poor (they add internal gearing to get more rotation). >I have been told that many connercial servos can be modified >to achieve a greater than 90 degree rotation. The people at >FMA Direct will modify their servos to do 160 or 180 degrees >(depends on the servo) for an extra $10--a great deal since >their servos are less expensive than most anyway (the nature >of the modification is "a change to the amp"). I haven't >purchased any yet, but I probably will in the near future. >You can contact FMA Direct at: > >FMA Direct >9607 Dr Perry Rd - Unit 109 >Ijamsville, MD 21754 >Email fmadir@fmadirect.com >Sales (800) 343-2934 >Technical service (301) 831-8980 >Fax (301) 831-8987 >http://www.fmadirect.com/ Have you tried any of their other products yet? What do you think? Andy ================================================================== Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 Hardware & Software for Industry & R/C Hobbies "Go fast, turn right, and keep the wet side down!" ==================================================================