Hi again guys, I have another question, this time regarding the start/home/neutral position of a sequence. To explain my problem I am building what is basically a hanging hexapod acting sort of as a flower. I’d like the first twitch to be in “bud” position, which means I’d like the middle servo on each leg to start at one extreme. If, in the sequencer, I set “neutral” to an extreme does it subsequently just describe the resulting angles in terms of 0-180 (or -0 to -180), or is that where a 1500 ms (compensated) pulse is considered to be? I hope that makes sense, it took me a while to figure out how to ask even!
I’m not sure if you are using the correct terminology.
Servos generally respond to pulse lengths of 1000uS to 2000uS with 1500uS being centered. With Hitec servos this roughly equates to 1000uS = -45°, 1500uS = centered, 2000uS = +45°. The Sequencer program allows you to calibrate the servos positioning as it relates to angles. It also expands the range from 90° (1000 to 2000uS) to 180° (500 to 2500uS) So you will set a servos min and max positions, the minimum and maximum positioning it can physically obtain, and tell it what angles these limits equate to. For example if the mechanical assembly servo is limited to -45° move it to that position, and set it as the limit. The pulse range will be around 1000uS. It might be 980uS or 1123uS, we don’t know till it’s tested. So after calibration you don’t worry about pulses which are arbitrary, only angles, which are easier to understand and work with.
After the calibration you can set any position, or set of positions, as “home” “neutral” or whatever you want to call them. But no real definition for these terms exist till you make the association. I.e. label a step.
I also hope this makes sense because my head exploded and I have to clean this up. lol
Servos are designed for pulse widths that vary from 1.0mS to 2.0mS, where 1.5mS is centered. In the normal range the servo will move +/- 45 degrees from the centered (neutral) position.
Most servos can be positioned to around +/- 90 degrees from neutral by expanding the range to 0.75mS to 2.25mS.
i would start at 1500 centered (neutral) position
hope this helps.
Dam beat me to it jim. 
Sorry for the clumsiness of my question. I think I was understanding the servo basics. What I was trying to address was the first twitch of the robot at the beginning of the " choreography" or maybe I could have said “step zero” in the sequencer. Like when I would turn my hexapod on (before I gutted it for this project) the first thing it would do is stand w/ it’s legs straight out and straight down, what if I wanted it to start with it’s belly on the ground like it was dead?
I think this answered my question;
"After the calibration you can set any position, or set of positions, as “home” “neutral” or whatever you want to call them. But no real definition for these terms exist till you make the association. I.e. label a step. "
Anyways I got it working, I was just afraid of wrecking my servos through my ignorance (which I’m about to display again in the electronics section!)
Just a short comment on “wrecking” your servos. If you run the servos off of an adjustable bench power supply (I’ve got a Protek 3003), you can set the voltage low, even less then 5v, and the servos will react slower and have less torque, and less opportunity to damage themselves.
Alan KM6VV
One can use rectifier diodes to drop the servo supply voltage by .7v per diode if needed when testing.