Need help setting servo center positions in 12 bit Maestro

Support Servo controllers and servos
1

I have mounted my servos but they aren’t perfectly centered with the control center status sliders at the 1500 position. Is the Channel Settings 8-bit neutral setting supposed to offset the servo positions for centering? If so, I can’t get the 8 bit neutral settings to alter the servo positions.

Thanks, Jim

2

Hello, Jim.

Individual servos will vary, so a target of 1500 will not always center a servo exactly. This is something you might have to correct for in the control center using trial and error. Also, the 8-bit neutral setting is documented in section 4.e of the Maestro user’s guide, and it does not alter servo positions in the way you described.

-Ken

3

Thanks Ken for your reply. Section 4.e probably states precisely what 8 bit neutral technically does, but it doesn’t express much to the casual user.

For a six-leg insect walker, using the trial and error method is tedious. My 9 year old can program it to walk but employing pencil and paper and a calculator to make it precise breaks the attention span. Perhaps it’s time for him to learn spreadsheets!

I will add adjustability to the next version made from laser cut acrylic, but I was hoping there was a variable per servo for offset or centering.

Thanks much, Jim

4

Hello, Jim.

Just in case you didn’t know, a useful feature of the Maestro Control Center is the ability to copy and paste data between a spreadsheet and the sequencing tab.

The 8-bit neutral setting can be used to calibrate the servo channel, but it only effects 8-bit commands. The SERVO_8BIT script command uses values 0-254 to set your servo’s position (127 is neutral). An 8-bit target of 127 corresponds to a pulse width of 1500 microseconds by default; however, if your servo centers at say 1580 microseconds, then setting the 8-bit neutral to 1580 will in a sense calibrate the servo position.

Have you tried removing the servo horn and adjusting it manually to be more centered when at the 1500 target? This might be an easier solution.

-Ken

5

Hi Ken,

We’re just learning and at the level of saving frames, saving and applying scripts, and just now looking at the scripts. The insect walks!

The the splines on the servo horns limit the accuracy of the centering mechanically, so I was hoping for an easy offset. We did make a spreadsheet to calculate the moves with the centering offsets included and saved frames with the moves and it works fine.

Thanks for your help,
Jim