PiCar-X Calibrations

[Anthony Malary]

How's it going y'all I have been working on my robot, and I was able to get past basic set up and loading the software on to the pi correctly only trouble I'm having now is calibrations. Do any of you have any tips in that area? I'm able to get my steering calibration to work finally but the panning and tilt for some reason are not working correctly.  

[Bob Huss]

Hi Anthony,

There are 2 ways that I found to work for calibration of motor position.

If the robot has hard stops, then of course you can count digital pulses with a shaft encoder on the motor.

Or another way is to use an inclinometer chip mounted on the moving surface and that surface can be calibrated with a constant value that you determine. Some of these IC's output analog or I2C Digital signals, and can meaure 2 axis positions.

Hope this helps.

Bob Huss

On Fri, Jun 12, 2026, 9:43 PM 'Anthony Malary' via RSSC-List <rssc...@googlegroups.com> wrote:

How's it going y'all I have been working on my robot, and I was able to get past basic set up and loading the software on to the pi correctly only trouble I'm having now is calibrations. Do any of you have any tips in that area? I'm able to get my steering calibration to work finally but the panning and tilt for some reason are not working correctly.  

--
You received this message because you are subscribed to the Google Groups "RSSC-List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rssc-list+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rssc-list/b8545f8f-481b-4d68-bf08-9bbefbe6d748n%40googlegroups.com.

[Alan Timm]

So the trick is understanding that standard servos were never meant to be precision devices, and how to work with how each one is set up.

These almost always use a standard potentiometer internally, and the good news is that they're response by position is pretty linear.

So lets say you have a 180 degree servo, meaning it can turn 180 degrees end to end.

the trick is to discover what the minimum pulse value is for your 0 degree position, and the maximum pulse value for your 180 degree position.

Then you're going to map() your 0,180 range to whatever that pulse range is.  

Depending on what you're coding on the specifics look a little different, but that's more or less what you're going to do.

Unless you're talking about the raspberry pi pico, pi's don't do a great job of driving servos.  are you using a servo driver board?  What's your setup look like?

Alan