To keep things nice and easy, I used the Adafruit 12 bit pwm servo hat: https://learn.adafruit.com/adafruit-16-channel-pwm-servo-hat-for-raspberry-pi?view=all and a standard library written in C++ for coding. There are python libraries, but I'm going to need to combine the Gimbal code with another C++ program,  object_detection_demo_ssd_async/main.cpp, which is used for the inference procedure.

Getting the gimbal moving at alarmingly crazy and jerky speeds was fairly easy, but to get it running nice and slow and smooth took a little bit more head scratching. I changed the lib-pca9685 https://github.com/paddygoat/rpidmx512/tree/master/lib-pca9685 simple.cpp file to get much better resolution than with the 'proper' servo.cpp one.

First of all, install the dependencies and libraries:

wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.58.tar.gz
tar zxvf bcm2835-1.58.tar.gz
cd bcm2835-1.58
./configure
make
sudo make check
sudo make install

cd /home/pi/rpidmx512-master/lib-pca9685
make -f Makefile.Linux "DEF=-DRASPPI"

Compile and build the examples on Linux Raspbian:

cd /home/pi/rpidmx512-master/lib-pca9685/examples
make

 Next, run the 'servo.cpp' or 'simple.cpp' file:

cd /home/pi/rpidmx512-master/lib-pca9685/examples && make && sudo ./servo
cd /home/pi/rpidmx512-master/lib-pca9685/examples && make && sudo ./simple

/**
 * @file simple.cpp
 *
 */
/* Copyright (C) 2017-2018 by Arjan van Vught mailto:info@raspberrypi-dmx.nl
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <iostream> 

#include "pca9685.h"
using namespace std; 
int msleep(unsigned long milisec)   
{   
    struct timespec req={0};   
    time_t sec=(int)(milisec/1000);   
    milisec=milisec-(sec*1000);   
    req.tv_sec=sec;   
    req.tv_nsec=milisec*1000000L;   
    while(nanosleep(&req,&req)==-1)   
        continue;   
    return 1;   
}   

int main(int argc, char **argv) {
    if (getuid() != 0) 
    {
        fprintf(stderr, "Program is not started as \'root\' (sudo)\n");
        return -1;
    }

    uint16_t OnValue, OffValue;
    PCA9685 pca9685;

    pca9685.Dump();
    pca9685.SetFrequency(100);

    //pca9685.SetFullOn(CHANNEL(0), true);                     // Channel 0 Full On
    //pca9685.Write(CHANNEL(1), VALUE(PCA9685_VALUE_MAX/2));    // Channel 1, Duty Cycle = 50 %
    
    int a = 450;                                            // Laser points upwards.
    int b = 900;   // b must be greater than a.
    int c = 5;
    int x = 500;
    
    pca9685.Write(CHANNEL(0), VALUE(a));                     // Channel 2, Duty Cycle = 20 %
                                                            // Max value = 4096. 20 % = 819.2 ~ 819 counts
    //pca9685.SetFullOff(CHANNEL(3), true);                     // Channel 0 Full Off
    
for(int d=c; d>0; d--)
  {
    for(x =b; x>a; x--)
    {
      pca9685.Write(CHANNEL(0), VALUE(x));                  // Up and down
      pca9685.Write(CHANNEL(1), VALUE(x));
      printf("Value d: %i", d);
          printf(" Value x: %i", x);
          printf("\n");
      msleep(50);
    }    
    for(x =a; x<b; x++)
    {
      pca9685.Write(CHANNEL(0), VALUE(x));
      pca9685.Write(CHANNEL(1), VALUE(x));
      printf("Value d: %i", d);
          printf(" Value x: %i", x);
          printf("\n");
      msleep(50);
    }
  }    

    pca9685.Dump();

    printf("\nOutput (%dHz):\n", (int) pca9685.GetFrequency());

    pca9685.Read(CHANNEL(0), &OnValue, &OffValue);
    printf("\tChannel 0: %04xh-%04xh, Full On\n", OnValue, OffValue);

    pca9685.Read(CHANNEL(1), &OnValue, &OffValue);
    printf("\tChannel 1: %04xh-%04xh, Duty Cycle = 50%%\n", OnValue, OffValue);

    pca9685.Read(CHANNEL(2), &OnValue, &OffValue);
    printf("\tChannel 2: %04xh-%04xh, Duty Cycle = 20%%\n", OnValue, OffValue);

    pca9685.Read(CHANNEL(3), &OnValue, &OffValue);
    printf("\tChannel 3: %04xh-%04xh, Full Off\n", OnValue, OffValue);

    return 0;
}

 It's all working nicely. Video to follow soon!