Basic steps. Identify your wifi device (in my case wlp3s0), the enter monitor mode, use tcpdump to capture mac addresses and a short php script to switch between available channels:

sudo ip link set wlp3s0 down
sudo iw wlp3s0 set monitor control
sudo ip link set wlp3s0 up
sudo tcpdump -i wlp3s0 -e -ttttnn > tcpdump.log
sudo ./channel_changer.php

You can find out which $channels your device supports using iw list (it's the numbers in the 'Frequencies' section). There are about 14 on older g/n devices and more on the 5G access points. I switch channel every 0.2 seconds (same as Kismet's default channel hop time) which seems to work fine.

#!/usr/bin/php
<?php
$channels = array(
  1,2,3,4,5,6,7,8,9,10,11, 12,13,36,40,44,48,52,56,60,64,100,104,
  108,112,116,120,124,128,132,136,140,149,153,157,161,165);
 
while(true) {
        foreach($channels as $channel) {
        echo "Setting channel: #$channel\n";
        exec("iw dev wlp3s0 set channel $channel");
        usleep(200000);
        }
}
 
?>

I've made some graphs:

• General scan #2 - Sat July 6th 2019 8am-11:30am - All data grouped in unique MACs per 1 minute period
• General scan #3 - Sat July 6th 2019 8am-11:30am - As above, known (previously seen the hours/days before) devices/equipment filtered - an example of identifying a group of passerbys (Orange walk outside my window at 10:40am)
• General scan #4 - Multiple days showing the weekend and spikes, at 8am and 5pm, of people passing by to and from work.

I'm still working on analysing an entire uninterrupted month to get some general statistics on wifi use around my area. Updates and code to follow.