I’m posting this in case anyone else runs into a similar problem getting the Brain Gauge software set up.
I installed the Brain Gauge software on an old MacBook running MacOS 10.10 (my alternatives were Windows running inside VirtualBox on a Linux host or running under Wine; they had either the same issue or would not recognize the USB Brain Gauge at all). When I started the software, it would show me an error screen:
Your clock is ahead
A private connection to app.corticalmetrics.com can't be established
because your computer's date and time (Friday, January 14, 2022 at 3:19:15 PM)
are incorrect.
NET:ERR_CERT_DATE_INVALID
I run NTP on the MacBook and various other Linux computers in my house, so I was sure the Mac’s time was right. I even confirmed it with one of those “atomic” clocks that listens to WWV. On one of my Linux computers I ran:
curl --verbose https://app.corticalmetrics.com
to determine that both the app.corticalmetrics.com server and my Mac both had the correct time. So chalk up the Brain Gauge error message as being misleading.
I used the Mac’s Safari browser to visit https://app.corticalmetrics.com and it told me there was a problem verifying the SSL certificate. (Firefox worked fine - it must have its own list of root SSL certificates.) The problem was that MacOS 10.10’s root SSL certificate for ISRG Root X1 was old and expired in September 2021. This is the certificate authority for letsencrypt.org which is the authority for app.corticalmetrics.com. I found online instructions for downloading a new certificate and loading it into the Mac’s Keychain Access app in the System keychain.
After that, Safari was happy visiting https://app.corticalmetrics.com and so was the Brain Gauge software and I could finally set up my account.