Inspired by this blog post but found the scipt didn't work quite right because it used single quotes (') instead of double inside the JSON body. The tweaked scripts look like this:
#!/bin/sh
username=admin
password=changeme
baseurl=https://localhost:8443
site=default
cookie=/tmp/unifi_cookie
curl_cmd="curl --tlsv1 --silent --cookie ${cookie} --cookie-jar ${cookie} --insecure "
${curl_cmd} --data '{"username":"'"$username"'", "password":"'"$password"'"}' $baseurl/api/login
${curl_cmd} --data '{ "led_enabled": true}' $baseurl/api/s/$site/set/setting/mgmt#!/bin/sh
username=admin
password=changeme
baseurl=https://localhost:8443
site=default
cookie=/tmp/unifi_cookie
curl_cmd="curl --tlsv1 --silent --cookie ${cookie} --cookie-jar ${cookie} --insecure "
${curl_cmd} --data '{"username":"'"$username"'", "password":"'"$password"'"}' $baseurl/api/login
${curl_cmd} --data '{ "led_enabled": false}' $baseurl/api/s/$site/set/setting/mgmtThe rest of the post is still accurate and I encourage you to check it out for more details on exactly how to schedule using cron.