Ramon,
The external trigger URL should receive and interprete the JSON data that Meridian sends to it. So you need some dedicated PHP script or web application there, instead of pointing it to an arbitrary web site.
I created a short video around this question that shows the data coming in from the Meridian cloud and a web-app responding to that. This video is here: https://www.youtube.com/watch?v=DIF4SqyQkdI
Hope that video answers your question.
Example data coming in from Meridian (note it comes in in json format, not the format below):
(
[is_enter] => true
[campaign_id] => 5647648723828736
[broadcaster_id] => 85BAEDEA-1ACE-404B-874D-29AC21C18D58:16005:17491
[device_id] => 318e22ed-7450-39a6-bbad-c6eb19d3b79b:com.arubanetworks.campus
)
And if I have an (OAUTH) authenticated request, it has an additional authentication_token:
(
[is_enter] => true
[access_token] => bf5268e4a9baa3835c5be135e4715073f93a559e
[campaign_id] => 5647648723828736
[broadcaster_id] => 85BAEDEA-1ACE-404B-874D-29AC21C18D58:16005:17491
[device_id] => 3da7cf8c-7cae-3b71-8a73-d2a078c67744:com.arubanetworks.campus
)
The access_token can be used to lookup the user information (in my case my Name and e-mail) and use it on your server.
Herman