Binary Sensor controlled through the AOI

As a project in university, we are making a presence detection system based on thermal camera. This software will be running on a different computer than HA and I would like to connect it as a Binary Sensor.

I think the most straight forward way to connect it is to make HA API call every time the presence detector changes state. But I am not sure how to add a ‘dummy’ device, that I could then control through the API.

I know about the RESTFUL Binary sensor, but I think that works the other way around – HA makes request and sensor answers.

Am I going in the right direction? What is the best practice to add a dummy device? Thanks, Miki