Hi @marieke, thanks for the extra information on your project intentions. I am afraid that this is rather outside the scope and purpose of the Tobii 4C which is exclusively targeted toward regular interaction with a computer monitor.
If you have already purchased the 4C, then my suggestion would be to consider mounting a small monitor on the wheelchair and develop an application that has ‘zones’ on the monitor that can correspond to movement commands. You would need to include both the Tobii SDK and another SDK that somehow interacts with the chairs electronics, but perhaps that is not so difficult?
Indeed, with this route, as the application itself is purely for interaction purposes, you would not need to purchase the analytical use licence in this case.
I would mention that if you unplug the monitor, then the eye tracker would cease to work also.
Hopefully this workaround might suit your needs?