Knowledge Base

Problem

Users want to continuously stream live X,Y tracking coordinates from EthoVision XT to an external device (e.g., a Raspberry Pi or custom hardware) for real-time use, such as controlling a commutator or triggering external equipment based on exact position.

Details

This is commonly requested for EthoVision XT 17 and later versions in contexts such as automated commutator control or closed-loop behavioral hardware. EthoVision's Trial & Hardware Control module can trigger hardware events based on zone entries or other tracking conditions in real time, but it does not offer a standard built-in method for continuously streaming raw X,Y coordinate data to an external device over a serial, network, or GPIO interface.

Solution

1. **EthoVision XT does support real-time zone-based hardware triggers**: Using the **Trial & Hardware Control** module, you can configure rules that fire TTL signals or other hardware events when the animal enters a defined zone, crosses a threshold speed, etc. This is reliable for event-based external hardware control.
2. **Continuous X,Y coordinate streaming is not natively supported**: EthoVision XT does not provide a built-in option to continuously broadcast live X,Y position data to an external device (e.g., Raspberry Pi via serial or network socket).
3. **Workaround options to evaluate**:
- Use the **Hardware Control output** triggered by multiple small zones tiling the arena to approximate position-based outputs — though this is coarse and complex to implement.
- Investigate whether your EthoVision version supports any third-party API or data streaming add-on. Contact Noldus support to ask about current integration options for your specific use case.
- Consider alternative approaches where the external device (e.g., commutator controller) uses its own position sensing rather than relying on EthoVision coordinate output.
4. **Do not design critical external hardware** (e.g., a commutator) around continuous coordinate streaming from EthoVision XT unless Noldus confirms a supported integration pathway for your version — the latency and lack of a native streaming interface make this unreliable for real-time hardware control.
5. Contact Noldus technical support with your specific use case to get guidance on the best supported integration approach for your EthoVision version.