[contingencies]

Taking a computer out of the loop is the best way to guarantee speed and reliability.

Any safety response is going to rely on speed of detection and speed of response. Almost no sensor system will be faster than laser TOF and IMS. They are both very fast and very low power, you can afford to sense at high frequencies and this costs almost no power. Some models may include programmable interrupt lines to further reduce aggregate power utilization by avoiding the need for polling.

In terms of speed of response, anything within 1-2 seconds should be safe. Perhaps having an emergency actuation function in which the array is inverted to prevent convergence (and attract attention as a side effect!) may be safest. You could also cheaply and easily add a siren or audio announcement.

Bon travail et bonne chance!

[remipch]

> Taking a computer out of the loop is the best way to guarantee speed and reliability.

As suggested by pjc50 in another comment [0], a passive safety would be good for this application.

The main drawback being the space required to protect the entire danger zone.

> Bon travail et bonne chance!

Merci beaucoup

[0] https://news.ycombinator.com/item?id=41390704

[contingencies]

Well short of an enclosure, the standard for power tools is to project some form of laser mark. Only when the operator verifies the mark is in the correct position should they activate the system. This would be a viable approach for a CNC-shaped array of curves and would not require a complete enclosure, which has various downsides (windage, size, weight, potential for damage, suitability for rough terrain, etc.)