I have a vague memory of somebody using recordings of angry bees to scare away elephants with some kind of tripwire or infrared trigger to start playback. My memory is that it worked well for a while but the elephants eventually worked out that they weren't real bees so the raids re-started. Hopefully this version in Chantaburi has a better longterm future.
It certainly is a nice solution. I do not want to be pessimistic, though I do have my doubts how to implement this for the large border areas with farms around Kui Buri or Pala-U area. It remains a very difficult problem to solve especially with an ever growing population of humans (and perhaps in some of these areas also growing population of elephants.)
All the protected areas are mostly mountainous, and all flat lowland is taken by humans.