I am reading about the various so-called Grama and other Shabbat switches developed in Israel for use in hospitals and security situations.
It seems that there was one solution created by Rabbi Halperin of the Institute for Science and Halakha, and a separate mechanism made by Tzomet.
I get the impression that they differ as to their methods, but I didn't find a detailed explanation of the different mechanisms and what the underlying difference of opinion was between the two.
Can anyone recommend a good source material for this? (I can get to the Otzar Hahokhma if necessary.)