@grahamguy A cheap solar-light style PV panel would probably be enough to keep a BT radio running for a long time. Garden light chassis.
@grahamguy That’d be the sort of thing I had in mi…
@grahamguy That’d be the sort of thing I had in mind. Something that could be dropped like lawn-darts from a distance. Cheap & hands-off.
They also require line of sight from a single cent…
They also require line of sight from a single centre point.
A theodolite & reflectors is how subsidence is…
A theodolite & reflectors is how subsidence is monitored currently. Theodolites are really expensive & delicate though.
The viral footage of landslides makes me wonder if…
The viral footage of landslides makes me wonder if there’s a low-power way of accurately monitoring the relative location of many sensors.