[HN Gopher] Agricultural IoT system sends power through the soil
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Agricultural IoT system sends power through the soil
Author : rbanffy
Score : 43 points
Date : 2024-05-03 09:05 UTC (2 days ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| hm-nah wrote:
| Wasn't this part of Teslas work, to use ground as a conductor?
| utensil4778 wrote:
| The first transcontinental telegraph was a single wire that
| used the earth as a return conductor
| modeless wrote:
| The entire electrical grid relies on the ground as a conductor.
| If your electrical outlet has two wires, one of them is
| connected directly to the literal ground via a metal post
| buried outside your home. If it has three wires, usually two of
| them are connected directly to the ground.
|
| In most electrical systems one of those ground wires is also
| connected to a neutral wire that leads back to the generator.
| But there do exist "Single Wire Earth Return" systems where the
| neutral return wire is omitted and everything still works.
| https://en.m.wikipedia.org/wiki/Single-wire_earth_return
| polishdude20 wrote:
| Wait.. if you've got two conductors it's neutral and hot.
| Neutral, as far as I know isn't connected to a literal metal
| post in the ground. That would be the third wire which would
| be called ground and is connected to a metal post.
|
| Am I wrong?
| morio wrote:
| In the US, the neutral and ground are generally bonded in
| your breaker panel.
| K0balt wrote:
| Maybe depends on where you are? All the systems I have
| worked on in a few countries have the neutral connected to
| earth ground at the feed point for the building, at the
| service entrance.
| wongarsu wrote:
| The literal ground doesn't have the same potential
| everywhere. This is obvious in case of lightning strikes,
| but also happens in normal circumstances. You as a human
| standing on the ground are mostly at ground potential. If
| neutral was connected to ground at the nearest substation
| or the next power plant but not at your home you would get
| an electric shock whenever you touch a neutral wire because
| of the difference in ground potentials.
|
| Neutral can _also_ be connected to a neutral line on the
| grid. But you pretty much always want to connect it to the
| local ground through a literal metal post.
| mtreis86 wrote:
| In the US, usually neutral is connected to the center tap
| of the transformer on the street, literally hooked to the
| middle of the winding. It is brought to ground level by
| hooking it up to the ground at the house, but the
| signal/power goes back to the transformer because the
| resistance is far lower than going through ground. That's
| why you have two power rails in the breaker box, the two
| hot wires coming in are 220v apart, the neutral is in the
| middle making for a pair of 110v rails at 180degree phase
| angle apart. See https://en.wikipedia.org/wiki/Center_tap
| utensil4778 wrote:
| Very interesting. I wonder what effect this will have on
| microbial life in the soil?
| datameta wrote:
| Potentially positive.
|
| https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6866705/
|
| https://www.nature.com/articles/s43016-021-00449-9
| alexose wrote:
| This is a really cool idea for lots of reasons, but especially
| because you could leave sensors buried forever. This lends itself
| well to long term soil monitoring-- A somewhat unsolved problem
| especially in no-till environments.
|
| Agriculture is a harsh place for sensitive electronics. My
| approach has been to make them cheap enough to be nearly
| disposable (shameless plug, https://github.com/alexose/dorothy),
| but this still requires a lot of human intervention to keep
| everything chirping.
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(page generated 2024-05-05 23:01 UTC)