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.
nullwarp 3 days ago [-]
Hey this is really neat thanks for sharing definitely putting this on my list of things to put together.
Any chance the name has a connection to Twister?
utensil4778 5 days ago [-]
Very interesting. I wonder what effect this will have on microbial life in the soil?
These are shockingly bad. Please try to stay grounded and resist the temptation to generate any more.
hm-nah 5 days ago [-]
Wasn’t this part of Teslas work, to use ground as a conductor?
modeless 4 days ago [-]
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 4 days ago [-]
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?
mtreis86 4 days ago [-]
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
morio 4 days ago [-]
In the US, the neutral and ground are generally bonded in your breaker panel.
quickthrowman 3 days ago [-]
> 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.
Neutral and ground are bonded together in the service entrance. The neutral is a center tap off the utility transformer and the ground is usually a ground rod.
In older houses the service entrance is typically the main panelboard. In a house built after 2020, the service entrance will be a disconnect switch after the meter socket.
wongarsu 4 days ago [-]
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.
K0balt 4 days ago [-]
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 servíce entrance.
sidewndr46 3 days ago [-]
what you're describing would be an "IT system". Most of north america uses something like a "TN system"
The first transcontinental telegraph was a single wire that used the earth as a return conductor
2 days ago [-]
sidewndr46 3 days ago [-]
interesting that you mention this. I can't find any photographs of the line. Some depictions show two wires on poles. Others show what appear to depict a pole with a single conductor wire at the top.
utensil4778 2 days ago [-]
Yup. Short range runs could be two wires, it was more cost effective given the poor performance of the earth return system. Much longer runs were a single conductor on the pole. At either end you'd have a gigantic metal plate sunk deep into the ground to act as your return path. It had to be deep enough to stay wet, or the operator would have to dump water (or other fluid) on it.
There were also repeaters in the transcontinental run, the signal was just way too weak. These were initially electromechanical devices that dip a needle into a pool of mercury.
Things were wild before we really invented electronics.
Faaak 3 days ago [-]
How is drilling 90m cheaper than replacing a battery every year or so?
throwway120385 3 days ago [-]
Replacing a battery is an operating expenditure that you'd have to bear even in years where the weather is crap and your chemical inputs and fuel costs go through the roof. So you're paying someone relatively tech savvy to drive around to all of your fields replacing hundreds of batteries which could cost you a few thousand all in.
The cost of a well drilling rig and the time in nice arable soil is going to be a few thousand dollars. So you're comparing thousands of dollars a year to thousands of dollars once.
Rendered at 09:27:01 GMT+0000 (Coordinated Universal Time) with Vercel.
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.
Any chance the name has a connection to Twister?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6866705/
https://www.nature.com/articles/s43016-021-00449-9
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
Am I wrong?
Neutral and ground are bonded together in the service entrance. The neutral is a center tap off the utility transformer and the ground is usually a ground rod.
In older houses the service entrance is typically the main panelboard. In a house built after 2020, the service entrance will be a disconnect switch after the meter socket.
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.
https://en.wikipedia.org/wiki/Earthing_system#IT_network
There were also repeaters in the transcontinental run, the signal was just way too weak. These were initially electromechanical devices that dip a needle into a pool of mercury.
Things were wild before we really invented electronics.
The cost of a well drilling rig and the time in nice arable soil is going to be a few thousand dollars. So you're comparing thousands of dollars a year to thousands of dollars once.