Aerator robot using existing perimeter

[Vertigo]

Hi all,

Since I already have a commercial mower robot, Im considering building a core aerator robot based on ardumower. The idea is to have a robot drive around and randomly drill holes in the soil with a drill or small auger. Core aeration is one of the best things you can do for your lawn, but core aerators are big and very expensive machines. They are also hard to rent where I live, so much so that this summer during lockdown I couldnt get one, and used a rather extreme alternative; I drilled 1000+ quite large holes with a pressure washer. Im not sure I recommend doing it, but the effect was beyond my wildest expectations (

).

Thats clearly not a job I want to do every year, so why not have a robot drive around slowly and drill even just 10 or 100 (smaller) holes per night and constantly aerate your lawn? Im actually surprised no one seems to have done this yet, commercially or DIY. For mowing there are all kinds of solutions, for aeration, not so much (other than renting huge machines). People mount spiky wheels on their robots, but that doesnt achieve the same result, that doesnt go deep enough and ends up compacting the soil around it. You need to get soil up and put it on top.

Anyway, Im only in the brainstorming phase, and my first concern is the perimeter wiring. I know I could just add some relays to cut the signal from my ambrogio docking station and send my own signal on the same wire. But would it be possible to tune ardumower to the signal of my existing robot, so I can just use the existing perimeter wire and sender ? I havent yet read on on how autodocking works, so I have no idea if that could even work with a second dock on the same wire, but even if that cant work, I can live with that for now.

If anyone has ideas or suggestions or feedback on the idea of an aeration bot, Im all ears. Feel free to respond in German btw, I understand it well enough, I just cant write it

 

[bernard]

It's certainly a big work but no particular issue.

But would it be possible to tune ardumower to the signal of my existing robot,

Certainly not.

ust add some relays to cut the signal from my

It's the best solution and the relay can easily be managed by the ESP32 sender.


Replace DOOR Station Motor by the Relay coil and use one of the 2 Mic to be sure that the AMBROGLIO MOWER is into station before swap to new signal.
Adjust the code according.

second dock on the same wire

Using RFID tag it's easy to dock outside the wire (Max 1 or 2 Meters distance from wire). So the ambroglio can work without issue.

 

[Vertigo]

Certainly not.

Why not? Just curious. I assumed those commercial mowers use the exact same principle and comparable frequencies; wouldnt it "just" be a matter of logging the signal on the wire and then adjust the filter to match that signal as best as possible? Im also curious about this for another reason; I might want to create a second loop in my front yard without laying wires from back to front (and then just carrying my robot there), for that I would need a second signal generator that spoofs the original. Even if its not a perfect replication, it may be good enough?

use one of the 2 Mic to be sure that the AMBROGLIO MOWER is into station before swap to new signal.

Im not sure I follow that. Or does the ambrolgio not transmit a signal on the perimeter wire when the mower is charging?

Using RFID tag it's easy to dock outside the wire (Max 1 or 2 Meters distance from wire). So the ambroglio can work without issue.

Gotcha, Ill read up on that. Do these commercial robots also use RFID?

 

[roland]

How does the signal of the Ambrogio looks like? Inside the perimeter and outside of the perimeter?

 

[Vertigo]

How does the signal of the Ambrogio looks like?

I have absolutely no idea! Maybe Ill just construct a receiver as per ardumower instructions and see if I can detect something and log it. Or better yet, buy, borrow or steal a scope, though I wouldnt know how to use it...


Continuing my brainstorm; for the drill itself, I was looking for a motor, and to get a feel of what kind of speed, power and torque are required, I just tried with a long 12mm diameter stone drill in a cheap 12v cordless drill, and that works ok on my lawn (best at low speed setting, 300rpm). And actually gutting a cordless drill may be a reasonable starting point anyhow, why reinvent the wheel?

The amount of torque I feel is substantial, and some downward force is needed as the drill quickly fills with soil (its not an auger, the only ones Ive seen so far are too wide, and are going to require too much power). This is going to have to be a rather heavy robot. Maybe a 12V car battery wouldnt be the worst option to power it.

For the vertical movement, I looked at my 3d printer for inspiration. And then realized you can buy a complete 3d printer kit for ~100 euro. For a proof of concept, that would give me 5 stepper motors, a ramps controller board, a complete Z axis that should be powerful enough to carry the drill and push it in the soil, albeit slowly. And I might even be able to use timing belts and use the other stepper motors to actually drive the contraption (although again, really, really slowly no doubt).

 

[bernard]

Im not sure I follow that. Or does the ambrolgio not transmit a signal on the perimeter wire when the mower is charging?

All my suggestion are based on the fact that it's not possible to reuse the ambroglio signal.
So before start the drillMower and swap the wire to ardumower sender, you need to be sure the Ambroglio is not working.
For the signal maybe Roland can help but it's really very complex and it's why i tell you "certainly not"

 

[roland]

Steppermotors need a lot of energy because they have a constant current independent of the speed. Not really optimal for a Robot.

 

[Hartmut]

Die einfachste Art dein Orginalperimeter zu verstehen ist eine Reihe LED am Perimeter Stecker parallel zu schalten (mit Vorwiderstand).
Ich sah bei mir, das der Empfänger ein Dualparameter war, was High sendet wenn es auf die Schleife trieft. Man sieht genau wie der Rover beim Umfang mähen auf dem Draht navigiert.
Wenn die Signale und der Ablauf passen kannst du diese weiterhin verwenden. Der Perimeterempfänger hat mit der Hauptplatine nur die Spannungsversorgung gemeinsam. Empfänger bei mir 5V. Wenns nicht passt halt noch ein Gatter/Logikwandler dazwischen.

Ich würde versuchen den Orginalperimetersender als Ersatzteil zu bekommen und mit dem PCB 1.4 zu nutzen. Dann kann der Rest Ladestation, Draht, Perimetersender so bleiben.
L.G Hartmut

 

[Vertigo]

Steppermotors need a lot of energy because they have a constant current independent of the speed. Not really optimal for a Robot.

You can power them down, so they dont consume anything when not moving. I doubt the Z axis will drop when not powered (or more than a few mm which matters on 3d printers, but not here); on my prusa, I need to push really hard to move the Z axis without power. but even if I need to keep those powered, my robot will be spending a ton of energy drilling and not a whole lot driving or holding the drill up, so Im not very concerned. Especially since I need weight and so not only can afford a large battery, I may need an oversized battery just for the weight (and to power the drill).

Mind you, I agree stepper motors of a 100 euro 3d printer will be not be ideal to move this contraption, but for a proof of concept it may work well enough.

 

[roland]

@Vertigo, what kind of Ambrogio do you have? Can you tell me the diameter and the width of the front wheel? Thank you very much.

 

[Vertigo]

I have the baby model, the L15. Probably not want you wanted, but the front wheels are ~80x32mm