Basically, you pull this thing behind your car or truck, which is lighter than a real tractor and decently easy to transport.
The secret to this machine is that it follows your instructions over time, rather than being operated by you. In other words, you import a simple 3D schematic, and it digs all day until it is done.
I was thinking the first two arms could extend out, maybe if needed. The entire digging gear fits in the weighted box, which pulls behind a vehicle.
The actual shovel is tiny, but it is more careful about unexpected 'treasures' and works continuously and perhaps quietly until done. The possibility of it moving itself may require too much additional AI, but it could recognize where it is and dig from wherever the operator moves it to.
That way a nerdy person like me can dig a basement or whatever, without having to buy transport equipment or learning to drive a tractor. I was thinking of having replaceable sharpened blades/cutters on the shovel front for better efficiency. It could run on wall electricity or generator.
Ok enough for random ideas today.