inventor needed

[Tim Lamb]

you need a lot of them. 3 rows 15" apart on a 30x25m lawn. That is how I did the last spraying job.

[Tim Lamb]

In message , fred writes

I think lawn sized rotary spreaders are available. You need a linkage to shut off the spreader for the turn at the headland.

[Nightjar]

You wash the grass to get the paint off after :-)

[F Murtz]

Or mow it.

[Chris J Dixon]

Magic referees' foam?

Chris

[Reentrant]

Football referee's "vanishing spray"?

[Brian Gaff]

Well the laser idea is very similar to how the early cd players kept thier lens on course of course.

Brian

[mark]

Mow. Use coloured fertiliser.

mark

[mark]

Plan B:- Put a couple of bricks or a 'weight' onto the spreader to help wheel markings.

mark

[Harry Bloomfield]

Tim Lamb wrote on 24/09/2014 :

How about the Dam Busters idea?

Two straight vertical sticks mounted in a T shaped base. The top of the T keeps it at 90 deg, the vertical of the T has the sticks. Keep the two sticks in line and you follow a fairly straight path, then move it over by the widdth of the thingummy after each run.

[Tim Lamb]

In message , Harry Bloomfield writes

I thought the Dam Busters idea was to determine the drop point when the

2 vertical pegs matched the towers on the dam? Intersecting lights to control the height.

Current plan is to use two sticks separated by string matching the spread width at each end and move them manually. Height doesn't matter as I won't need to run over them.

Walking straight depends on finding something in the background to align with the target marker. I think the *drag marker* would be most accurate but time is pressing:-)

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[Harry Bloomfield]

Tim Lamb explained :

True, but I was thinking along the lines of a simple visual method, as an alternative to something more complex. My more complex idea was to use laser pointers, directed along the ground, with a 45 deg mirror on the appliance, which you sight through - someone had more or less suggested that and it would be quite fiddly to set up.

[Nightjar]

I'm not sure you want to look at the output from a laser pointer, but it should be fairly simple to set one up so you can see where it strikes the spreader and, provided you keep that point constant, you will be following the laser beam.

[Tim Lamb]

Yes. As said above, tricky set up for more than one trip.

The job is done. Different light conditions, slightly more grass perhaps. For a smaller, rectangular lawn I found *circular* or *lands* in agricultural parlance to work. That way you are travelling the same direction as the last trip and can easily see the wheel marks.

I did wonder if polarised sun glasses would help but didn't try.

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