08/16/07 A cheap trigger-on indictor for weed sensing sprayers

Farm and Ranch August 16, 2007 Intermittent spray systems that automatically spray only when weeds are present can reduce herbicide usage by 50-90 percent when compared to broadcast applications. And with the increase in no-till and chemical fallow in the region there is more of an interest in these weed sensing sprayers. But Mark Siemens with the Agricultural Research Service at Pendleton, Oregon says there is a drawback to this system when utilized on a wide boom sprayer. Siemens: "When you mount this units on a wide boom sprayer is that you can't determine from the tractor cab when an individual sensor unit is actively spraying." And that is important to know because the sensing units need to be recalibrated several times during the day due to changes in ambient light and field conditions. Siemens developed a simple solution. A trigger-on indicator. Siemens: "The cost of the simple circuit we developed, which only has four electronic components, is less than $20. Basically it is a visual indicator. It illuminates a super bright LED that is pointed back to the tractor cab." Siemens says about anybody can make the trigger and he has a list of parts and a circuit diagram. Siemens: "The long term solution would be for the manufacturer to provide some type of system that goes along with their commercially viable system." The units Siemens designed were put on a sensing sprayer and tested on 3000 acres of commercial farmland near Heppner, Oregon and the units performed reliably. I'm Bob Hoff and that's the Northwest Farm and Ranch Report on the Northwest Ag Information Network.