This page is intended for internal use, as a blotter to remember what we have been up to.
May 2018 Project start Discussion of goals and actions. Primary goal : Build prototype UAV that can kill weeds using laser power. Actions : Lab experiments to find how much laser power is required to kill weeds. Look at alternative destruction methods (radiant heat, hot water, steam, directed chemical 'bullets'). Build drone as delivery system. Drone with mirror on gimbal to reflect high-power laser based at ground station. Tethered drone with fibre-optic coupling carrying laser light. 18-May-2018 First flight tests suggest stability will be a problem for directing laser during flight (video). Idea : give the drone legs on which it can rest. Saves on flying resources, and gives stable platform. 25-June-2018 Added 1-metre-long legs to Zero High-one quadcopter, and flew in ~ 5m/s wind (video). Unstable. Wind and old, slow control systems part of the problem, but need to make construction inherently more stable. Also tried lifting a garden hose, with and without flowing water, and that was surprisingly stable (video). 17-July-2018 Lifted pressure hose with hexacopter, worked well both with and without water, thought no high-pressure nozzle, and no gimbal. Tethered the tiny350 quad with 100m cables. Red 10mm2 0.2 Ohm total, White 6mm2 0.4 Ohm total. Flew, but lacked power. Calculated 10v loss over cables at 20 Amps. Can't compensate by upping source voltage, as the loss reduces when power drain drops, and the voltage at the drone would rise, frying the controllers. Couldn't get the GF1 to balance on the GF3 gimbal. Thought I'd got it before. New laserpointer too weak to see in grass in daylight. Batteries drained already ? No, new batts the same. 3v laser module also weaker than the distance meter, which is still our best laser source ! Increasing voltage to 4.5 doesn't make it brighter. The distance meter is rated as < 1mW too. Dec 2018 Video footage that we should try to take : 1) Drone stationery 1m up, laser on gimbal flitting around through smoke. Ideally flying, but may blow away smoke, so may need to be powered down on legs. 2) Drone 1-2m up, shooting out weed emulators. Alternate footage from distant camera with drone gimbal POV. Again, ideally flying, but probably not stable enough, so may need legs again. Maybe at least hop a bit. 3) B-roll footage of drone flying over crops, through smoke, slo-mo horizontal flight. 3-April-2019 Mark-II Weed emulators built (whole story here : The weedulators). 29 May 2019 Our guys on the national news : Aktuellt