We want to know the moisture level across a .2 acre garden. For cost-effectiveness and simplicity, we're building multiple inexpensive sensors. The sensors blink at a moisture-dependent rate. A user visually inspects each sensor recording the blink rate and uses the data to determine the moisture level in the garden.
- [22 Sep 2010] We added moisture to Sample A during our experiment. Sample A has been marked as Sample A', and Sample B has been marked as Sample B'. Both samples will remain at Quelab for testing.
- [22 Sep 2010] sample A is blinking at 1 blink per 8 seconds. Sample B is not blinking.
- [22 Sep 2010] I took an A and B sample from the garden at Sunflower River. Sample A is from a dry part of the garden, Sample B is from a moist part of the garden. Visually, Sample B is more moist than Sample A.
- [Sep 2010] Testing with commercial soil from a planter outside of Quelab.
- [Aug 2010] Sunflower River and Quelab have started a project to test soil moisture levels in the garden at Sunflower River.
The current circuit we are working from, is this 1.5v flasher with the megaohm resistor in series with a simple soil sensor.
- need to invert the blink, so it blinks more when drier, far more intuitive, im thinking a resistor bypassing the BC557 might make it a comparator. But i'm totally not sure, very rusty on all this!
- May also need a wheatstone bridge for calibration/sensitivity adjustments
- Need to source sources for fabricating the circuit board cheaply
- packaging, going to try and heatshrink a coke bottle. around a form, sofar my idea is to build sensor and circutry through a bottle cap leaving a shrunken bottle for weatherproofing/protecting the circuit/battery
- need a accurate small scale, so we can measure dirt, dry/wet to get moisture content
- Cast simple averaging sensors
- attach wires to 2 stainless steel screws.
- screw through plastic bottle cap(poking outwards, wires inside the bottle)
- insert screws into liquid plaster in a mold. let cure 24hours.
- Remove from mold and let dry in sun,