I tend to use the actual 7805's on the first board I solder up, because I don't care if I blow it up (CAN you blow up a 7805? they seem almost unkillable) and then put a switching reg in the rest of them as most of my designs are a 12-5v stepdown running around. Once I burn through them, my next revision will likely incorporate a more modern part footprint, or I will have a direct onboard Buck converter as opposed to a module. I've been using TO-220 footprint regulators because due to a long and boring story, I have ALOT of 7805's and probably a bakers dozen of the digital switching buck converters that occupy the same footprint. Otherwise cool project! BTW, clear heatshrink is a thing. Here's an option for the sensor (transmitter) side: I can't seem to find the TI appnote that I just read showing exactly this, but there's plenty of schematics online. Easiest way is just send it over a resistor more advanced is using an opamp or two to shift the 4mA down to 0V and output the full scale. The sensor produces 4-20mA based on it's reading, then at the MCU you convert the current back to a voltage to be read by the ADC. Just throwing this out there, a lot of industrial equipment uses 4-20mA output for sensors because it is more immune to noise/interference and won't be affected by long cable runs (which adds capacitance and inductance). I'm open to any and all feedback, thank you to this sub, and r/pcb for all the help! Here is some pictures of both sensors, and the control board I'm using them with. I performed several tests (one sensor wet, one sensor dry, reversed, etc) and readings remained consistent across the board. I didn't think they would have an impact on each other, but wanted to make sure each sensor didn't interfere with other sensors on the board. Neither sensor seems to impact the other. Mine responds almost instantly while the GikFun takes almost a full minute to go from "full dry" to "full wet" when submerged. My sensor responds much, much quicker to increasing moisture as compared to the GikFun. I'm hoping for a consisting impact on readings and have built RC filtering into the control board. I will also be performing tests with the 3 meter wiring harnesses attached to see what effect long wiring runs has on the analog sensor readings. I will re-test both once they have been conformal coated to see if that alters the readings. I assume this has to do with with my soil probe design (double sided on the PCB as opposed to single sided on the GikFun) or maybe because I'm using a "full power" 555 as opposed to the low voltage CMOS ones on the GikFun. The range is similar, but over a completely different set of voltage values. Not sure if I should de-solder them from non-test versions or not, open to feedback and also thinking of changing the LED so it only pulses when the sensor is being read somehow. If the LED light is still somewhat visible through the heat shrink I guess they will still be helpful although they do increase the total power draw of the system. I don't know if the LED light on mine is helpful, as a first run I wanted an "I'm alive" indicator but now that function is verified, These are going to be dipped in a conformal coating, have a ~3 meter wiring harness attached and have the electronic portion heat-shrinked for increased moisture resistance. My sensors are both narrower and shorter overall than the GikFun sensor. The soil probe portion however is almost the same length. I built my sensors much smaller than the GikFuns. My sensors respond at what seems to be the same speed for both. Interestingly, my sensors respond to going from dry to wet almost instantly while the GikFun sensors respond very, very slowly to increasing moisture (almost a full minute to go from "dry" to "wet" while submerged in water) but respond very quickly going from wet to dry. So I connected both a GikFun 2.0 Moisture sensor, as well as my sensor, to inputs 1 and 2 and tested both in air as well as submerged up to their "safe" level in a cup of water. If you want more details on the design of the sensor itself, go here: I posted an update on having received my first boards of my 555 timer based capacitive soil moisture sensor and had a chance to solder some JST-XH connectors on a panel last night and do some early testing.
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