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website/content/Hardware/1737993490702-Sensors&Pumps/index.md

@@ -3,13 +3,58 @@ title: "Sensors&Pumps"
 date: 2025-01-27
 draft: false
 description: "a description"
-tags: ["example", "tag"]
+tags: ["sensor"]
 ---
- an example to get you started
-# This is a heading
-## This is a subheading
-### This is a subsubheading
-#### This is a subsubsubheading
-This is a paragraph with **bold** and *italic* text.
-Check more at [Blowfish documentation](https://blowfish.page/)
-undefined
+# Sensors
+The board can address up to 16 sensors, with an A und B sensor per plant.
+The A sensor is always used, the B sensor is optional and use is suggested for larger planters.
+
+The sensor itself are just two spikes with a defined distance. They can be bought readymade or simply be done DIY with two long nails (use galvanized or non rusting ones)
+
+The Sensor is switched via multiplexer chips to a 555 oscilator circuit that uses he the earths resistance for charging and discharging a small capacitor. The ESP simply counts how often the charge pulse was seen. 
+While this sensor can be easily influenced since it runs in lower uA - mA range, due to the frequencys of several khz for normal moist plants, it is still very resistant, eg a 50hz failure signal from a nearbly power circuit would barely be registered.
+Since the Sensor is changing polarity between charging and discharging, corrosion due to organic battery effects is minimized, also it prevents errors due having build a battery (You can easily charge a planter to several V if you do not change polarity).
+
+# Pumps
+The board contains 8 low side switched pump outputs. The pumps are running directly from the battery without further voltage conversion, so ensure that the can survive the full voltage range of the battery.
+Each output can supply up to 3A continously.
+The board will never switch more than one output concurrently, so there is no need to size the battery for higher maximum load.
+An additinal extra out exists, that is switched, when any of the pump outputs is supposed to run.
+
+This allows for multiple possible setups
+## Layout Central Pump
+One central pump is connected to the extra output, and multiple magnetic valves are used for the different plants
+## Multi Gravity Feed Valves
+Per plant a Valve that can close against pressure is used, no pump exists
+## Multi Pump Setup
+Multiple smaller cheaper pumps with no shared hoses, so that failures will only affect a single planter.
+
+In any case I suggest to use a Water Filter on the Intake, as else you will get severe algae problems.
+
+In my personal opinion small membrane pumps are a really good fit
+* can be housed outside the tank 
+* require less maintance/cleaning
+* are able to pump smaller impurities without issues. 
+* Can pull water 1-2meters
+* Have higher output pressure -> Will blow out blockages in hoses
+However
+* are louder
+* pump less volume per time and energy
+
+{{< alert >}}
+DO NOT DIRECTLY CONNECT TO WATER MAINS, YOU HAVE BEEN WARNED!
+
+Software and Hardware may fail: It is your responsibility to ensure that a stuck valve or short circuit mosfet will not cause flooding and property destruction, for example by limiting the water tank to size that can drain.
+{{< /alert >}}
+
+
+# Todo
+## Flow Sensor
+There is a input for a flow sensor, currently it is not used as the software is missing. 
+* Allow monitoring if pumps are actually moving water
+* Allow to set limits for how much ml are allowed additinally to the current time limit per watering run
+
+
+
+Currently it cannot be set how two sensor should be interpreted and they are only averaged. More complex functions would be nice here, eg. allowing a user settable interpolation (0.8*a+0.2*b)/2 and Min(a,b) as well as max(a,b) 
+