Office plant monitoring

[Fat Fly]

I build moisture sensors from stainless wire. If this in pot at a depth of 1 inch domoticz reported 83% of moistre level.Real plant was dry and needed watering. I put moisture level on the soil

and sensor reported moisture level 43%. I test and put moisture sensor to the soil at depth 1 inch

Sensor reported moisture level 96%.

[carlierd]

Hello,

After several weeks I finally succeed to create a dedicated PCB ! It was started yesterday evening and works fine.

Some pictures:

Measure is reported each two hours. So I expect more than two years on a CR2032 (using @GertSanders firmware).

I can off course provide any information as PCB.

Thanks @mfalkvidd for the idea and the code. The project is now WAF ;)

David.

[Fat Fly]

Great. Nothing to say. But i need build this. 10 pcs first time. :) I live in farm or how to right say in english. With rubber boots from the land ?

[Lukács Attila]

Is it possible to purchase it somewhere? :)

[Fat Fly]

Why not mastered it self ?

[Fat Fly]

Yesterday my sensor reported moisture 80% but soil was very wet. Thoughts.

[mfalkvidd]

@Fat-Fly that is normal. Did you expect something else? If so, what did you expect?

[flopp]

@Fat-Fly
I have sensors that report 25-35% and they are still not dry.
I water for 10-20 min and they report 40%, sometimes 45%. But I know that when they report 25% it starts to be time to water.

[mfalkvidd]

@flopp the level reported will depend on the following things (maybe more):

• the pullup resistor - varies between different arduinos
• the soil composition - varies between different pots
• the temperature - varies throughout the day

That means it is impossible to compare readings from two different Arduinos in the same pot and it is impossible to compare readings from different pots using the same Arduino.

[flopp]

@mfalkvidd
Thanks

[Fat Fly]

From temp varies moisture level and from fertilizer too. At the bottom of the bucket was more. Yesterday i install moisture sensor to the greenhouse. Level was 60-70%. This is normal if i check with finger. :). Today i try drive relays and water pump.

[NetRap]

This sort of sensor is not good, because the electrolyticeffect.
You always should use soil sensors, which are based on the capacitive effect.

Like this one:
https://forum.mysensors.org/topic/4474/capacitive-soilsensor-for-measurement-the-humidity-of-flowers

Best regards,
NetRap

[Fat Fly]

My sensors is not good yes. I do not understand what is soil moisture % really. :( My pepper was overwatering. Very wet and moisture was 80% only.

[mfalkvidd]

@NetRap there are downsides but "no good" is incorrect. I have used these sensors successfully for almost a year.

[NetRap]

The problem is, that your design is based on conductivity.
This means, that the electrodes will be destroyed over time
and the produced metal salts are in your flower,garden,...

I don't will have metal salts in my tomatoes !!! ;-)

[mfalkvidd]

@NetRap I doubt that one second of 3V electric power every hour (0.03% duty cycle) will produce measurable amount of salt but yes, for food production capacitive measurements are probably better. The topic of this thread is "office plant monitoring" though and I hope you don't have to live off your office plants :)

[m26872]

"Metal salts" doesn't sound very dangerous unless you're more specific. I prefer some NaCl on my tomatoes.

How about some gold- or silver plated electrodes if you're of the worrying kind?

[Fat Fly]

I want to try electrodes from stainless steel.

[Lars65]

Normaly when you use eletricity and water, you need to sacrify something. For an example, when you cool a boat engine with water, you normaly use zinkanodes. I guess this is also the same when we want to messure humidity for an plant.
So, if you should use copper anodes for messuring, you could paint them with a zink color.
What it effects the resistance, I don't know.

[Fat Fly]

Maybe in scketch needed change measure time? Maybe need use function round ?