- Mon Sep 10, 2018 10:01 am
#78173
Hello,
I'm new there, and this is my first post. I didn't find some topic to present myself in the different categories of this forum, as it usually the case, do forgive me if i have forgotten something, i don't want to be impolite.
Okay, so, i'm using an old wemos D1 R1 i still have at home, but anyway with an ESP8266 on it, to make some study about capacitive/resistive soil moitsure sensors .
At first i wanted to use only capactive sensors, because from what i've read they are lasting longer than resistive ones (corrosion).
So i have used a simple setup with only one capavitive soil sensor plugged to +5V, GND and A0 on the wemos. Then i have made some simple tests putting the sensor in water, air, dry soil, wet soil, very wet soil , and so. When i have seen that there was almost no difference between a very wet soil and water, i've decided to take 100% for this value and 0% for dry soil.
Then i have used ThingSpeak to send the value i'm measuring every minute. And results are surprising !!! Values oscillates between 50 and 7, it can be 50, then 70 next minute, and even if i make some median on it, humidty doesn't seem to decrease over time.
You can see that here between 7th and 9th of Sep :
https://thingspeak.com/channels/564209
Then i have made the same measures with a resistive sensor, and switched (on the same wemos) the sensor (just updating program to take into account the new min & max for wet & dry).
it seems that it works better (less random measures), but humidity is increasing instead of decreasing (probably linked to temp in soil). You can see it on the same graph from 10th of September.
If someone has an explanation for capacitive sensores, what am i doing wrong, i would be very interested
Thx for ur help
Cédric
I'm new there, and this is my first post. I didn't find some topic to present myself in the different categories of this forum, as it usually the case, do forgive me if i have forgotten something, i don't want to be impolite.
Okay, so, i'm using an old wemos D1 R1 i still have at home, but anyway with an ESP8266 on it, to make some study about capacitive/resistive soil moitsure sensors .
At first i wanted to use only capactive sensors, because from what i've read they are lasting longer than resistive ones (corrosion).
So i have used a simple setup with only one capavitive soil sensor plugged to +5V, GND and A0 on the wemos. Then i have made some simple tests putting the sensor in water, air, dry soil, wet soil, very wet soil , and so. When i have seen that there was almost no difference between a very wet soil and water, i've decided to take 100% for this value and 0% for dry soil.
Then i have used ThingSpeak to send the value i'm measuring every minute. And results are surprising !!! Values oscillates between 50 and 7, it can be 50, then 70 next minute, and even if i make some median on it, humidty doesn't seem to decrease over time.
You can see that here between 7th and 9th of Sep :
https://thingspeak.com/channels/564209
Then i have made the same measures with a resistive sensor, and switched (on the same wemos) the sensor (just updating program to take into account the new min & max for wet & dry).
it seems that it works better (less random measures), but humidity is increasing instead of decreasing (probably linked to temp in soil). You can see it on the same graph from 10th of September.
If someone has an explanation for capacitive sensores, what am i doing wrong, i would be very interested
Thx for ur help
Cédric
