Hi bidrohini.bidrohini,

No, I am sure nothing like that happened. Conditions were stable.

Best regards

torben

Hi Jenna,As far as I can see you start to have some fluctuations in the beginning. Then it drops from 510 to 490 rather fast when you water and then stays stable for a long time after which it suddenly increases 5 points.I give the sensor 15 min. to stabilize before I take as a base reading the avg. of 10 readings. I then take readings until I get a value 3 above the base and I take that value as the point at which I should stop watering. I think I have taken reasonable precautions.Still, at one point the readings jump upwards 48 points - which throws the system off balance -  and a bit later the readings drop 48 points.The difference between watering and stop watering (10 points) is chosen arbitrarily in order to get experience.

You see what bothers me: The instability of the sensor - if the problem is the sensor. But taking readings is such a simple thing.Best regardstorben

Hi bidrohini.bidrohini,

I did not touch the sensor while I took the readings.

Since I have done quite a few sequences and finally the sensor started perform normally - ie. slowly and steadily increasing the reading as the pot dried out.

That is worrying. Was there a fault in the sensor that disappeared or do sensors have to be “run in”?

Best regards

torben

Hi R2D2C3PO,

Here is a series of readings taken without first watering the system (approx. 3 min. interval):

For 8 hours the readings stayed at approx. 268

For 51 min the readings went from 268 to 279 

For 75  min the readings went from 279 to 266

when the system stopped. 

Best regards

torben

Hi Jenna and R2D2c3PO,I am sorry it took some time to come back.I have an indoor pot with earth (no flower) which I wet befor beginning to get a series of readings. I am sorry I could not see how to attach a file. I take a reading aprox. every 3 minutes over a period of approx. 15 hours. The readings vary between approx. 255 and 267 in waves.In Water I read 1 and in air I read 637. In earth I read approx. 255 corresponding to input 4,6 V and output 1.14 V.For readings I use Picaxe readadc10.I cannot figure out what is wrong - can it be a problem that there is no flower in the pot?

It is OK that the readings stay at about 255 for 3 hours - I assume that is the time it takes to get rid of excess water, but then the reading should start to climb steadily.

Can you help?Best regardstorben

Hi

I will be back.

torben

HI,

Actually, it started to climb again after a while.

Mystery!

Best regards

torben

Hi Jenna,

Thank you for your reply.

The DFROBOT's home page gives the following for DFROBOT SEN0308 (which is what I ordered from DigiKey):

Dry: 570-380

Wet: 380-290

Very wet: 290-0

That does not correspond to the  typical output voltages given by you.

The sensor I got from DigiKey is marked "Waterproof Capacitive Soil Moisture Sensor V.2.0” (and not DFROBOT SEN0308). I wonder if this is really a DFROBOT SEN 0308.

I am a bit confused - can you help?.

Best regards

Torben