So is Seeed studio sensor Really Moisture sensor ? its Wiki saying it is a Soil moisture sensor But the Datasheet provided sth10 saying it is humidity sensor ?
is it gonna survive if put the sensor below two feet in the soil ?
And Can anyone tell me how to interface water mark soil moisture sensor to the arduino ? I did found this one http://www.emesystems.com/smx.htm.
Does anybody know how to make diy version of this?
I think the Seeed and the Watermark sensors are the same thing. The Watermark looks like it has a plastic housing of some sort, and lacks the heavy-duty cable. Look for reviews to see what people have said about their reliability, or buy one and bury it.
On the other hand, you could try taking a couple 2-foot lengths of insulated. copper wire, strip an inch or so at the end, tape them so the ends don't touch, and bury that. Test the resistance under varying watering conditions.
anilkunchalaece:
But I am Looking for one Actually I can use in Field...
Like stick in the ground/measure/remove?
I think you can't do that with cheap resistive sensors (your picture).
They need a resting rusting period.
And if you leave a circuit board in the ground, it won't last very long.
I think two 3" or 4" nails, 1" apart, is as good as those cheap resistive sensors.
I have a project going with two 3" nails permanently in the soil (potplant).
With an AC (not DC) measuring current.
Quite useable if you wait three days for the nails to settle (water frequently).
This resistive measuring method is somewhat temp dependent though.
No experience (yet) with capacitive sensors, like the chirp.
Seems ok for indoors (flower pots), but not for "in the field".
Too many exposed parts.
Attached is partially tested code if you want to experiment with "two nails in the ground".
You might have to play with the values (after three days).
Leo..
/*----Soil Moisture Sensor----
Two (galvanised) 3" nails, 1" apart
10k resistor from D5 to A0
47uF cap positive to A0 and negative to the first electrode
Second electrode connected to Arduino ground
Use twisted or shielded wire for long runs e.g. Cat-5
*/
const byte drivePin = 5,
samples = 25; // min one PWM period time | max 64 samples
unsigned long currentMillis,
previousMillis,
interval = 10; // sampling interval in minutes
int rawValue, // A/D reading
highPeak = 0, // start low
lowPeak = 1023, // start high
highValue = 240, // 100% dry
lowValue = 40, // 100% wet
dryValue; // dry value
byte moisture; // moisture percentage
void setup() {
pinMode(drivePin, OUTPUT);
analogWrite(drivePin, 128); // 1kHz square wave on pin 5
Serial.begin(9600);
Serial.print(F("Soil Moisture Sensor"));
Serial.print(F("\t Sample interval = "));
Serial.print(interval);
Serial.println(F(" minutes"));
Serial.println(F("===================="));
interval = interval * 60000; // change to millis
previousMillis = millis() - interval + 3000; // first reading after 3 seconds
}
void loop() {
currentMillis = millis(); // update
if (currentMillis > previousMillis + interval) {
for (int x = 0; x < samples; x++) {
rawValue = analogRead(A0);
if (rawValue > highPeak) { // detect highest peak
highPeak = rawValue;
}
if (rawValue < lowPeak) { // detect lowest peak
lowPeak = rawValue;
}
}
dryValue = highPeak - lowPeak; // calculate difference
highPeak = 0; // reset
lowPeak = 1023; // reset
previousMillis = currentMillis; // update
Serial.print(F("Raw="));
Serial.print(dryValue); // higher is drier
dryValue = constrain(dryValue, lowValue, highValue);
moisture = map(dryValue, highValue, lowValue, 0, 100); // invert and map to 0-100%
Serial.print(F("\t Soil moisture is ")); // higher is wetter
Serial.print(moisture);
Serial.println(F("%"));
}
}
anilkunchalaece: @Wawa
Thankyou for Reply..
I am looking for Which one of above sensor is best suitable for My Application
We still do not know your application.
water level at the surface will always be less than at depth after some settling.
it will always be higher after watering or rain.
most plant roots have a shallow depth, 2/3 meter deep is very deep for roots. that is if you are trying to use this for agriculture.
Consider that a simple enclosure on any of these will allow them to be burried.
you can dig a small well, put in stones, brick or pipe and place the soil sensor at depth.
make sure you make it air tight so there is no effect from the surface.
you can put on the end of a long probe and insert to depth. maybe need to 'drill' a hole so that insertion is easier.
It sounds like you are looking for something that will last. That means the cost will be high. Maybe 100-200USD. Take a look at SDI-12 sensors. They're what agriculture and environmental research usually use. Take a look at Decagon 5TM volumetric water content and temperature sensor.
Seems most of these expensive resistive sensors are the equivalent of "two nails in the ground".
The better ones with diurnal temp compensation.
OP is asking for DIY.
If this is for permanent deep soil, I would try two long evenly spaced stainless welding rods, or the sliding rods from an old flatbed scanner. Maybe embedded in gypsum. With e.g. a DS18B20 temp sensor.
The code from post#4 uses a ~1kHz square wave signal, sent to the sensor via a 10k resistor.
The sensor shorts part of this AC signal to ground via a cap (no corroding DC on the sensor).
Remaining peak/peak signal on the sensor is measured by an analogue pin.
Allan mentioned a high frequency. Not sure if that's needed for a simple setup.
Not a problem to change the drive pin to a higher frequency with code though.
Then the 47uF cap can be a lower value too.
Leo..
My main concern over using some bare metal probes is that once the OP is all done, measurement values will drift over time so the next student will look at the data and become confused. Are there any glass covered probe that are used as cheap alternatives?
liudr:
My main concern over using some bare metal probes is that once the OP is all done, measurement values will drift over time so the next student will look at the data and become confused. Are there any glass covered probe that are used as cheap alternatives?
calibration and testing will always be required.
for the use of sensors at depth, one might be well served to install a pipe and then insert said sensor at the base of the pipe.
that way one could use a seccondary probe to test and calibrate without having to dig up the sensor and disturb the soil.
as a note, capacitive sensors are not prone to decay from electrolosys, could be encapusulated to make an environmental shield and at 2 feet of depth, there would be less change of temperatures and effects of people would be reduced.
