Water level detection using probes ?

Hey experts

I am working on automatic water level controller. which consist of water flow switch based on reed switch mechanism. As water flow from that switch the current start flowing. now i am using relay to control the motor with flow switch.so now on the tank side i was thinking to use simple water probe
my friend suggested me to use 330 ohm resistor connected to 5v and other 330 ohm resistor to digitalpin as input.My tank height is long enough (around 8-10 ft) that i doubt that 5 v will not conduct from wire which led to dc losses ?.So guys i need your suggestion about detecting water. should i go to shop and buy float switch or i should make one as suggested by my friend ::slight_smile:

Regards Saif

Will the probes be in the water a very long time, consider the corrosion.
Nothing wrong with a float switch.
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LarryD:
Will the probes be in the water a very long time, consider the corrosion.
Nothing wrong with a float switch.
.

No as my tank is plastic so i think corrosion will not be an issue. but was thinking about dc losses due to wire?

Resistance in the wires would not be an issue.

Corrosion on the probe tips would be the concern, not the tank.
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I would make probe to transistor to Arduino interface.
But a magnetic float to reed switch might be desirable.

If you are just looking for a level detect, one method I have seen before was a LED/detector diode pair pointing down a round plastic rod. The end at the tank is cut to a wedge shape with 45 degree angles. What happens is the light goes down the rod, hits the two faces of the wedge and reflects back up again to the detector. If the end of the rod is in water, the index of refraction is close enough to the plastic that the two faces of the wedge no longer reflect the light and you can tell where the water level is (the two faces have to be polished so they do reflect). If you use the electrode in the tank, one method of dealing with corrosion is to use an ac signal to help prevent electrolysis. The Arduino has a fairly high impedance input, so it does not require much current to be able to sense the water if you use the probe method although I would suggest some signal conditioning on the input ( 100k resistor to the input with a 1ufd capacitor from the input to ground for example to protect from noise and limit any current on the pickup to safe levels). Any time you are working with external inputs to sensitive pins like on the Arduino, input protection is important so you don't have induced noise or static blowing the chip.

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1 Like

I like the bugs in the water - nice touch :slight_smile:

Corrosion. :wink:

saifkazi:
Hey experts

I am working on automatic water level controller. which consist of water flow switch based on reed switch mechanism. As water flow from that switch the current start flowing. now i am using relay to control the motor with flow switch.so now on the tank side i was thinking to use simple water probe
my friend suggested me to use 330 ohm resistor connected to 5v and other 330 ohm resistor to digitalpin as input.My tank height is long enough (around 8-10 ft) that i doubt that 5 v will not conduct from wire which led to dc losses ?.So guys i need your suggestion about detecting water. should i go to shop and buy float switch or i should make one as suggested by my friend ::slight_smile:

Regards Saif

You are some where right basically it depends upon resistivity of water which affects the conductivity between two wire probe.
But if you use plastic moulded ring type float switch it will work.

ive seen alot of people use the HC-SR04 to detect water levels, maybe an option

kau_cinta_ku:
ive seen alot of people use the HC-SR04 to detect water levels, maybe an option

This ultrasonic sensor will not detect large distance limitations only up to few cms.

See this pic of Reed switch type float switch.

images.jpg

mohit-singh:
This ultrasonic sensor will not detect large distance limitations only up to few cms.

Yes. Limited up to 2 meters for some, up to 3 Meters for some and up to 8 meters for the name brand. Not one of the waterproof ones can see closer than 25cm reliably

Of course you can mount it 25 cm from the top and see. Zero to 3meters from that point