Trying to find a water level sensor/switch

In summary, the conversation discusses finding a sensor for measuring water levels in a tank. The options considered include pressure sensors, pressure switches, and water level sensors. The conversation also touches on the importance of understanding the electrical output, the type of fluid being measured, and any environmental factors that may affect the sensor. One suggested sensor is the AquaPlumb water level sensor, which has been used successfully in an aquarium. A cheap alternative option is suggested to look for a level sensing switch in a junkyard.
  • #1
perplexabot
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Hello all. I am trying to find a sensor (probably switch is a better word) that will output a HIGH or LOW depending if the water (say, in a tank) has reached a certain level. I first googled: pressure sensor, then pressure switch. I also stumbled upon water level sensors, and now I am kind of confused.

I searched for some on amazon, this is what I found:
https://www.amazon.com/Amico-Aquarium-Liquid-Sensor-Stainless/dp/B006Z9691O/ref=sr_1_5?ie=UTF8&qid=1390023344&sr=8-5&keywords=water+level+switch
https://www.amazon.com/Amico-Liquid-Sensor-Horizontal-Switch/dp/B007Q85J7S/ref=pd_cp_hi_2

These contraptions don't make sense to me, I can only see two wires, GND and VIN, where is the output wire?

Any help will be appreciated. Thanks.
 
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  • #2
The switches have a single contact. You can connect the switch with a twisted pair of wires. One of those wires will be connected to ground, the other is the signal. If the signal is going to a micro-controller input then you will need a pull-up resistor or a programmed bias current on that input to make the voltage high when the sensor switch is open.
 
  • #4
The level sensors linked in the OP appear to have an external moving magnet and a fixed sealed magnetic reed switch. There are other methods of determining fluid level that do not have external moving parts in contact with the fluid.

To select an appropriate sensor requires knowledge of several of things.
1. What will the level sensor's electrical output be connected to ?
2. What fluid is the sensor being used to measure ?
3. What unusual environmental problems like waves, ice or cattle may be present ?
 
  • #5
Thank you for the great replies and sorry for my late one. So if my understanding is correct, the level switches in the OP only require a ground? The other wire is the signal? Also, the description of these switches say that the max switch voltage is 100V, I want to know how much voltage I need to supply it with (but then again, If my initial logic is correct, I only need to supply it with ground... Now i am really lost).

Baluncore said:
The level sensors linked in the OP appear to have an external moving magnet and a fixed sealed magnetic reed switch. There are other methods of determining fluid level that do not have external moving parts in contact with the fluid.

To select an appropriate sensor requires knowledge of several of things.
1. What will the level sensor's electrical output be connected to ?
2. What fluid is the sensor being used to measure ?
3. What unusual environmental problems like waves, ice or cattle may be present ?

I think first I need to find an appropriate switch then I need to figure out how it works. So first, as Baluncore has mentioned, a couple of things worth mentioning:

1. A micro controller (specifically a arduino nano)
2. Water (H2O)
3. None (a controlled environment... a water tank)
*. Outputs HIGH/LOW (not pressure value)
*. Low power (kind of obvious)
 
  • #6
Attach a twisted pair of wires to the two terminals on your float switch. At the Arduino, connect one wire to the digital ground. Connect the other wire to your Arduino logic input. Place a 10k resistor between the signal pin and +Vcc.

When the float switch contacts are open the input will be high, +5V. No power will be consumed.
When the float switch contacts are closed the input will be low, 0V. Half a milliwatt will be dissipated in the resistor.
 
  • #7
Baluncore said:
Attach a twisted pair of wires to the two terminals on your float switch. At the Arduino, connect one wire to the digital ground. Connect the other wire to your Arduino logic input. Place a 10k resistor between the signal pin and +Vcc.

When the float switch contacts are open the input will be high, +5V. No power will be consumed.
When the float switch contacts are closed the input will be low, 0V. Half a milliwatt will be dissipated in the resistor.

Ok that makes a lot of sense. Thank you.
 
  • #8
Hey perplexabot,

Although I personally am not as technically savy as some, I may know of a sensor that will help you. I have been using this water level sensor in my aquarium at home, and although I don't understand "how" it works, it seems to work pretty well, at least for my needs. It can actually tell me how much water is in the tank and shuts off the pump when the water reaches a certain level. Here's the link:
http://vegetronix.com/Products/AquaPlumb/
Hope this helps!
 
  • #9
JLodge said:
Hey perplexabot,

Although I personally am not as technically savy as some, I may know of a sensor that will help you. I have been using this water level sensor in my aquarium at home, and although I don't understand "how" it works, it seems to work pretty well, at least for my needs. It can actually tell me how much water is in the tank and shuts off the pump when the water reaches a certain level. Here's the link:
http://vegetronix.com/Products/AquaPlumb/
Hope this helps!

Hey, thanks for your help. I have actually finished this project a while back, I appreciate your input though.
 
  • #10
Note to next guy

go to a junkyard and look under the hood of any modestly fancy automobile. Find the "windshield washer fluid reservoir" , most of them have a level sensing switch to illuminate the "Low Wash" light on instrument cluster. Should cost you about a dollar.
 
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1. How does a water level sensor/switch work?

A water level sensor/switch works by using a probe or sensor to detect the presence of water. When the water reaches a predetermined level, the sensor triggers a switch to turn on or off. This switch can then be connected to an alarm, pump, or other device to control the water level.

2. What are the different types of water level sensors/switches?

There are several types of water level sensors/switches, including float switches, ultrasonic sensors, pressure sensors, and capacitive sensors. Each type uses a different method to detect the water level, so it is important to choose the right one for your specific needs.

3. How do I choose the right water level sensor/switch for my application?

Choosing the right water level sensor/switch depends on several factors, including the type of liquid being measured, the size of the container, the desired accuracy, and the required level of automation. It is important to consider all of these factors when selecting a water level sensor/switch to ensure it will work effectively for your application.

4. Can I use a water level sensor/switch in different types of liquids?

Yes, many water level sensors/switches can be used in different types of liquids, including water, oil, and chemicals. However, it is important to check the compatibility of the sensor with the specific liquid you will be measuring to ensure accurate readings.

5. Can a water level sensor/switch be used for both high and low water levels?

Some water level sensors/switches can be used for both high and low water levels, while others are designed for one specific range. It is important to check the specifications of the sensor to determine its range before use. Some sensors may also have adjustable settings to accommodate different water level ranges.

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