Water Level Sensors – Compatible Options

 

Our controller is designed to work with simple ON/OFF level sensors.
The controller does not measure water level directly — it reacts to a clean, isolated signal provided by an external sensor.

Two commonly used and fully supported sensor types are shown below.

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Option 1 – Float Switch (Mechanical Level Sensor - recommended)

 

How it works:
A float switch is a mechanical device that opens or closes an internal contact when the water reaches a set height.

 

Key characteristics:

• Provides a simple dry contact (ON/OFF)

• Very easy to understand and install

• Widely used in domestic and industrial water tanks

• Works independently of water quality

 

Typical use:

• Low level (start top-up)

• High level (stop top-up / safety cut-off)

 

Connection:
The float switch is connected to the controller via an opto-isolated input module, providing full electrical isolation between the tank sensor and the control electronics.

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Option 2 – Non-Contact Level Sensor (Capacitive, External Mount)

 

How it works:
A non-contact sensor detects the presence of water through a plastic tank wall, without touching the water itself.

 

Key characteristics:

• No moving parts

• No contact with water

• No tank penetration required

• Ideal for plastic tanks

 

Typical use:

• High level detection

• Overflow prevention

• Applications where drilling the tank is not desirable

 

Connection:
The sensor’s output signal is routed through an opto-isolated input module before entering the controller, ensuring electrical safety and noise immunity.

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Opto-Isolated Input Module (Signal Interface)

 

All external level sensors are connected to the controller using an opto-isolated input module.

 

Purpose of the module:

• Electrically isolates the controller from external wiring

• Protects the controller from voltage spikes and wiring faults

• Allows the use of sensors operating at different voltages (e.g. 12V or 24V)

• Improves reliability in electrically noisy environments

 

Important:
The opto-isolator is not a sensor.
It is a safety and interface component that ensures the controller only receives a clean, safe digital signal.

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Sensor Choice – What to Use?

 

The controller logic is compatible with all sensor types listed above.
The final sensor choice depends on installation preference:

• Float switch → simplest and most widely used

• Non-contact sensor → no water contact, no mechanical parts

The controller “brains” remain the same — only the sensor hardware changes.

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Safety and Reliability Philosophy

 

The control logic is based on:

• Separate LOW and HIGH level signals

• Time-limited filling (timeout protection)

• Fail-safe behaviour in case of sensor fault

This approach mirrors professional rainwater top-up systems while remaining DIY-friendly.