CQRobot Contact Water/Liquid Level Sensor Compatible with Raspberry Pi/Arduino. for Automatic Irrigation Systems, Aquariums, Plants, in the Garden, in Agriculture etc.

I received this water level detector for free through Amazon Vine in exchange for an honest and unbiased review. This is a PCB with a water level sensor designed for use in embedded projects. The PCB has two switches that are not well documented: one switches the signal line between active-high and active-low, and the other allows the board to be powered at either 3.3 V or 5 V. It’s very basic — you either get a signal when water is present or you don’t. On the detection module there is a tiny adjustment screw, and after a few minor tweaks I was able to detect the water level in my plastic water jug. It won’t activate on metal, and if you touch it, it will trigger on your finger. A red LED on the detector shows when it has detected water, which is helpful during setup. Ideally, the detector pad needs to make contact with the side of whatever you are detecting. The pad is flexible and can be glued or zip-tied in place. The signal wire would typically be connected to a GPIO pin on an embedded device, but when powered at 3.3 V I found that this line only reached about 2 V. This is probably acceptable for most applications, but it should be considered when designing something that uses this detector. That said, it works well through glass or plastic and was perfect for measuring how much water is in my water butts in the garden.

💧 The box contains a single capacitive non-contact liquid level sensor with a short connector lead. The module is compact, clearly laid out, and arrives well protected. There is no printed documentation included, so I relied on the markings on the PCB and the product listing to confirm pin-out and switch positions. 💧 This sensor detects the presence of liquid at a fixed point and nothing more. It behaves like a simple on or off switch, triggering when liquid reaches the height where it is mounted. It does not report a graduated level, so monitoring multiple levels would require several sensors. In my case, I am using it to detect when a container is effectively empty, which suits this type of device well. 💧 Power and logic flexibility are handled by two small DIP switches on the board. One selects 3.3V or 5V operation, and the other inverts the output logic. I used it at 3.3V with an ESP32 without issue, and the single GPIO output keeps the wiring and code simple. Integration with ESPHome and Home Assistant was straightforward as the signal is just high or low. 💧 The sensor works on non-metallic containers such as plastic provided the wall thickness stays within the stated limits. It does not function on metal tanks. One of its main strengths is that it mounts externally and never contacts the liquid, which avoids corrosion and fouling. It is not waterproof, so outdoor use would require a protective housing, and thick garden water containers may push the limits of detection. 💧 With no moving parts, it should be suitable for continuous use, and so far it has behaved consistently. Long-term durability remains to be seen. At £15.99, it performs its job well and integrates cleanly with common microcontrollers, but for a single-point detection sensor it does feel expensive. It makes sense where non-contact sensing matters, though it is not a low-cost component. ✔️

This water level detector works great and it is very simple to setup. It features a very basic operation of on or off. This is great for controlling the set liquid level sensing weather for pump control or water level alarm systems. I have been using this with my raspberry pi 4 using home assistant to measure my rain water collection tanks and it was very easy to setup and use. This is a great quality sensor and perfect for any project needing water level automation. And for the price it's really excellent value for money to. I highly recommended it, thanks so much.

This non-contact liquid level sensor from CQRobot has been fantastic. I used it with Arduino for a few small projects and it works exactly as described. Setup was straightforward and it paired with my boards without any headaches. The non-contact detection makes it great for all kinds of liquids — no corrosion, no sticking — and it reads consistently in the 3–10 mm range I needed. In my use it’s been stable and accurate whether near water in an aquarium test or checking reservoirs in a small automated system. Build quality feels solid and it’s responsive without false triggers. If you’re doing DIY electronics involving liquid monitoring — especially with microcontrollers — this is a dependable sensor that’s worth the price.

First and foremost, I absolutely love how this water/liquid level sensor works with both the raspberry pi (including the latest raspberry pi 5) as well as the arduino. Hence it is perfect regardless of which one you have or want to use. Secondly, one of the biggest advantages of this sensor is that it is non-contact. This particular one is a capacitive sensor allowing you to measure water or liquid levels similar to how a touch screen works. Thirdly, and most importantly, it works perfectly! I have been using it for a month and it has proven to be both reliable and accurate. It is also fantastic value for money especially given the quality of this sensor! Overall, very happy with it! Would definitely recommend!

This is one of 3 non contact water detection devices by CQRobot that are electrically identical and differ only in the surface to which they are to be attached. This is the one intended for curved surfaces or pipes greater than 10mm in diameter. The sensor itself is pictured and requires a cable tie or similar (not supplied) to secure it to the pipe. A velcro tie supplied with the sensor to tidy the wires is unfortunately to wide to be repurposed. Other than that the device is excellent and makes implementing a trigger on absence/presence of water simple. I tested using a plastic water jug. The circuit board has a dip switch to select 5v or 3.3v compatibility and another to invert the output. Output is binary, 0v or high and doesn't float. For 3.3v input high is approx 2v, for 5v approx 4.3v. Rise/fall is smooth and doesn't require debounce although it might be wise to allow for air bubbles in the flow if rapid switching would be adverse for the application. Disappointingly none of this has any moisture protection. The video shows the electrical output on an oscilloscope when triggered. The device pulls about 3mA regardless of trigger state, sensitivity setting or input voltage. This is about as simple as attaching a device to your electronics project gets needing only physical installation, setting jumpers and connection for pwr, gnd, signal to pin then reading pin state. My only criticism would be the lack of moisture protection which if included would have made this perfect.

Bought for an Arduino project. Monitors a barrel and triggers a pump when level rises and of when drops. Was very pleasantly surprised by the operation of the sensor. Worked straight from the box.

This sensor does exactly what you’d expect. Hooked it up to an Arduino and it detected water levels without any fuss. The pins are solid and easy to connect, and the readings have been consistent so far. It’s pretty basic, but that’s all you need for simple projects like leak detection or monitoring a tank. The board feels decent quality, not flimsy, and it hasn’t corroded after a few tests in water. For the price, it’s a handy little component that works as advertised. Great for beginners or quick DIY setups. Happy with this.