Do you require a non-invasive method to measure liquid level, continuously from empty to full, in a plastic container or Bag? SMD Sensors is introducing our CQV Capacitive Level Sensor which offers a non-invasive solution that’s ready for rapid evaluation and integration. 

The sensor comes in contact with the outside surface of your vessel and may be press fit or adhered via PSA adhesive tape.  

To “test drive” the sensor’s capabilities, SMD Sensors offers the CQV Development KIT.  

CQV-DEV Capacitive Level Sensor Development Kit

Non-Invasive Liquid Level Sensor

What’s Inside the CQV-DEV Kit? 

Engineers will appreciate the completeness of the CQV-DEV kit. Out of the box, you’ll find: 

  • Four CQV1000 Flexible Sensors (Two with and two without adhesive backing) 
  • CQV8243 Control Box 
  • Plastic Demo Bottle 
  • USB Cable 

This kit is designed to let you start experimenting immediately, whether you’re prototyping in the lab or evaluating for production. 

Technology: How Does It Work? 

At the heart of the system is the CQV1000 flexible capacitive sensor. Unlike traditional float or optical sensors, the CQV sensor adheres to the outside of a non-metallic vessel, such as plastic or glass with no direct contact with the liquid. It detects changes in capacitance as the liquid level rises or falls, translating these variations into accurate, continuous level readings. 

 

Key technical highlights: 

 

  • Non-invasive: No risk of contamination or chemical compatibility issues. 
  • Flexible mounting: Sensors can conform to curved surfaces (minimum bend radius: 5/16”). 
  • Material compatibility: Works with vessels having a relative permittivity (dielectric constant) between 2.0 and 8.0. 
  • Fast response: Measurement updates as fast as every 50ms. 

Getting Up and Running 

Setup is straightforward and designed for rapid iteration: 

  1. Mount the Sensor: Attach a CQV1000 sensor to your vessel. For the best results, minimize air gaps or air bubbles between the vessel and the adhesive.
  2. Connect Hardware: Plug the sensor into the CQV8243 control box using the flat flex connector on the tail of the sensor. 
  3. Power Up: Use the included USB cable to power the control box. Alternatively, the device can be powered from a 5 to 24VDC external supply. 
  4. Connect to Your PC: Open your favorite serial terminal (e.g., PuTTY, Termite), set the communication settings as shown in Table X, and establish communication.
  5. Calibrate: With the vessel empty, type “ecal” to calibrate the empty state. Fill the vessel
    and type “fcal” to calibrate the full state.
  6. Start Measuring: Send the ASCII command “begin” to start streaming real-time level data.

Table X

Serial Communication Settings 
Baud Rate  115200 
Data Bits  8 
Parity  None 
Stop Bits  1 
Flow Control  None 

 

 

 

 

 

 

 

 

 

Data at Your Fingertips 

The control box outputs continuous level measurements as a percentage from 0 -100% via USB serial or I2C. Engineers can easily integrate the sensor into automation systems, data loggers, or custom control applications. 

USB Interface: 

  • Simple serial commands for calibration, data streaming, and configuration. 
  • Commands like info, version, help, and speed streamline setup and diagnostics. 

Refer to the user manual for a full list of commands. 

I2C Interface: 

  • 100 kHz bus speed, slave address 0x08. 
  • Structured data packets for seamless integration with embedded systems. 

Refer to the user manual for a full list of commands. 

Designed for Engineering Flexibility 

The CQV-DEV kit is built to accommodate a range of experimental setups: 

  • Flexible sensor options (adhesive and non-adhesive) 
  • Wide power supply range (USB or 5-24VDC) 
  • Robust connectors rated for hundereds of cycles 
  • Operating temperature: 0 – 60°C for sensors, -20 – 80°C for the control box 

Calibration: Precision at Every Step 

Calibration is handled via simple commands. The process stores calibration data onboard, ensuring repeatable accuracy even if the vessel or liquid properties change. 

Conclusion 

For engineers seeking a reliable, non-invasive liquid level measurement solution, the CQV Capacitive Level Sensor offers a robust, flexible, and easy-to-integrate platform.  

To get started, our CQV Development KIT allows your team to quickly evaluate this technology for your liquid type. Whether you’re developing for industrial, laboratory, or OEM applications, this kit provides the technical foundation for rapid prototyping and deployment. 

Ready to evaluate capacitive level sensing for your next project? The CQV-DEV kit is engineered to get you there quickly and accurately.