A load cell is a device that converts a mass signal into a measurable electrical signal output. Load cells are classified into eight main categories based on their conversion method: photoelectric, hydraulic, electromagnetic, capacitive, magnetic pole changing, vibration, gyroscopic, and resistance strain gauge load cells. Currently, the resistance strain gauge load cell is the most widely used type.
Resistance strain gauge force sensors in robotic applications
We know that load cells are a type of mechanical sensor. Depending on the method of force detection, mechanical sensors can be divided into strain gauge type, piezoelectric element type, differential transformer type, and capacitive displacement gauge type. Among these, the vast majority of weighing products use resistance strain gauge mechanical sensors, and most commercially available force sensors are of this type. Resistance strain gauge force sensors work on the principle that the resistance of a strain gauge changes as it deforms. They mainly consist of four parts: an elastic element, a resistance strain gauge, a measuring circuit, and a transmission cable. Specifically, by utilizing the phenomenon that the resistance of a metal increases when stretched, the strain gauge is attached in the direction of the applied force, and the change in resistance can be detected by the output voltage. The strain of the specimen is converted into a change in the resistance of the strain gauge, which is usually very small. There are various measuring circuits; the Wheatstone bridge circuit is commonly used. Load cells are used in container weighing management systems.
Classification and Application of Resistance Strain Gauge Load Cells
Resistance strain gauge load cells have a relatively simple structure, high accuracy, wide applicability, and can be used in relatively harsh environments. Therefore, they have found wide application. Currently, there are significant differences between the old and new national standards regarding the basic concepts and evaluation methods for the main technical indicators of load cells. They mainly come in several styles, including S-type, cantilever type, spoke type, plate ring type, diaphragm type, bridge type, and cylindrical type.
Among them, the S-type load cell is a common type of sensor, mainly used to measure tension and compression between solids. It is also commonly referred to as a tension-compression load cell. Due to its S-shaped shape, it is conventionally called an S-type load cell. This type of sensor is made of alloy steel, with adhesive sealing and protection treatment. It is easy to install and convenient to use, and is suitable for electronic force measurement and weighing systems such as crane scales, batching scales, and modified scales.
For example, electronic scales using this type of tension-compression load cell have better accuracy, lower cost, and are less prone to damage compared to ordinary pressure sensors, thus showing promising application prospects. This type of electronic scale can be used in factory production for material handling and force measurement, offering advantages such as accurate measurement, high resolution, durability, and low cost. Digital load cells are also used in electronic truck scale applications.
Digital weighing sensor
A digital load cell is a force-to-electrical conversion device that converts gravity into an electrical signal. It primarily refers to a new type of sensor that integrates a resistance strain gauge load cell, an electronic amplifier (AMC), an analog-to-digital converter (ADC), and a microprocessor (MCU). Currently, the development of digital load cells and digital metering instrument technology has gradually become a new favorite in the field of weighing technology, and its advantages, such as easy and efficient debugging and strong adaptability to field conditions, are making it stand out in this field.
In the era of the Internet of Things (IoT), sensors, modules, and gateways have become the three cornerstones of smart homes. Among them, sensors are increasingly deeply integrated with smart home systems. Various packaged sensor chips can be used to monitor environmental factors such as temperature, humidity, air pressure, and air quality. These sensor devices can be linked with home appliances in scenarios such as kitchens, bathrooms, doors, and windows to create intelligent home scenarios. It is foreseeable that the future market for smart home appliance sensors, including products such as smart air conditioners, smart range hoods, smart refrigerators, and smart air purifiers, will be very promising. Sensors have become one of the three cornerstones of smart homes.
Overview of the International and Domestic Smart Furniture Market
According to recent forecasts from international research firm IDC, the global smart home device market will grow to nearly 1.3 billion devices by 2022, with an annual growth rate of 20.8% over the next five years. Meanwhile, a report on the market prospects and investment of China's smart home device industry indicates that the Chinese smart home market will expand to 357.6 billion yuan by 2020.
On May 16th, at the Smart Home Sensor Ecosystem Summit held in Shenzhen, the "2019 Smart Home Sensor Ecosystem Development White Paper" was released. The white paper interprets the current application status and development trends of smart sensors in domestic homes.
The white paper points out that in China, the demand for smart home applications, primarily environmental and security sensors, is becoming increasingly prominent. These sensors mainly include temperature and humidity sensors, gas sensors, particulate matter sensors, infrared sensors, sound sensors, door and window magnetic switch sensors, and smoke sensors. Various smart sensors play a crucial role in enhancing the intelligence level of related application scenarios such as air purification, home security, and smart lighting.
Currently, commonly used sensors in smart homes mainly include the following: a certain temperature and humidity sensor.
1. Temperature and humidity sensor
Temperature and humidity sensors can detect the temperature and humidity in the air through special detection devices, and convert them into electrical signals or other required forms of information output according to certain rules.
Its applications are numerous; temperature and humidity sensors are used wherever temperature changes and water vapor content in gases need to be monitored. It not only relates to the quality of the home environment but is also closely linked to human health, making it a crucial component of smart homes. It can typically be used to control air conditioners, air purifiers, and so on. (Diagram of a gas alarm installation)
2. Gas sensor
A gas sensor is a device that converts information such as the composition and concentration of a gas into data that can be used by people, instruments, and computers. It is also an important detection method for smart homes. In daily life, combustible gases and pollutants are significant factors affecting people's health.
In smart homes, gas sensors can analyze hazardous gases, enabling targeted control strategies. This is a crucial step in protecting family safety and preventing danger before it occurs. These sensors, such as combustible gas sensors and carbon dioxide sensors, are typically placed in the kitchen.
3. Infrared sensor
Infrared sensors are measurement systems that use infrared light as the medium. They primarily function through the physical effects resulting from the interaction between infrared radiation and matter. In the smart home industry, they largely utilize the electrophysical effects of this interaction to control the on/off operation of electrical devices with infrared switches. Common infrared applications include infrared repeaters, infrared motion sensors, and door magnetic detectors.
4. Door magnetic sensor
Door magnetic sensors can be used to detect whether doors, windows, etc., have been illegally opened or moved. These sensors are typically installed on doors or windows to detect the opening and closing of doors and windows, and are used in conjunction with other smart security products to prevent dangerous intrusions.
It consists of two parts: a door magnetic sensor body and a permanent magnet. When the two are separated by a certain distance, the door magnetic sensor will transmit a radio signal to the system terminal to alarm. This sensor is also a very common sensor in smart homes.
