Modern life, people have become more and more attention to their own body health, and a good body can not be separated from the body of a variety of nutrients in a reasonable proportion. If the body of a substance content is too much, often may be due to the body of the endocrine disorders, and too much fat content will make the human body obese. The instrument to determine the content of various nutrients in the body is called a body fat scale.

Body fat scale on the small metal piece, in fact, is the electrode sheet. When we stand with our feet on both sides of the electrodes, there will be a weak electric current through the human body, the scale can determine the body fat content through the bioresistance resistance method (cell membrane resistance/capacitance to the electric current combined impedance model).

The working principle of the body fat scale with the BMS002 chip depends on the impedance detection capability of the BMS002 chip. This chip is a bio-signal SoC chip developed by Nanochap, which is capable of measuring and analyzing small signals at the biomolecular level, thus realizing an all-around health screening of the whole body and a "filtered" health detection of the biological activity and physiological function of various organs, tissues and systems.

Body fat scales containing the Nanochap BMS002 chip perform impedance detection by means of an electric current emitted by the chip:

• In low-frequency current passage, the cell membrane has a hindering effect on the current, the current will flow directly from the extracellular fluid, at this time, the human body shows the characteristics of resistance;

• In the passage of high-frequency current signals, the cell membrane will show the nature of capacitance, the current will pass through the entire biological cellular tissue, the human body reacts to the resistance, capacitance combined with each other in the complex impedance model.

• Based on the current signal and body weight, combined with the user's input of height, gender, and age, the body fat scale can calculate the content of fat, muscle, bone and other human body components through certain built-in algorithms, and this is how the body fat percentage is derived.

Nanochap Stim Engines Series BMS002 Biomolecular Signal Processing Chip Advantages and Features:

High detection accuracy: 16bits ADC, supports 40~2048 oversampling configuration.

High integration: integrated crotex-M0 core, 1~32K complex impedance detection circuit, built-in adjustable bias voltage micro-current detection circuit, support four-electrode current detection.

Multi-detection type: can detect blood glucose, lactate, uric acid, bilirubin, electrolyte, creatinine, cholesterol, ketone body and other biomolecular signals.

Product Parameters 

Supply voltage: 1.35V-1.65V

Communication interface: UART

Debugging interface: SWD

Package: QFN32 4mm×4mm

Current detection

Number of electrodes: 4

ADC precision: 16bits

Detectable parameters: lactate, uric acid, glucose, electrolytes, bilirubin, creatinine, ketone bodies, cholesterol, other trace parameters

Impedance detection

ADC: 250KSPS,10bits

Impedance range: 1-300kΩ

Impedance phase range:-90° - 90°

Application Scenarios:

Impedance measurement, medical/industrial biomolecular sensors, DNA/RNA/miRNA/protein detection, peptide/enzyme/metabolite detection, biomarker detection