Simple Acupuncture Point Locator Circuit

An Acupuncture Point Locator Circuit is a device that helps in locating specific spots in the human body.

Thin needles are inserted into specific of the body parts so as to reduce pain in acupuncture which is an ancient medical practice.

Such special sites are referred to as acupuncture points or simply acupoints.

They are thought to have something to do with the movement of energy throughout the human body.

To locate these spots the Acupuncture Point Locator Circuit makes use of electronics.

Measuring the resistance of the skin is one method.

The resistance of acupuncture spots is generally lower than that of the surrounding skin.

A sensor that contacts the skin, a component that detects the signal and a speaker or light that switches ON when a point is detected can all be found in this circuit.

Circuit Working:

Parts List:

For this purpose the electronic acupuncture point locator circuit that is shown in this article makes use of a PLL IC CD 4046, a CMOS IC with an inbuilt voltage regulated oscillator (VCO).

The RC circuits R3 and C1 regulate the VCOs frequency range which is further affected by a control voltage.

Skin resistance R1 and P1 are used in a voltage divider circuit to generate this control voltage.

Both the frequency and the control voltage rise as skin resistance falls creating a signal that can be heard through the speaker.

It is the duty of transistor T1 to supply enough power to operate the speaker.

Formula:

Phase locked loop PLL integrated circuits like the IC 4046 are helpful in many different kinds of applications including FM demodulation circuits and frequency generators.

An Acupuncture Point Locator often uses the IC 4046 in a specific setup to identify changes in skin resistance or impedance at acupuncture points.

The basic function of an Acupuncture Point Locator that uses the IC 4046 is to measure the frequency output of the VCO which changes depending on the impedance or resistance of the skin at acupuncture points.

The relationship between the frequency VCO fout and the skin impedance are found using the following formula:

f_out​ = f_0​ + k * R

where:

• f_out is the output frequency of the VCO.
• f₀​ is the base frequency of the VCO.
• k is a constant that depends on the circuit configuration and the IC 4046.
• R is the skin impedance.

A case study of an application:

Assemble:

The acupuncture points are connected to the electrodes of the probes

Measurement:

A frequency counter is used to find the frequency of the VCO output

Meaning:

Skin impedance variations at acupuncture sites are connected to variations in fout which show the presence of the acupuncture point.

The PLL characteristics of the IC 4046 provide a flexible source for creating an Acupuncture Point Locator by sensing variations in skin impedance at certain body locations.

The particular needs and desired usage of the Acupuncture Point Locator circuit decide its design and calibration techniques.

How to Build:

To build a Simple Acupuncture Point Locator Circuit following steps are needed for connection:

• Connect the CD 4046 IC to the breadboard.
• Connect pins 5 and 8 of CD 4046 to the ground.
• Connect pin 13,14 and 16 of CD 4046 to the positive supply.
• Connect pins 6 and7 to the 560pF capacitor.
• Connect pin 4 of CD 4046 to the base of transistor 2N2222
• Connect emitter of transistor 2N2222 to speaker through a potentiometer.
• Connect a 4.7μF capacitor across the supply.
• Connect 2 potentiometer in series between the probe and the positive line.

Testing:

• Turn ON the circuit and change potentiometer P1 until the speaker starts to make sound.
• This indicates the changes in skin resistance are being detected by the circuit.
• By properly placing the P1 and P2 potentiometers experiment with different skin resistance levels and monitor changes in the sounds frequency.

Take note:

Please take note that the instructions below are simple and for more details check the component datasheets.

When working with electrical circuits be careful and ensure that all connections are connected correctly to avoid component damage.

Conclusion:

While electronic acupuncture point locators circuit may be helpful tools for acupuncturists but one has to keep in mind that they cannot replace qualified and experienced acupuncturists.

Acupuncture is a challenging medical practice and several factors including the patients specific demands and the practitioners level of knowledge can affect how well a treatment works.

References:

Schematic diagram and map of acupuncture