Special sensor

SWHY-28A Geomagnetic Vehicle detector

The working principle of SWHY-28A geomagnetic vehicle detector is a certain amount of disturbance will change the parameters when a metallic object approaching the magnetic field.

  • Model: SWHY-28A


The working principle of SWHY-28A geomagnetic vehicle detector is a certain amount of disturbance will change the parameters when a metallic object approaching the magnetic field. After a complicated data processing ,this detector judges the detection area occupied and departure of cars basing on the disturbance of the vehicle to the earth's inherent magnetic and use the sensor to inspect it.

SWHY-28A Geomagnetic vehicle detector will be widely used on side parking and flow measurements because of its compact size, easy installation and low damage to road property.


●The sensitivity and the testing period can be adjusted, to save the electricity consumption  and improve the working life on the premise of ensuring the accuracy rate.

●Correcting the data and automatic repetition system can ensure the information has been completely transmitted in complex and covered situation.

●Setting the switch detector’s parameters by phone App is much more convenient and easier to do the maintenance.

●Driving direction (forward or reverse driving direction) can be judged by a single detector.

●Have power-off protection function and  can recall the previous parameters when restarting the system.

●Low power warning function will benefit the future’s maintenance.


1. Geomagnetic vehicle detector can be used in pulling the car over project.

2. Geomagnetic vehicle detector can be used in flow metering on the crossroads.


Technical parameters






Inspection items


0~7 class


0~3m adjustable

Accuracy class


Sampling period

0~7 class

Networking scale

16384 receiver    address and each can manage mixmum 256pcs detectors


Radio frequency


Transmit power


Receiver data    transmission

Wired output

RS485 wired output

Wireless output

RS485 transmit    information to platform via GPRS

Working environment

Communicate distance

300m(no cover)

Working temperature


level of protection


1. This detector is a cylindrical product with a 90.5mm diameter and 88mm height. So please drill a hole a bit bigger than it on the ground, and sand the bottom flat, then inject the filler (usually use cloud gum), make sure that the upper edge is flush with the ground. We usually wrap one round tape on upper edge interface before shipping it out, which can prevent the top cover from sticking and can easy to change the battery.

Only need to unscrew the detector’s cover in anti-clockwise with a special tool when changing the battery.Sealing grease, fastening the upper cover and locking it after the battery’s replacement.

2. Installation of Electromagnetic receiver

Step 1:

Normally, Electromagnetic receiver connected with a four -core wires. when uploading data by wire ,the blue and the yellow are data lines (yellow is A, blue is B) while the red and the black are power lines (red is positive, black is negative).No special instruction for information uploaded by wireless.

If the receiver uses the four-core wires as the external power, 5~7V DC power supply is recommended.

If the solar panel & lithium battery mode is chosen for power supply, the four-core wire is directly connected with the solar panel. The red and the yellow of the power cord are positive as the black and the blue are negative. (Choosing 220V please consult with us)

Good quality mobile phones also can be used as the power supply in indoor laboratories. The receiver can’t share it with other equipment due to its great interference.

Step 2:

the detector is installed in the middle of the detected area.  Geomagnetic detectors should be covered in range of receiver’s circular communication as much as possible.

The receiver can be installed in a fixed pole such as a nearby lamp pole with a height of more than 3 meters after settling down the site.  The less shelter the better between the geomagnetic detector and the receiver.

Install the antenna after fixing the receiver, pay attention to identify GPRS antenna and geomagnetic antenna.

The antenna’s link port is on the top two sides of the receiver, with red protective cap. Please takes care of it.

Technological difficulties:

Firstly, since the Geomagnetic vehicle detector is driven by battery, so the power consumption directly determines the life of the product. How to control the power consumption is an important indicator and a difficulty to R&D team, our company has decades of years’ experience in traffic vehicle detection, we can extremely lower the consumption from both hardware circuit and software logic.

Secondly, the judgement and the handling of the vehicle’s signal is also very important, especially an unstable phenomenon show up cases like trailer car, high chassis car, minitype car, signal interference conditions.

Thirdly, the communication conditions between the geomagnetic detector and the receiver are very harsh. Most signals are sent and received on the detector in completely covered situation. So, the power of wireless transmission is directly related to the consumption. Only thousands of experiments’ debug can achieve the best balances parameter configuration.