Detecting fire alarm devices that interfere with smart lock signals of cars and motorbikes

The fire alarm device is using the 433 Mhz band, which is a common band for devices with conditions. The photo is for illustration purposes only.

A representative of the Radio Frequency Department ( Ministry of Information and Communications ) said that this is a smart fire alarm system with remote warning. Because the user bought an unsafe device, it broadcasts 24/7, causing interference with surrounding devices such as smart locks of nearby households.

After 5 days of interference, the neighboring households could not use the smart keys of motorbikes and cars, so they contacted the hotline of the Radio Frequency Department to report the source of interference. The Radio Frequency Department of Region 7 went to the site and discovered that the source of interference was a faulty fire alarm. This fire alarm had been used by the households here for 5 years, but it was recently faulty, causing the interference incident.

“The fire alarm device discovered in Binh Thuan has a low output power, so it only causes interference within a small range. To be able to detect interference within a small range, we need the cooperation of the people,” said a representative of the Radio Frequency Department.

According to the representative of the Radio Frequency Department, the control devices are in the Wifi frequency band, the frequency band reserved for driving devices... usually only used for a very short time to control the device. However, when it fails, it will continuously emit signals that interfere with other control devices such as smart locks of cars, motorbikes...

Fire alarm equipment is using the 433 Mhz band, which is a common band for devices with conditions. Control devices using this band have technical standards to control the output power so as not to affect other control devices. In addition, devices using this band must also comply with regulations on usage time so as not to affect the operation of other control devices.

'These control devices are used for only a short time of microseconds and the small transmission power will not affect other devices, such as car keys, motorbikes or rolling doors. Therefore, in the world, there are still devices using the same frequency band in medicine , scientific research, low-power control devices can still coexist. For example, a faulty smart lock device and continuous broadcast will affect smart lock devices of cars and motorbikes in the nearby area, but if it is not faulty, the surrounding devices will still operate normally. Previously, in Dong Tam ward, Hanoi, there was a faulty water pump control device that also continuously broadcast, causing interference for cars and motorbikes in that area and making it impossible to use the smart lock,' said a representative of the Frequency Department.

Recently, according to the reflection of people in the area of Vong - Nguyen An Ninh intersection, Hanoi, within a radius of about 100m, a strange phenomenon occurred when many vehicles and devices such as rolling doors, motorbikes, cars controlled by smartkeys could not operate. The Frequency Department then discovered that the remote control device to control the water pump was causing signal interference here.

The representative of the Regional Radio Frequency Center I also said that the above-mentioned interference device is of unknown origin, has no certification stamp, and has emission quality that does not meet the regulations on the frequency of 433.9 MHz/bandwidth of 37.5Khz. Therefore, it caused harmful interference on the frequency band for remote control devices to open and close car doors, motorbike locks... (433.05-434.79MHz) in the surrounding area. Afterwards, the working group of the Regional Radio Frequency Center I (Radio Frequency Department) together with PA06 and Dong Tam Ward Police handled and confiscated this device.

The representative of the Regional Radio Frequency Center 1 also said that the Radio Frequency Department has set up a hotline number 0862.92.92.92 to receive feedback from organizations and individuals when they discover smart car and motorbike locking devices and other cases of radio interference.

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