Why transmission range of Bluetooth module fluctuates

The application of Bluetooth modules is very common in daily life, because Bluetooth modules are not only low-cost, short development cycle time, adaptability and scalability are very strong. However, we sometimes encounter some problems, such as the short distance between the Bluetooth module in communication and the situation where the data signal transmission fluctuates. Why is this?

1.Why is the transmit distance of the Bluetooth module short and fluctuates?

Frequency band: The lower the frequency, the longer the transmission range, but the lower the applicable data rate, so you must choose by yourself.

Signal strength: The higher the signal strength, the greater the probability that the data signal is transmitted to a longer distance, and the longer the reasonable transmission range; but the higher power consumption.

Receiver sensitivity: The signal receiver sensitivity of the machine equipment required by the Bluetooth of the mobile phone must be at least -70dBm to -82dBm; the larger the negative value, the longer the transmission distance, such as our BLM-KTB522’s sensitivity is -96dBm.

Unstable: check if the surrounding environment is affected by the same frequency, and whether wireless module is covered by a metal shield. Check whether the switching power supply system is good and whether the wave index of the switching power supply is small. Wireless communication products have relatively high requirements for switching power supplies and require smaller wave patterns. The vast majority of customers have communication abnormalities due to this reason.

2.There is an error in the communication received data

First, check whether the pulse signal socket of the control module is consistent with the connected equipment. Secondly, check whether the basic parameters of the serial communication of the control module are paired with the connected equipment. Finally, see if the control module api interface is not good.

3. No communication between 2 wireless modules

First, check the socket, whether the switching power supply is connected incorrectly, and whether the mobile phone charging cable is connected properly, you can analyze it according to the status of the indicator light.

Secondly, check whether the frequency, wireless channel and overhead speed of each control module are set, and you can check according to the PC equipped with mobile phone software. In the end, if the above process still fails to solve the difficulties, replace the sending control module or the receiving control module to see if the control module is damaged. The probability of damage to bluetooth module is not high, and the goods will go through several inspections before the shipment.

In the end, we suggest that customers reduce the baud rate of the overhead serial port as far as possible under permitted conditions, because the baud rate of the overhead serial port is too high, which endangers the communication transmission distance.