Smart bracelets, as a more popular product form in the past two years, more and more attention, although it cannot be accepted by all, but its production, it does make changes in the electronic product market.
A smart bracelet is typically composed of a radio frequency circuit unit, a clock circuit unit, a memory circuit unit, a sensor circuit unit, and a master MCU unit, and the like, and the circuit PCB is typically concentrated in a smaller range, performing single or double-sided patchs. The board is 4 or 6 layers.
Since so many features are concentrated on a smaller PCB board, then in the layout and wiring of the bracelets, we must pay special attention, and now summarize some precautions for reference.
Figure smart bracelet PCB design
First, partition layout, pay attention to trace protection.
As can be seen from the PCB board above, various partial circuits (different color box markers) have a good partition: Since the smart bracelet is a collection of digital circuit components, as long as it is done in the circuit design. Supported resistors and capacitance distributions, you can complete a certain functional circuit module, thereby making circuit design more simple and easy to find. Although some sensor circuit units use analog circuit technology to perform data acquisition, once the module is designed as a module, the communication and information of the data can be completed by the corresponding connection interface.
At the time of the circuit module layout, it is necessary to pay attention to the clock circuit and the crystal circuit to reach the target tube. On the other hand, pay attention to avoiding the data cable when the clock is traveled, preventing the stability of the interference.
In the trace, it is necessary to protect the critical traces, such as whether the clock generating circuit, the crystal circuit, etc. are copper protection, whether to carry out loop protection, etc., generally protected in the design, and for the crystal oscillator part is required to dig copper treatment .
Second, deal with a radio frequency circuit.
The smart bracelet needs to link when using the phone, so the wireless radio portion is a key part, and in this partial design, it must pay special attention. Nowadays, smart bracelets are not more ivible based on Bluetooth-based wireless data transmission, so it focuses on Bluetooth RF processing. If the smart bracelet is only used for data transmission without the delivery of sound and music, then low-power Bluetooth is the best choice. When designing, the Bluetooth antenna shape, antenna layout, smart bracelet shell materials are affecting intelligence. An important factor in bracelet performance. A excellent radio antenna engineer is particularly important during the smart bracelet PCB design.
Again, do ESD protection.
In the previous article, I also wrote some technical and knowledge in circuit ESD. Today, I importantly tell the importance of ESD on smart bracelet products. Different countries and regions have different standards for different products or the same product ESD, in order to make the product through related tests, ESD protection design is required in design, and the ESD detection is required after design completion, ensuring that the product Adapt to electronic testing in the local market.
Finally, the system upgrade interface is reserved.
Is there an important significance for a functional upgrade of a smart bracelet for a fan or smart bracelet. If a product is upgraded in an appropriate time (may be the pre-hardware design to some features, in order to catch up with the market software, it is also possible to fix some software's bugs), which means that the product is still constant. During the R & D process, this is a good psychological compensation for users. Nowadays, the software upgrade of the smart bracelet usually has two methods: a method of transmitting wireless push through a USB interface. As for which method is used, it is necessary to determine the pre-planning and hardware planning.
Original link: https://www.eeboard.com/news/pcb-3/
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