Smart bracelet, as nearly two years more popular product form, more and more people's attention, although can not be accepted by all, but its production, and indeed the electronic product market has produced some changes.

A smart bracelet is usually composed of RF circuit unit, clock circuit unit, memory circuit unit, sensor circuit unit and master MCU unit and so on, and circuit PCB is usually concentrated in a small range, single or double-sided patch, The circuit board is 4 or 6 layers. The picture below shows the circuit PCB for the 37 degree smart bracelet found on the network.
Smart Bracelet PCB Design Considerations _37 degrees Smart Bracelet Circuit PCB
Since so many functions are concentrated on a smaller PCB board, then in the bracelet layout and wiring we have to pay special attention, and now summarize some of the precautions for reference.

First, partition layout, pay attention to line protection.

From the above PCB circuit board can be seen, the smart hand ring of the various parts of the circuit (different color box marks) have a good partition: the smart ring is a combination of digital circuit components, in the circuit design as long as Supporting the resistance and capacitance distribution, you can complete a certain function of the circuit module, which makes the circuit design more concise and easy to find. Although some sensor circuit unit using analog circuit technology for data acquisition, once the module is designed as a module, then, through the corresponding connection interface to complete the data communication and information transmission.

In the circuit module layout, on the one hand need to pay attention to the clock circuit and crystal circuit to go through the shortest path to reach the target discipline, on the other hand, in the clock when the line should pay attention to avoid data lines to prevent interference affect the stability of the system.

In the alignment, the need to protect the key traces, such as the clock generation circuit, crystal circuit, etc. are copper protection, whether the protection of the ring, etc., generally in the design will be protected, for the crystal part of the need to dig copper The

Second, deal with the RF circuit.

Smart bracelet in use and mobile phone need to linkage, so the radio frequency part is a key part of this part of the design, we must pay special attention. Now the smart ring on the market are nothing more than Bluetooth-based wireless data transmission, so the focus on Bluetooth radio processing. If the smart bracelet is only used for data transmission without the need for sound and music transmission, then the low-power Bluetooth is the best choice, in the design, the Bluetooth antenna shape, antenna layout, smart bracelet shell material are affecting intelligence An important factor in the performance of the hand ring. In the smart bracelet PCB design process, a good RF antenna engineer is particularly important.

Again, do ESD protection.

In the previous article I also wrote some of the technical and knowledge of the ESD aspects of the circuit, and today it is important to say that ESD is important for the smart wrist ring products. Different countries and regions of different products or the same product ESD requirements have different standards, in order to make the product through the relevant testing, in the design of ESD protection design, after the completion of the design but also ESD testing to ensure that through the product To adapt to the local market of electronic testing.

Finally, reserve the system upgrade interface.

A smart bracelet function upgrade is convenient for the user or smart brackets fans have an important significance. If a product in the appropriate time to upgrade the software (may be pre-hardware design to some features and in order to catch up with the market software did not keep up, it may be to repair some of the software BUG), which shows the product is still kept R & D process, which for the user is a good psychological compensation. There are usually two ways to upgrade a smart bracelet: through the USB interface and the wireless push method. As for which method to use, the need for early planning and hardware and software planning is to be determined.