Smart Bluetooth wireless circuit design using TC35I

Domestic expressways are developing rapidly, with highway grades improving and traffic mileage extending. However, the toll collection system of expressways has become a bottleneck in expressway development. At present, most of the expressway toll systems are still stuck in the parking toll mode where "change" is given based on the denomination of the banknote. For managers, it wastes manpower and material resources and increases operating costs; for consumers, it wastes valuable time and hinders efficient highway announcements. The GSM communication network has become very popular and has basically achieved seamless coverage in the country. The GSM wireless network system operates reliably and its encryption technology is very mature. Using the GSM network dedicated module TC35I, Bluetooth wireless data communication chip nRF401 and microprocessor for comprehensive development, the preliminary design and experiment of an intelligent toll collection system without toll stations and parking verification-free on highways were completed.

Wireless data communication circuits are mainly responsible for the short-range wireless data exchange between motor vehicles and fixed base station systems. It consists of core chip nRF401 and its accessory components. NRF401 is a dual-channel, high-performance, low-power dedicated wireless communication chip. The operating frequency is 433.93/434.33MHz, the operating voltage is 3.3V, and the maximum communication rate is 20kbps. It can be directly connected to the serial port of the microcontroller for asynchronous communication to achieve Data is sent and received without encoding the data. The data input terminal DIN is connected to the TXD terminal of the microcontroller, and the data output DOUT terminal is connected to the RXD terminal of the microcontroller. In this circuit, the communication rate is designed to be 19.2kbps. The circuit principle is shown in Figure 3.