Bluetooth smart express label design based on nRF52832

The application scenario of smart express labels in this graduation project is to be used with reusable smart express packaging boxes.

At present, companies such as JD.com and Suning have begun to use reusable express packaging boxes to transport specific goods. This repeatable express packaging box can effectively reduce the waste of express packaging. However, repeatedly pasting paper labels on reused express packaging boxes will reduce the service life and aesthetics of the express boxes.

Based on the above scenarios, this graduation project aims to design smart express labels that can be used in conjunction with them.

The following are the corresponding functional requirements of smart labels designed to match reusable smart express packaging boxes:

1. Label function

When the smart tag is at the receiving or dispatching end, it can be connected via Bluetooth via the courier's handheld mobile terminal to complete operations such as entering, modifying, and resetting express delivery information.

2. Low power consumption function

During the express delivery process, the smart label is in low power consumption mode (not shut down) and can receive specific external signals to wake up and enter normal working mode.

3. RFID identification function

By adding an RFID module, in theory, the RFID reader can be used to read and write the express transportation information when sorting at the express transfer station to achieve automatic sorting function.

4. Lock switch control function

Smart labels can switch on and off the mechanical locks of reusable express packaging boxes through buttons or mobile terminals. Ensure safety during express transportation.

5. Express location and tracking function

By equipping the smart label with a GPS positioning module, it can be used to track the precise location of express delivery in real time on a regular basis. On the one hand, it can prevent the loss of express delivery, and on the other hand, it can solve the current lack of express location information between stations during express delivery.

On the premise of the above functional requirements, the peripheral hardware was selected and configured for each function, and the corresponding circuit structure was designed, such as: 1. LDO voltage stabilizing circuit, which converts the input 5VDC to 3.3VDC to power the microcontroller 2 , Electronic lock drive circuit controls the electronic lock switch through GPIO, but the current is not large, so the NMOS field effect transistor is used as the drive component to design the drive circuit and realize the control function. 3. ADC measuring battery voltage circuit, using the method of resistor voltage division, an ADC measurement circuit is designed to measure the remaining battery power, which can obtain the remaining battery power information. ~~~~

The actual functional modules are as follows: GPS module: nRF52832 minimum system module: RFID radio frequency equipment module: OLED module with font: 5V regulated power supply lithium battery: 3-6V drive electronic lock:

The production and testing process of the principle prototype: The blank prototype board obtained by Jiali Chuang:

The principle prototype obtained after welding:

After functional testing, the principle prototype has been able to complete the expected functional requirements: 1. Modification of tag content through Bluetooth 2. Switching of low-power mode 3. Switch control of electronic locks 4. Acquisition of GPS information (because it needs to be outdoors Test, the test video was not captured)

Button 1: Read the courier information stored in the smart label, switch the OLED display, and display the recipient, sender information and remaining battery voltage information respectively. Button 2: Switch to low power consumption mode, switch off after entering low power consumption Turn on power to all peripherals, leaving only wake-up sensing. Button 3: Electronic lock switch button Button 4: GPS information reading and display (GPS signal needs to be obtained outdoors, the GPS module is not welded in the test video, but the longitude and latitude information can be obtained and analyzed normally by connecting the pin header to the GPS module)

LED4: Broadcast mode indicator light, it will flash during broadcasting and will stay on after connecting to the device.