TagCube, 5x7LED dot matrix custom business card with NFC wireless power supply

To explain, NB means NFC is the Best (
 
Note for escape board)
NFC antenna parameters are related to board thickness. Please do not adjust the board thickness at will (it has been adjusted for 1.6mm). If you need to adjust, please use the official tool to recalculate the antenna parameters: NFC Antenna Tool, remember!
 
Board Introduction
The design of this board is inspired by the official demo of the LPC8N04 official development board (LPC8N04 Development Board for LPC8N04 MCU). The main changes are as follows:
The board is redesigned into a business card shape, divided into two sub-boards, NFC and debugging, of which the debugging sub-board can be removed when not in use.
For the convenience of wiring, the pins of the LEDs are re-modified, but it does not affect the function of the demo (the source code needs to be modified and the firmware recompiled).
The official design uses 35 LEDs to form a dot matrix. Here I directly use a large area of ​​5x7 LED dot matrix (usually used in elevators) for better display effect.
The LED matrix uses a replaceable design, leaving space for the use of crown springs or claw springs, and of course it can also be directly welded.
The multi-power supply design supports three power supply methods: USB, button battery and wireless power supply, which can be switched by a button switch.
More high-definition pictures of the board are shown below.
 
Demo usage method
The use of Demo is divided into two parts, namely MCU program download and App installation.
MCU program download is relatively simple. You only need to download the app_demo.hex file in the attachment to the MCU (the firmware is compatible with the two bootloader versions of LPC8N04). The burning method depends on the tools at hand, from the official MCUXpresso built-in tools to J-Link and the like.
For App installation, you need to download the corresponding Demo App on your mobile phone. For download and usage methods, see the User Manual for LPC8N04 Development Board, which will not be repeated here.
 
Accessories purchase suggestions
For accessories, the main one is the LED matrix. Of course, if you want to make a pluggable design of the LED matrix, you also need to use connectors such as crown springs and claw springs.
 
LED dot matrix
LED dot matrix needs to meet the following basic conditions:
common anode (7 positive and 5 negative), and the pin arrangement is as follows (the PCB leaves space below PIN8 and above PIN12, which is compatible with 7+7 design with two invalid pins) The size is about 39x54 mm2, and the height is generally 10 mm.
The pin spacing is 7.3 mm vertically and 22 mm horizontally.
If wireless power supply is required, only red and other LEDs with lower working voltage can be selected.
 
The purchase link is as follows:
https://item.taobao.com/item.htm?id=693466570477 (affordable price, only red, you need to choose a common anode, and confirm with the seller whether the existing LED dot matrix pins are compatible)
https://item.taobao.com/item.htm?id=12995093575 (the price is more expensive, there are three colors to choose from: red, blue and white, and all existing models are compatible) The
 
crown spring/claw spring
connector is quite expensive (after all, at least 12 are required), and is generally used for keyboard axes. If you buy here, please note that you need to choose 0.5mm through-hole. The options listed here are all compatible with the current PCB (hole inner diameter 1.04mm).
 
The purchase links are as follows:
https://item.taobao.com/item.htm?id=576197842803 (TS0.5Z through-hole, soldering required)
https://item.taobao.com/item.htm?id=559448570514 (MM0553, no soldering required)
 
Demonstration Video
The following two videos demonstrate the use of the demo, among which:
The first video demonstrates the display effect of the red and blue LED dot matrix, where the red LED dot matrix is ​​powered by a CR1225 button battery and the blue LED dot matrix is ​​powered by a USB-C interface.
The second video demonstrates NFC wireless power supply, which only uses the power provided by the mobile phone NFC to light up the LED dot matrix (the display effect is better in a dark environment).