NFC business card 4 in 1 NfcCard-4in1

The Lichuang open source platform has many similar `NFC card' open source projects. After browsing, I felt inspired and put forward my own opinions. ![title_PCB_NFC_CARD.png] # Appearance, appearance* The first thing is appearance. Everyone is obsessed with appearance, but personally I feel that appearance is not that important. If you’re more advanced, design your own. If you’re lazy, just use a template. Personally, I prefer something concise. After all, you want to introduce yourself to others, so as not to be too vague and difficult to use. * The look of this open source design does not use templates to avoid commercial disputes. Simply use characters and graphics to piece together the appearance style, and you can modify it yourself after cloning it. * [Note] In the open source PCB, the three QR codes are still mine. Please remember to change them to your own after cloning. ![PCB_NFC_CARD_KEYSHOT.70.png] # Circuit* The circuit design is very simple, 4 NFC chips + induction coil, and the NFC chip is gated by a toggle switch. Adding a resistor and 4 LEDs can indicate which card is communicating when the card is swiped. ![BOM_4in1_NFC.png] # 4-in-1 functional design* After looking at other NFC cards in Lichuang, most designs can only weld one IC. I strongly reject this, because it is equivalent to replacing the access card with a PCB shell. It still takes up the space of a card, and the PCB is heavier and more inconvenient. * Other similar all-in-one designs, some use push buttons, and some use rotary dial switches, which all cause inconvenience in terms of size and operation method. * The 4-in-1 function of this design is realized by the 4-in-1 toggle switch with the material number `C2904918`, which is light, thin and convenient. The thickness of this switch is about 1.4mm. After being embedded in the PCB slot, it will only protrude by the height of a solder joint on the back. The front is almost flush with the 1mm PCB, and it feels very comfortable. Plus 4-in-1 function, one photo can hold 4 photos. ![4switch1.png] ![C722491511E46C4E1D12E6A515B65FDB.png] # NFC chip selection - COB packaging scheme refers to the NFC card on the Lichuang platform. There are generally two schemes for chip selection: * 1. Use NXP's `NT3H1101` , `NT3H1201` chip, large capacity, 1~2K bytes. But it only supports NFC tag function, and the price is slightly expensive, 2 to 3 yuan for a single chip. * 2. Low-cost COB packaged chip. You can choose to purchase `M1, UID, CUID, FUID, NTAG213/215/216` and other chips. There are many types to choose from and the price is affordable. Just buy the NTAG213 COB chip for NFC, which is enough to store general link information. Although 215 and 216 have large capacities, they are also slightly more expensive. (When making Animal Crossing丨Amiibo cards, it is recommended to buy 215 white cards directly, which saves trouble and is full in large quantities) # Cost* As a senior white prostitute party, cost accounting is more important than anything else, because the NFC using `COB package` The chip only requires a very low cost, with a unit price of about 4 or 5 cents. 4 ICs plus switches, plus LED resistors, excluding labor, the material cost is only `more than 2 yuan`. It's quite affordable and doesn't hurt to give it away. * I won’t post the purchase link for COB packaged TB. You can search for `213 chip COB` by yourself. The logistics company I bought from made me sick. The store had to make a profit from the actual shipping fee. He had the nerve to pay Baishi for the shipping fee of 10 yuan, but Baishi didn't care. Later, he inexplicably turned into Jitu. I waited for express delivery for 10 days. My own stores all ship SF Express in three levels on 10/12/14 according to the region. # Proofing and welding* The recommended prototyping thickness of PCB is 1mm. * After everyone purchases the COB chip, they can cut it by themselves. The welding effect picture is as follows. (The picture shows 1x UID chip + 3x NTAG213 chip) * The larger COB chip needs to be attached backwards, because the back side is metal and the front side will be short-circuited. * The four fixed feet of the toggle switch are slightly misaligned, but it's not a big problem. Just hook it up with solder. * When welding 4 LEDs, there is no need to distinguish between anode and cathode. What is induced in the coil is high-frequency alternating current, and the LED can be used in both positive and negative directions. ![D7574483BDB6AB35F89678B2C1C25AFF.png] ![1C31E0964F92338601EE625F900EB7E6_gai.jpg] The blue solder mask looks great as a business card. A 4-in-1 NFC business card for less than 3 yuan is really delicious. whee. #NTAG213 Programming* UID card programming will not be introduced here. I believe everyone is familiar with it. It is most commonly used for access control cards. * NTAG213/215/216 recommends using `NFC TagWriter by NXP_v4.8.6.apk` and `NFC Tools PRO.apk`. * `NFC TagWriter by NXP_v4.8.6.apk` can burn contact business cards, web links, WIFI network information, emails, geolocation, text and other information. But when I tested it, the `WIFI distribution network` burned in it could not be used. At this time, I can use another software. ![apk_ntag213_1.png] * For the process of writing WIFI network information, please refer to: [Zhihu: Use your mobile phone to make NFC tags that quickly connect to WiFi to achieve one-touch networking](https://zhuanlan.zhihu.com/p/143620449 ) * Both software are included in the attachment and are non-toxic and harmless. Remember to like and save the project. #Test* Because the card type depends on the COB chip mounted by yourself. Various M1 and UID are used for access control. NFC has many functions, so I won’t demonstrate them one by one. * Only one WIFI distribution network information is demonstrated here. After attaching it to the phone, click Connect to connect according to the WIFI name and password written previously. `It is always available at home. When guests come over, just scan the NFC tag to connect to your own WIFI, which is convenient and cool`. ![test20220301112932.png] # Like, Follow, Collect This practical 4-in-1 NFC business card can be DIYed by anyone with a handicap. It costs less than 3 yuan a piece, so hurry up and `Like, Follow, Collect` three times in a row. There will be more fresh open source designs in the future, so pay attention so you don’t get lost. * My CSDN blog: [CSDN blog](https://blog.csdn.net/mark_md/category_10794878.html) * My Github: [Github homepage](https://github.com/ZhiliangMa)