How to make your own PCB business card

Business cards are often used in business activities, but traditional paper business cards cannot attract the attention of the other party. This article FS Technology will teach you to make a beautiful and practical pcb business card, which will make you stand out from many competitors.

Homemade PCB Business Cards

What you will learn from this project:

  • The process of making a simple PCB business card
  • Learn the manufacturing process of high-end PCB business cards with NFC functionality

Required tools and skills

Essential tools:

  • Soldering Iron
  • Hot Air Rework Tool
  • Solder paste
  • Soldering flux
  • Solder wire
  • Tweezers
  • Cross-lock tweezers
  • PCB cleaner
  • Cotton swabs
  • Toothpicks
 

Optional tools:

  • Smoke exhauster
  • Ornate glass
  • Phone with NFC
  • NFC Chip 1kb
 

Required skills:

  • SMD soldering skills
 

Bill of Materials:

  • Printed Circuit Board
  • 220 nF capacitor
  • 47Ω resistor
  • LED
 

Simple printed circuit board business card

Making PCB schematics

We can use EasyEDA to draw PCB schematics, it has a built-in simulator for signal measurements. Also you can find the required circuit schematics of the PCB components in the EasyEDA library.

  • Import the desired pattern into layer 22 “bPlace” and it will appear on the silkscreen of the PCB, above the black solder mask.
  • Introduce light on layer 16 “Bottom” which will be seen as copper traces covered by black solder mask.
 

The schematic diagram of a simple PCB business card is relatively simple. Except for the USB connector, the components we use on the circuit board are all SMD parts. Even so, you still need to know how the PCB works because you need to sketch it on the file.

PCB Design

Because your personal information (name, phone, etc.) needs to be recorded at the top of the panel, you will need to customize part of the ground plane and enter the information you need to display on layer 29 “tStop”. This layer is the solder mask that controls the top. Text overlays on the top and “tStop” layers can make your PCB business cards look better.

Precautions for Inductive Antennas

Radio waves cannot pass through the PCB board, so when designing the antenna, there must be no copper sheets above and below it. The correct way is as follows:

Correct Antenna Settings

When there is copper above the antenna, the ground plane of the PCB will block the reader, and energy cannot be transmitted between the NFC tag antennas, as shown in the following figure:

wrong antenna settings

PCB Layout

Before proceeding with PCB assembly, you need to understand the rules for the orientation of pcb components. To make your pcb business card more beautiful, you can place the components on the bottom of the pcb board and place the LED on the bulb filament. If you’re making an NFC-enabled business card, you’ll need to connect wires to the NFC IC.

Generate Gerber files

Gerber files are used by the PCB industry to describe PCB images. Gerber files are required whether you make your own PCB boards or outsource the fabrication to a professional turnkey PCB assembly company. After completing the schematic diagram, you can click the “Convert” button in EasyEDA to convert the schematic diagram into a PCB design. If you are using Eagle, you can export Gerber files from Eagle using the built-in CAM processor.

Order PCB board

If you want a high quality pcb business card, you can send your order to FS Technology, we have the most advanced equipment, the best technical team, the cheapest price. As a PCB manufacturing expert in China, we recommend the following designs for your board:
  • Number of layers: 2 layers
  • PCB thickness: 1.0mm
  • Size: 50*80mm
  • Surface Treatment: HASL
  • Copper Weight: 1oz
Ordered printed circuit board

Component installation

The PCBA board is to connect components through the lines on the bare board to achieve different functions, so PCB assembly is an essential work. For this, you need to solder the SMD components to the PCB board, then use the programmer to write the code into the microcontroller, and finally do the PCB assembly inspection.

Packaging PCB business cards

You can use foam double-sided tape to seal the edge of your assembled PCB board, print a mask, put it on the foam double-sided tape, cut off the excess, and complete a creative pcb business card.

PCB Business Card with NFC

Introduction to NFC Technology

What is NFC?

NFC is a contactless identification and interconnection technology (similar to Bluetooth PCB), its full name is Near Field Communication, which enables your mobile devices, consumer electronics to communicate within a range of < 10 cm. In recent years, popular mobile payment, identity authentication, transportation card recharge, etc. all rely on NFC.

How does NFC work?

The NFC working mode is divided into passive mode and active mode. This article only describes the active mode. Active mode means that when the signal sending device sends data to the target device, it must generate a radio frequency field, which can use the electromagnetic induction between the two loop antennas to charge the passive target (tag), as shown in the figure:
NFC schematic

NFC Chip Fabrication

Chip Requirements:

  • Small SMD package
  • Adequate storage capacity
  • Embedded Energy Harvesting Module

If you use a printed circuit board as a business card, the NFC chip is at its heart. The choice of the core can be varied, this article chooses NXP’s NTAG NT3H1101 IC. 

NTAG I2C is the latest passive TAG chip with I2C interface released by NXP, which is the agent of Dalian Dapinjia. It is widely used in household appliances, consumer electronics, wearable technology and home automation and other fields. It provides contactless and contact interfaces as shown:

NTAG I2C

Calculate Antenna Inductance

In order for the PCB business card to communicate and power, we need to add an antenna to the NFC tag. The antenna design of the NFC chip is relatively simple, as shown below:

Explanation of the icons in the picture above:

  • Voc: Magnetic field induced open circuit voltage
  • Ra: Equivalent resistance
  • La: Equivalent inductance
  • Rs: series equivalent resistance
  • Cs: Serial Equivalent Tuning Capacitance
 

When the transmitter senses a magnetic field, an open circuit voltage Voc appears at its terminals.

The sum of the series resistances Ra and Rs is the equivalent model of the circuit consisting of the NFC integrated circuit and its loop antenna, as shown in the following figure:

The NFC IC resistance Rs forms a resonance circuit RLC together with the antenna resistance Ra and the built-in capacitance Cs with the inductance La of the antenna.

The frequency formula of the resonant circuit RLC is shown in the figure:

 The formula for calculating the RLC of the resonant circuit

Resonant frequency formula noun explanation:

  • F: resonance frequency, unit: Hz
  • L: Equivalent inductance, unit: H
  • C: Equivalent capacitance, unit: F
L is an unknown parameter in this equation, and L needs to be calculated separately. The formula diagram is as follows:

Example: Assuming the frequency of NFC is 13.56 MHz an d the tuning capacitance is 50 pF, bring it into the formula to get the inductance L as:

Example diagram of inductance L

Rectangular Antenna Calculation

Only by obeying the geometric constraints, we can add a specific inductance antenna to the PCB board. Antennas with different geometries require different formulas to support. In order to facilitate the explanation, FS Technology uses a relatively simple rectangular antenna to design our PCB business card, as shown in the following figure:
Rectangular Antenna for PCB Business Cards

Explanation of the units in the diagram above:

  • A0 & B0: the overall size of the antenna
  • Aavg & Bavg: the average size of the antenna
  • T: track thickness
  • W: Track width
  • G: Gap between tracks
  • Nant: Number of turns
  • D: Equivalent diameter of the track
 
The formula for the equivalent inductance Lant is as follows:  
Equivalent inductance Lant
The interpretation of Lant’s formula is as follows:
Lant formula

Create Eagle Library

If you think designing the antenna is cumbersome, you can copy the rectangular open source antenna provided by NXP to design the antenna, and then change the position of the connector.

Design the Antenna

Soldering the NFC Chip

Soldering the PCB is a relatively important step. Whether it is before or after soldering, we need to do PCB cleaning. After cleaning is completed, flux needs to be prepared in advance. It can act as a temporary glue, apply it to the IC package with a toothpick, and when the two are aligned, use tweezers to hold the PCB components. Then get a new toothpick, take a small amount of solder paste, and place it on the pins of the component. Remember to control the amount of solder paste, overuse of solder paste is a common PCB problem and it can cause short circuits. Finally, use a hot air rework tool to melt the solder paste and solder the IC’s pins to the circuit tracks. To make the PCB business card more beautiful, you can use our pre-prepared soldering iron to remove the excess flux and make the Q-tip and isopropyl alcohol clean. Resistors and LEDs operate almost the same, so I won’t repeat them. Soldering the NFC IC by hand is the hardest step in this project, and the slightest mistake can lead to a short circuit. To this end, you can first master some skills of desoldering PCB components, even if you make mistakes, you can also reduce losses.

Program the NFC Chip

NFC Tools for Android: Find the settings menu on your Android phone and open the NFC settings.
iOS NFC Tool: The NFC tool of the iPhone will start automatically.
Launch the NFC tool, find the “Write” button, click “Add Record”, select “URL” as the record, enter the URL you want the NFC tool to transmit, click the “OK” button, and then enter the NFC tag on the “Write” page, When the dynamic icon is displayed, hold the phone close to the business card, the LED of the business card should light up at this time, when the icon shows “Writing completed, your NFC PCB business card is complete.
Knowledge and Precautions for Homemade PCB Business Cards

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