RFID DOMINATION TIMER - Airsoft / Paintball via Arduino

DOMINATOR (also called DOMINATION Timer) is a device - a stopwatch for Airsoft sports, Paintball with a second resolution. The stopwatch uses an Arduino control microcontroller (Arduino Uno / Nano) or a separate chip (Atmel) AtMega328P, which controls the entire system logic. The stopwatch includes an LCD character display measuring 16x2 (16 characters x 2 lines), or 20x4, which shows the times of individual teams, which communicates with the Arduino via the I2C bus.

Entities in the RFID DOMINATOR project (with color resolution of entities - also in the text below):

There are 2 teams in the game - RED team and GRE team, which play against each other and occupy the point that is formed by this device - DOMINATOR. At the beginning of the game, the display shows the times for each team with an initial value of 00 hours, 00 minutes, 00 seconds. Each member of the team is equipped with a card, bracelet or key fob, which communicates on the frequency 13.56MHz with an RFID reader, if it is within range.

Keychains and bracelets can be color-coded (green, red according to team and function ...), which allows them to be distributed more efficiently to players, but also their archiving and storage. If the RED team scores a point, the team player attaches his card to the reader, thus occupying the point. This action triggers a buzzer that announces a change in the point. Then the RED team's LED at this station will light up and the display will start adding time for that team.

If the point is occupied by the GRE team and the card is attached to the reader by a member of this team, the buzzer sounds again, the LED of this team lights up, the time of the RED team is paused and the time of the GRE team that occupied the point is calculated. If the card / key fob is attached by the organizer (referee), both times are paused until one of the teams presents the card. This type of card is thus suitable for starting a break, but can also be used at the end of the game, when it is necessary to stop time to evaluate the game. There is a fourth type of card in the DOMINATOR system - the eraser, which pauses both times and resets them to the initial values ​​as after starting the DOMINATOR stopwatch. Used to restart the game, initialize a new game.

The project is suitable for Airsoft events, sports facilities, or Airsoft teams, which can build the equipment. The advantage of the DOMINATOR system is that the system can be cloned and create X points with the same configuration via machine code, which can be fought independently in the game, while the RFID cards will work fully on all DOMINATOR devices. The system is tested, functional, easy to maintain.

The NXP RC522 reader works at a frequency of 13.56MHz, registers RFID tags at approx. 3 centimeters (almost physical contact with the reader is required), compatible ISO / IEC 14443-A tag format. The given tag standard also includes ISIC, bus cards that function as NFC cards and can communicate their physical address - UID to a reader within range.

Project hardware - RFID DOMINATOR:

• Arduino Uno / Nano
• LCD character display 20x4
• I2C converter for LCD display
• RFID reader NXP RC522 (13.56MHz)
• ISO / IEC 14443-A standard keychains / cards / bracelets
• Buzzer
• 2x LED diodes (can be replaced by a relay for switching lights to 12 / 230V)

Principle of functionality on the hardware side:

The RC522 RFID reader communicates with the Arduino via the SPI bus. It reads the UID (identifier) ​​of RFID cards in range, forwards this identifier to Arduino, which executes the program logic. The reader responds to the distance of the chip about 3 cm from the antenna. Arduino compares the read card address in a multi-condition. In the event of a match with a group of cards, the Arduino applies digital states to the diodes that indicate the occupation of the point, the detector announces the change.

Logic is executed every 100ms (counting in tenths of a second), controlling the counting of both times. The time is sent via the I2C bus to the 20x4 character display, where it is plotted. The display lasts up to 30ms at I2C bus speed 100 kHz - Standard speed. Maximum time range that can be listed in the system: 99 hours, 59 minutes and 59 seconds, the power consumption of the device is at the level of 60 mA at 5V supply. Suitable to power via power bank, charger from a phone with USB output.

RFID DOMINATOR project designation:

The RFID DOMINATOR project is, in terms of its versatility, suitable for implementation in Airsoft actions, and with the possibility of cloning the firmware, it is possible to install X DOMINATORS in the game field, which can be played with identical RFID chips. DOMINATOR is also suitable for teams, sports facilities, which can use this device to expand the game modes offered for individual games. If RFID cards, bracelets or key fobs are color-coded, it is very easy and universally distributed to players based on their team. Their archiving is also simple.

The use of cards, bracelets or key rings is easy and can handle all ages. The RFID chip itself is protected in a plastic case, it does not mind dirt, water, does not require maintenance. It has no battery, the chip activates an RFID reader, which charges it with the electric field it sends. DOMINATOR is suitable for game modes with the same number of players in both teams, e.g. DOMINATION, Capture Point (more than one DOMINATOR can be used in the game). The use is mainly for sports Airsoft, Paintball games, but DOMINATOR can also be used for other sports activities, where it can be used (boat running, orienteering, etc.).

Demonstration of functionality - RFID DOMINATOR (Domination Timer) - how it works:

Printed circuit board - PCB

There is a PCB design for the project, which includes the use of an Arduino Nano board. The PCB is double-sided with overhangs and has a size of 100x105mm. PCBs can be manufactured in Slovakia, for example at the manufacturer PB Spoj, or in China - machine production from GERBER files. One of the most popular and cheapest manufacturers is: JLCPCB. GERBER files can be uploaded directly as an archive, while the PCB is visualized, the layers it records are automatically set, the dimensions of the PCB are set. Production takes 1-2 days. This manufacturer used to be famous for the action of producing 10 pieces of PCBs for $ 2.

Today JLCPCB allows you to produce 5 pieces of this PCB for RFID DOMINATOR for 6.96 €, 10 pieces for 10.16 €. Transport - the cheapest alternative is available for 7.44 € up to DHL with delivery in 3-5 working days, while the cost of transport is 23.16 €. JLCPCB will automatically apply a discount coupon of € 8 for shipping, which will be assigned to you after registration. Thus, with the cheapest shipping alternative with delivery within 25 days, this shipping is free with the first purchase. It is also possible to use other available manufacturers, for example: PCBWay, AllPCB, NextPCB, SeeedStudio, which have the technology for PCB production by machine method from GERBER files.

Pin headers in PCB design:

• 2x female pin-header 15-pin (for Arduino Nano)
• 1x female pin-header 8-pin (for RFID reader RC522)
• 1x female 90 ° pin-header 4-pin (for I2C LCD display converter 20x4)

Spacers in PCB design:

• 4x spacer for character LCD display 20x4 (Ø max 2.5 mm)
• 2x spacer for RFID RC522 (Ø max 3.5 mm)

A PDF document with part dimensions is available on the Github:

https://github.com/martinius96/Airsoft-DOMINATOR-RFID/blob/master/docs/pdf/Rozmery_SUCIASTOK.pdf

Wiring diagram - RFID DOMINATOR

Program for reading UID addresses of RFID cards for DOMINATOR

The program is used to read identifiers (UID) of RFID tags, cards that will be used in the program for RFID DOMINATOR This source code does not represent RFID DOMINATOR! The card address is listed in the serial (UART) monitor - the used speed is 9600 baud / s. The statement should be saved and overwritten in a clear .xls (EXCEL) document, which will facilitate the management of assigned RFID cards to specific teams and entities. To successfully upload the source code for loading UID cards, you must import the MFRC522 library into your Arduino IDE.

Download the RFID DOMINATOR project repository (referenced by the first link at the top of the page), copy the contents of the /src/ folder (MFRC522 folder) to the /Arduino/libraries/ folder (the path to the folder depends on where you have the Arduino IDE installed), most commonly in Documents / Program Files on older Windows operating systems.

MFRC522 library in the Github project repository: https://github.com/martinius96/Airsoft-DOMINATOR-RFID/tree/master/src/MFRC522

The program is available in the Github project repository:

https://github.com/martinius96/Airsoft-DOMINATOR-RFID/blob/master/examples/GET_UID/GET_UID.ino

Example of stored UID RFID cards - Excel document .xls:

Software implementation for RFID DOMINATOR:

The recorded UID card data from the previous program for the RED, GRE, Referee and Eraser teams is entered into fields that can be easily scaled to expand the number of players. A simple cycle verifies in the program logic whether the card code is recorded in the relevant field. In case of a match, the logic is executed (output control, display update, setting of variables for system operation, etc.).

As keychains can also be bought in different colors, it is also easier to distribute them to team members during the game. RC522 RFID readers are most often sold with firmware version 2.0 (0x92), but there are also fake NXP RC522 chips that report address 0x12, but work normally with the MFRC522 library.

More about the RFID DOMINATOR project, the button and WiFi variant of the project can be found on the project website: https://martinius96.github.io/Airsoft-DOMINATOR-RFID/en

If you are interested in the software implementation of RFID DOMINATOR, please contact me in english language at: martinius96@gmail.com