How to Build the DIY RFID DOMINATOR 2.0 — A Complete Step-by-Step Assembly Guide
The RFID DOMINATOR 2.0 is an open-source, Arduino-based game timer designed specifically for team objective games like Airsoft and Paintball. It’s a physical “hill” (domination point) that tracks how long each team holds control using RFID bracelets or cards. The team with the longest cumulative control time at the end of the day wins — or in timed matches, the first team to reach a set target (e.g., 2 hours) takes the victory.
This fully DIY kit supports 2, 3, or even 4 teams (red, blue, yellow, green) and displays real-time scores on a 20×4 LCD in HH:MM:SS format (up to 99:59:59 per team).
Let’s build it!
What You’ll Need (Bill of Materials)
- Arduino Nano (or compatible clone)
- MFRC522 RFID module
- 20×4 LCD display with I2C backpack (2004A)
- Active/passive 5 V buzzer (7.62 mm or 5 mm pin spacing)
- 4× 5 mm LEDs (red, blue, yellow, green)
- Resistors: 3× 220 Ω + 1× 1 kΩ (THT)
- Pin headers (male + female, 90° where needed)
- M3 standoffs (10 mm and 6 mm) + nuts + screws (countersunk recommended)
- Custom PCB (Gerber files available on the project page)
- Optional but highly recommended: 3D-printed enclosure (124 × 123 × 48 mm, ~300 g assembled)
Total component cost: under €10 if ordered from China, €20–40 from local stores.
Step 1: Soldering Order & General Tips
Use a fine tip (≤ 2 mm) to avoid bridging pins. The PCB keeps the standard 2.54 mm pitch, so even beginners can solder it cleanly.
Step 2: LEDs, Buzzer, and Resistors
Insert the four LEDs (LD1–LD4) so their bodies sit flush with the PCB. Bend the anode/cathode legs slightly to keep them in place while soldering. Same technique for the THT resistors (R1, R2, R5, R6) and the buzzer (PZ1) — hold the buzzer with a finger while soldering from the back.
Step 3: Arduino Nano (MOD1)
Solder two 15-pin female headers on the top side of the PCB first. Insert the Arduino Nano from the bottom (USB port facing the direction shown on the silkscreen), then solder the headers while the Nano is plugged in. This guarantees perfect alignment.
Step 4: LCD Display with I2C Backpack (LCD1)
The LCD must already have its I2C module soldered on the back.
- Mount four 10 mm M3 standoffs on the PCB.
- Place the LCD on top of the standoffs and secure with M3 nuts from below and screws from above.
- Solder a 4-pin 90° female header onto the PCB that matches the height of your I2C backpack (adjust as needed).
- Plug the LCD’s I2C pins into the 90° header.
- Add secondary 6 mm standoffs on top — these will be used later to mount the whole board into the enclosure.
Pro tip: Different LCD modules have slightly different I2C backpack heights. Test-fit first.
Step 5: RFID Reader MFRC522 (MOD3)
- Insert an 8-pin female header into the PCB.
- Place the MFRC522 module on top and secure it with two M3 standoffs + screws/nuts.
- Only now solder both the module pins and the header — this prevents the reader from working itself loose over time.
The PCB holes are oversized on purpose because MFRC522 modules vary in mounting hole position between manufacturers. If you want rock-solid mounting, drill the two unused holes and add two extra 10 mm standoffs.
Step 6: Final Assembly into the 3D-Printed Enclosure
Use eight M3 countersunk screws (5–6 mm thread length recommended). Four screws go from the front into the LCD standoffs (make sure the LEDs slide perfectly into the light pipes!). Four more screws close the back cover.
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The enclosure has slots for a 25 mm-wide strap so you can attach the DOMINATOR to trees, barrels, or any object on the field. It’s designed for mini-USB, but micro-USB and USB-C cables also fit.
Fully assembled RFID DOMINATOR 2.0
Optional: Convert to Push-Button Version
Not a fan of RFID wristbands? Turn it into a classic push-button dominator in minutes:
- Skip the MFRC522 module entirely.
- Solder wires or screw terminals directly to the RFID header.
- Wire illuminated 16–24 mm push-buttons (I used low-profile PTEM 16 mm ones).
- Drill matching holes in the enclosure.
The button version works brilliantly in complete darkness thanks to the illuminated buttons.
Where to Get Everything
Full firmware, Gerber files for the PCB, 3D-printable enclosure, demo videos, and latest updates are available on the official project page:
https://your-iot.github.io/DOMINATOR/
Build one, take it to your next mil-sim or airsoft event, and watch teams fight like never before over that blinking box in the middle of the field.
Happy soldering — and may your team hold the hill the longest!
