LED Arcade Buttons Wiring Guide: 5V vs 12V, Resistor Math & Daisy-Chain Diagrams

Installing LED-illuminated arcade buttons can elevate your arcade project with vibrant lights – but it also introduces some electrical wiring considerations. Should you power them with 5 volts or 12 volts? Do you need resistors to avoid burning out the LEDs? And how do you wire multiple button lights without a spaghetti mess of wires?

This LED Wiring Guide will walk you through all these questions. We’ll break down the difference between 5V and 12V LED buttons, show you how to calculate or choose the right resistor for your LEDs (with easy examples), and explain how to neatly daisy-chain wires for powering a bunch of buttons. Whether you’re wiring up a couple of coin button lights or a full panel of 20 glowing buttons, this guide will help you do it safely and cleanly. Let’s light it up!

Table of Contents

5V vs 12V LED Buttons: What’s the Difference?

Voltage Rating: LED arcade buttons typically come in two flavors:

5V LEDs – Meant to run on a 5-volt supply (e.g. the +5V from a USB encoder or the Raspberry Pi).
12V LEDs – Meant to run on a 12-volt supply (e.g. an arcade power supply or PC PSU 12V rail).

Importantly, the LED elements inside actually use around 2 to 3 volts (that’s the forward voltage range for most single LEDs, with red around 2.0V and blue/white up to ~3.2V). The rest of the rated voltage (5 or 12) is dropped by a resistor or circuit. In fact, a 12V LED button usually has a built-in resistor that’s larger than a 5V one, to drop the extra voltage and limit current. This means brightness is not inherently better at 12V – a 5V and 12V LED of the same type can be equally bright if the current through the LED is the same. The only difference is how they are wired to accommodate the source voltage.

Identifying What You Have: Check the product details or look at the LED module on your button:

Some LED buttons explicitly say “5V” or “12V”. If they came with your kit, the kit instructions often specify this.
Often, 5V LEDs are used in USB-powered encoder kits (since USB provides 5V). If your buttons plug into a USB zero-delay encoder, chances are they are 5V.
12V LEDs are common in real arcade cabinets (where a 12V power supply runs lights) or in automotive-style buttons. Sometimes the LED holder will have a marking or part number you can look up.
If in doubt, assume it’s 12V and use a resistor (it’s safer to under-drive an LED than over-drive it). Or use a multimeter to check the current draw at 5V to gauge if a resistor is present.

Mixing and Matching: What if you have 12V LEDs but only a 5V source available (or vice versa)?

Running a 12V LED on 5V: It will likely just be dim or not light fully. Because the internal resistor is sized for 12V, at 5V the current will be much lower (potentially too low to visibly glow). For example, one Reddit discussion noted that using a 12V LED on 5V will result in roughly half brightness – it won’t damage anything, it’s just under-powered.
Running a 5V LED on 12V: Do not do this without adding appropriate resistance! A 5V LED unit expects only 5V; if you give it 12V, it will draw too much current, likely overheat, or burn out almost instantly unless a suitable resistor is added to limit current. We’ll cover how to calculate that resistor next.

In short, stick to the intended voltage when possible. If you only have a 12V supply but 5V LEDs (or vice versa), treat it like using a bare LED – you’ll need to add or change resistors to make it work properly. Many button LEDs come with resistors pre-attached for convenience at their rated voltage (so you don’t have to think about it as long as you match the supply).

Why 5V vs 12V: One isn’t strictly “better” than the other; it depends on your setup:

5V Pros: Easily available from USB, no separate power supply needed if your system already has 5V. Safer (lower voltage to worry about shorting).
12V Pros: Allows chaining more LEDs in series (not typical for buttons, but relevant for LED strips or long runs in a cabinet marquee). If you already have a 12V source in your cab (like a PC PSU or JAMMA PSU), 12V buttons can tie into that. Also, running many LEDs on 12V can mean lower current on each wire (since voltage is higher, current is lower for same wattage).
For 99% of button lighting, 5V is easiest – especially with USB encoder builds. In fact, many zero-delay encoder boards have a 5V output header specifically for powering button LEDs.

Resistor Math Made Simple

Every LED needs a resistor (or some form of current limiting) in series to prevent it from drawing too much current and burning out. If your LED button didn’t come with a resistor built-in (or if you’re repurposing an LED from something else), you’ll need to add one.

Ohm’s Law Basics:

To choose the right resistor “R” for an LED, you can use this formula:

R = (Vsupply – VLED) / ILED)

Where:

Vsupply is the voltage of your power source (5V or 12V, for example).
VLED is the forward voltage drop of the LED (typically 2V for red, 3V for blue/white, etc.).
ILED is the desired current through the LED in amperes. For most small LEDs, 0.02 A (which is 20 mA) is a safe, bright value. You can go lower (10 mA) for longer life/dimmer output or if you have many LEDs to avoid drawing too much total current.

Let’s do a quick example for each common scenario:

5V supply, red LED (~2V drop), 20 mA:
R = (5V – 2V) / 0.02A = 3V / 0.02A = 150 Ω
So a 150 Ω resistor is ideal. The nearest common value is exactly 150 Ω. A slightly higher value (like 180 Ω) will make it a bit dimmer and safer.

5V supply, blue LED (~3V drop), 20 mA:
R = (5V – 3V) / 0.02A = 2V / 0.02A = 100 Ω
So 100 Ω works. To be safe (and because blue LEDs can be very bright), you might use 120 Ω or 150 Ω, which would lower the current to ~13–17 mA. Still bright, but gentler on the LED.

12V supply, generic LED (~2V drop), 20 mA:
R = (12V – 2V) / 0.02A = 10V / 0.02A = 500 Ω
You likely won’t find exactly 500 Ω, but 470 Ω or 560 Ω are common.

470 Ω → ~21 mA (a bit more current, still okay)
560 Ω → ~18 mA (a bit dimmer, also fine)
We used 560 Ω in one of our 12V tests and brightness was still very good.

12V supply, LED already designed for 12V:
Some LEDs (like “12V LED modules” or strips) already have a built-in resistor (often around 470 Ω). In that case, you can connect them directly to 12V.

At 5V, such a module will be very dim, since the resistor is too large for that voltage.
A “5V LED” module typically has a built-in ~150 Ω resistor. If you run it at 12V, you’d need to add about 330 Ω more in series (for a total of ~480 Ω) to avoid burning it out.

Resistor Power Rating: LEDs draw small currents, so a quarter-watt (0.25W) resistor is typically fine. Check the power: P=I2∗RP = I^2 * RP=I2∗R. Example: 20 mA through 150 Ω is 0.02^2 * 150 = 0.0004 * 150 = 0.06 W – well under 0.25W. Even 20 mA through 560 Ω is 0.224 W, still okay on a 1/4W resistor (though getting close, a 1/2W could run cooler in that scenario). Generally, any standard 1/4W resistor works for single LEDs at these currents.

Cheat Sheet Table: Here’s a quick reference for a single LED:

Supply Voltage	LED Color (V_drop)	Approx. Resistor (for ~15-20 mA)
5V	Red (2.0V)	150 Ω (for ~20 mA)
5V	Green (2.1V)	150 Ω ( ~19 mA )
5V	Blue/White (3.0V)	100 Ω (20 mA) or 120 Ω ( ~17 mA )
12V	Red (2.0V)	560 Ω ( ~18 mA ) or 510 Ω (~20 mA)
12V	Blue/White (3.0V)	470 Ω ( ~19 mA ) or 510 Ω (~17 mA)

If in doubt, err on using a slightly higher resistor. Your eyes likely won’t notice a small drop in brightness, and the LED will run cooler and last longer. And remember, these values assume one LED on its own. Some arcade buttons use two LEDs or an LED PCB – those might require different handling (e.g., if two LEDs are wired in parallel, treat each separately; if in series, the combined forward voltage changes, etc. – though most arcade buttons have just one LED or two in parallel for brightness).

Daisy-Chaining Wiring: Keeping It Tidy

When you have multiple LED buttons, wiring each one individually to the power source can become messy. Daisy-chaining is a technique to simplify the wiring by linking the common connections.

Understanding LED Terminals: An LED button usually has two terminals: a positive (+) and a negative (−). For simplicity:

Let’s call the +5V or +12V supply line “Power” (positive).
The 0V or ground line “Ground” (negative).

All your button LEDs need a connection to Power and Ground. Instead of running separate wires from each LED back to a single point, you can run one wire that hops from one LED to the next carrying the common node.

Daisy-Chaining Example (for Ground): Suppose you want to chain the ground connections:

You take a wire from the ground terminal of LED1 to the ground terminal of LED2, then from LED2 to LED3, and so on, and finally from the last LED to the ground point on your power source or encoder. This creates a single continuous ground line that touches all LEDs.
Many arcade kits provide a daisy-chain harness: it’s essentially one long wire with several quick-disconnect connectors along it. For instance, a harness might have 10 spade connectors crimped to one long wire – perfect for connecting to 10 button grounds in one chain.
You can do the same for the +5V side: chain one +5V wire across all the + terminals and connect one end to the +5V output on your board. In fact, some encoder boards expect you to do this: they have a single 5V pin and a provided daisy chain that goes to each button’s LED +.

Daisy-Chain in Practice: In a typical USB encoder kit (like the GeekPub Zero Delay board), the black wire harness is a +5V chain and the red wire harness is a Ground chain (though confusingly, the colors were reversed convention in their kit). The instructions might say: plug the chain’s first connector onto the board’s +5V pin, then connect each subsequent spade to each button’s LED + terminal. Then do the same with the ground chain from the board’s GND pin to each LED −.

You can also chain only one side and use individual wires for the other – it depends on your wiring layout. Chaining both + and − is essentially making a series loop which is not typical (LEDs should be in parallel, not series, with respect to the supply). Usually, you chain the common line that doesn’t need to be switched or individually controlled. For LEDs that are simply always on when powered, both the + and − are common, so either (or both) can be chained. If you had a situation where each LED’s + was individually controlled by a transistor or something, you’d chain ground.

Pros of Daisy-Chaining:

Fewer long wires running to a single point. It’s cleaner and uses less wire overall.
Easier troubleshooting: one continuous wire means fewer unique runs to come loose.
Looks nicer – you can route one chain around the buttons in order, instead of a star of wires.

Cons / Cautions:

If any link in the chain comes loose or breaks, all LEDs further down the chain will lose connection. For example, if the first connector from +5V slips off, none of the chained LEDs will get power. So make sure crimp connections are tight.
There’s a limit to how many you should chain in one string from a single source in terms of current. If you have many LEDs, the first section of wire carries the sum of current for all LEDs down the line. E.g., 10 LEDs at 20 mA each = 200 mA through the first segment. That’s fine for typical 22 AWG wire (can handle > a few amps), but be mindful if you had dozens of LEDs – you might split into two chains to distribute current.

Using a Terminal Block (Alternative): If you prefer not to chain, another neat method is to use a small screw terminal block or a “bus bar”. You connect the supply to the block, and then from that block run individual short wires to each LED. This achieves the same electrical result (all positives together, all grounds together) but in a star topology. It’s more wires overall but can be tidier if you have a spot to mount the block. Daisy-chaining tends to be simplest when an included harness is provided.

Step-by-Step: Wiring Your LED Buttons (Scenario: 5V buttons with Daisy-Chain)

Let’s put it all together in a practical wiring scenario – for example, you have a 1-player USB encoder and 6 LED buttons (5V type):

Plan the Circuit: All LED + terminals will go to the encoder’s 5V output, and all LED – terminals will go to the encoder’s GND. Since these are 5V LEDs, they likely have built-in resistors (check documentation; most kits do). If not, you’d wire a resistor in series with each LED’s + lead.
Prepare Daisy Chains: Use the provided harness or create one. For instance, take a wire long enough to reach all buttons in a loop. Crimp a connector for each LED on it (spade connector matching LED terminal). Do this for both the 5V line and ground line.
Connect to First Button: Take the 5V chain, connect its first connector to Button1’s +. Take the ground chain, connect first connector to Button1’s –.
Link the Rest: Continue by connecting Button2, 3, … with the subsequent connectors on each chain. You’ll end up with something looking like a ring linking all + together and another linking all – together.
Hook to Power Source: Attach the start of the +5V chain to your 5V output. On a USB encoder, this might be a pin labeled 5V or a screw terminal labeled +5. Attach the start of the ground chain to a GND pin on the encoder. If using a PC power supply or external adapter, you might crimp those to a molex connector or screw terminal (one wire to +5V, one to ground).
Double-Check Polarity: Remember, LEDs only light if connected correct way. Ensure the chain connected to all the + pins indeed goes to the +5V source, and the chain on – goes to ground. If you accidentally swap them, no damage (LED just won’t light), but it won’t work until fixed. Some kits confusingly wire red as ground and black as +5, so color isn’t always a guarantee – rely on the labels +/– or anode/cathode markings.
Power On Test: Plug in or turn on your 5V supply. All buttons should light up! If some don’t, troubleshoot by checking that each connector is firmly attached, and that that LED isn’t reversed (try flipping its wires if removable).
Tie Down Wires: Once confirmed, use zip ties or cable lacing to secure the daisy chain along your panel so it’s not dangling into moving parts (like joystick or buttons). A tidy wiring not only looks pro, it prevents accidental yanks.

For 12V setups, the process is the same but with a 12V supply. The chain concept doesn’t change. Just ensure any necessary resistors are in place. Often, 12V LED buttons have a small PCB or twist-in bulb holder that has the resistor – you wire those directly in the chain.

If you want to get fancy, you could wire a switch or transistor to control the LEDs (for example, only light up when a button is pressed or flash them). That goes beyond basic wiring – requiring an LED controller board or connecting to output pins on something like an IPac or Pac-Drive board. This guide assumes you want them either always on or all on together.

Troubleshooting Tips

One or more LEDs won’t light: First, verify power is reaching them. Use a multimeter or LED tester at the far end of the chain. If none in the chain light, check the first connection to the supply (it might have come loose). If only one is out, that LED or its wiring might be faulty. Ensure the connectors haven’t slipped off that LED’s terminals. Also double-check that LED’s polarity – maybe it’s wired backwards; flipping the connectors on that one could fix it. LEDs are diodes, so current only flows one way.
LEDs are very dim: This could indicate not enough voltage or too large a resistor. If you mistakenly used a 12V resistor value on a 5V supply, the current will be too low. Or if your supply can’t source enough current (unlikely with a few LEDs, but if you had dozens on a weak USB port, it might struggle). Check if the supply voltage at the LEDs drops significantly when they’re on (voltage drop due to insufficient supply). A common culprit: powering many LEDs from the Raspberry Pi’s 5V without a powered USB hub – the Pi’s 5V rail can dip. Solution: use a dedicated 5V power supply or a powered encoder board for LED heavy builds.
All LEDs flicker or turn off intermittently: This usually means the power source is not stable or something is shorting. If running from USB and drawing near the port’s limit, the port might be turning off power (especially if you see them flicker when all turn on). In that case, reduce brightness (add resistor) or move to an external 5V supply. Another possibility is a loose connection at the supply – a wiggling wire can cause flicker. Ensure screw terminals are tight or solder joints are solid.
Burnt-out LED (smells or visibly fried): Immediately cut power. This means the LED took too much current. Maybe a resistor was omitted or the wrong voltage was applied. Replace the LED (once burnt, it’s done) and identify the cause – add proper resistor or correct the wiring. If one LED in a parallel chain burnt but others are fine, it could’ve been a defective unit or a momentary short on that LED’s leads.
One section of daisy-chain out: If, say, LEDs 1-3 work but 4-6 don’t, inspect the chain between 3 and 4. The connector after 3 might have a broken wire or not actually be crimped onto the wire (manufacturing defect in the harness). Repair or re-crimp as needed. This is the downside of chaining: a break mid-chain cuts off everything downstream.
LED polarity confusion in harness: As mentioned, some kits wire black to +5 and red to ground (contrary to usual color norms). If using such a harness, follow the kit’s note: on the GeekPub kit, they explicitly say black is +5V and red is GND. So trust labels over colors. If unsure, test a single LED first with the harness to ensure it lights, confirming which is which, before connecting all.

By following this guide, you should have a smoothly glowing array of arcade buttons, whether you’ve chosen the simplicity of 5V or the higher voltage of 12V. The key takeaways are: match your LEDs to the correct supply or use resistors when needed, and use daisy-chaining to keep wiring manageable. With that, your arcade machine will not only play great but also look amazing in the dark!

To go deeper, check our arcade buttons buyer’s guide.

Sources:

Reddit r/cade – “How to wire LED arcade buttons”: user journeymanSF’s wiring explanation for 12V LEDs, daisy-chaining plus power source tips, and user Velvis question and answer about needing resistors on 5V/12V reddit.com
The Geek Pub – Arcade Controls Wiring Instructions (details on button LED pin polarity and daisy-chain wiring with zero-delay encoder) thegeekpub.com
DrZzs Electronics Blog – “Why choose 12V vs 5V LEDs” (explains that LED forward voltage is same and resistors drop difference, brightness parity) drzzs.com
Reddit – Does using a 12V LED on 5V make it less bright? (community answer: it draws less current and is dimmer, confirming half-brightness scenario) reddit.com
Forum ArcadeControls – LED button wiring discussion (advice on using proper resistor, mentions that “12V LED already has a resistor, replace if using different voltage”) forum.arduino.cc