LED strip feedback

Add a WS2812 LED strip to your machine and see its state at a glance — no screen, no app, just a strip of LEDs that tells you what's happening.

What it shows

The position tracking feature is particularly satisfying: map LEDs to your machine's physical axes, and as the tool moves, nearby LEDs brighten. You can see where the machine is cutting without looking at a screen.

How it works

Every LED on a WS2812 strip has a small driver chip. The controller sends one stream of colour data into the first LED. That LED keeps the first colour for itself and passes the rest on to the next one, and so on down the strip. This means:

• Data only flows one way. The strip has small arrows printed on it; connect the FluidBoard to the end where the arrows start (DIN), not to DOUT.
• The signal is timing-critical. Noise or a poor ground shows up as flickering or random colours, usually starting at the first LED.
• A strip can be cut at the marked cut lines, and pieces can be chained by connecting DOUT of one piece to DIN of the next.

Wiring

• Connect the data line (DIN) to 5V output 4 (Out4, gpio.3). The strip gets a 5V PWM data signal from this pin. It is shared with MOSFET output 3, so use one or the other
• Power the strip with the voltage it is rated for (5V or 12V): either from an external 5V/12V supply, or from the FluidBoard's own supply with a 470 µF capacitor across the strip's power input
• Keep the data wire short, or add a 330 Ω series resistor for longer runs
• Tie the grounds together: strip, power supply and FluidBoard must share a common GND

Some practical notes:

• Place the resistor at the strip. The series resistor works best at the end of the data wire closest to the first LED.
• Mind the capacitor polarity. The 470 µF capacitor is an electrolytic capacitor: the minus side (marked with a stripe) goes to GND, the plus side to the strip's supply. Place it at the strip's power input.
• Connect GND first. When connecting a strip to a powered system, connect GND before data and power. A data line connected without ground can damage the first LED.
• Budget the current. A 5V WS2812 LED can draw up to about 60 mA at full white. 40 LEDs at full white is up to 2.4A. The status effects rarely run every LED at full white, but size the supply for the worst case. For longer strips, use an external supply.
• Feed long strips from both ends. The thin copper of a strip drops voltage over its length. If LEDs at the far end look dim or turn yellowish or reddish, also connect power and GND at the far end. Only connect data at the start.

Mount the strip where you can see it from your usual working position, and protect it from coolant and chips, for example in an aluminium profile with a diffuser cover.

Configuration

led_strip:
  pin: gpio.3 # 5V output 4
  type: WS2812
  leds: 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  color_order: GRB
  direction: "XXXXXXXXXXX YYYY XXXXXXXXXXX"
  travel: -300 -100 300
  feedback:
    enabled: true
    idle_brightness: 70
    idle_breathe_period: 30000
    running_boost: 10
    position_boost: 25

The leds list maps physical LED positions to logical indices. The direction string assigns each LED to an axis (X, Y, or space for gaps). The travel values define the machine distance for each segment in mm.

In the example, the list runs from 40 down to 0, which reverses the strip. You need this when the strip is mounted with its data input at the opposite end from where you want the effects to start, so you don't have to rewire it. If the position tracking moves the wrong way, check the order of the leds list against how the strip is physically mounted.

Most WS2812 strips use GRB colour order, but not all of them. If red and green appear swapped, change color_order.

Testing it

1. Power up. You should see the rainbow animation on the whole strip, followed by the idle breathing effect.
2. Jog each axis from one end to the other, and check that the bright spot follows the tool along the right part of the strip and in the right direction.
3. Trigger a feed hold and check for the orange pulse; resume to clear it.
4. If you have a probe, touch it and check for the white flash.

Troubleshooting

Related guides

• High power mosfet outputs: gpio.3 is shared with mosfet Out3
• Lasers and 5v outputs
• Probing