Bridge Widget

✦ Special

The Bridge widget creates a device-to-device connection through the VWire server. When a source device writes a value to a pin, the Bridge automatically forwards it to a target device and pin — without any custom server-side code. Use it to sync two devices, cascade commands, or build simple automation chains.

Default size: 4 × 2 grid cells

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Configuration

Property	Type	Default	Description
Source Device	device	—	Device whose pin value is forwarded
Source Pin	V0–V255	—	Pin to read from on the source
Target Device	device	—	Device to forward the value to
Target Pin	V0–V255	—	Pin to write on the target
Transform	none | scale | invert | custom	none	Optional value transformation
Label	string	—	Widget label

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How it works

Source Device → Vwire.virtualSend(V0, value)
              → VWire Server sees V0 update
              → Bridge widget rule activates
              → VWire Server writes value to Target Device V5
              → Target Device VWIRE_RECEIVE(V5) fires

The bridge is evaluated server-side every time the source pin receives a new value.

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Use cases

Master light switch

Source: ControlPanel V0 (Switch widget: 0/1)
Target: LightDriver  V0 (controls relay)

A switch on the control-panel device directly turns the light driver relay on/off.

Temperature relay between sensors

Source: OutdoorSensor V0 (temperature in °C)
Target: DisplayHub    V3 (Value Display: outdoor temp)

Replicate a temperature reading from a sensor device onto a separate display device.

Inverted control

With Transform: invert, a 1 from source becomes 0 on target and vice versa.
Use to control an active-low relay or to invert a switch behavior.

Scale transform

With Transform: scale, map the source range to a different target range:

Source: 0–100 (slider percent)
Target: 0–255 (PWM duty cycle)
Scale: ×2.55

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Firmware: target device

The target device receives values via its normal VWIRE_RECEIVE handler — it doesn't need to know it's being bridged:

VWIRE_RECEIVE(V5) {
  int val = param.asInt();
  analogWrite(PWM_PIN, val);
}

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Notes

Single direction

A Bridge is unidirectional. To create a two-way sync, add a second Bridge widget with source and target swapped.

Loop prevention

Do not bridge A→B and B→A on the same pins — this creates an infinite loop. VWire detects simple loops and drops repeated values, but complex chains may still misbehave.