Switching Relay Output using Audio Signal

Audio Controlled Relay ST-ACR1


  • Switching Controlled by Audio Signal
  • Switching from Mic or Line Signals
  • Silence Sensing
  • DPST switching relay output
  • Open-collector slave output

Connection Setup

Audio input, Light output
Alarm signal trigger system

Device Wiring Connection

Audio wiring input connection

The module uses 24Vdc for powering up the audio sensing input and relay output.

Power supply connection

Manual input to control the output relay.

Adding manual control

You can purchase the module ST-LCR1 to extend out for more relay outputs.

Adding more relay output for interfacing to external system.


  • Audio input: 10Kohm balanced bridging
  • Input connections: may be connected balanced or unbalanced
  • Control output: open-collectpr @ 25mA
  • Retrigger delay: 250ms
  • Relay output DPDT (up to 230Vac, 2A)
  • Activation response time: 25ms
  • Dimension: 17 x 76 x 39mm


Product dimension size

Size Dimension

Audio Controlled Relays (other models)

ST-ACR1 Audio Controlled Relay

Relay is actuated by audio line level source.

ST-ACR1M Audio Controlled Relay

Relay is actuated by microphone input source.

ST-ACR2 Audio Controlled Relay

Can be used as a silence sensor detection device. Relay release delay is extended by 5-50sec.

ST-LCR1 Logic Controlled Relay

Logic controlled relay. Relay output is DPDT (dual pole dual throw)

ST-LCR2 Logic Controlled Relay

Pulsed controlled relay. Relay output is DPDT (dual pole dual throw)

ST-VOX1 Voice Activated Relay

Voice controlled relay output. Input voice can be from microphone or audio line level. Can be used in a voice intercom setup.


Audio Activated Relay PIC-125

Click here to but Audio Activated Relay [PIC-125] product.