Quad Relay Controller
Remotely controlled via wired switch inputs
Optional USB, RS-232, or wireless RF


  • Description
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  • Features
  • Licensing
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  • Quad Relay Controller
    Featuring wired remote control inputs. Includes AC adapter.

    (Also available with USB, RS-232, and RF options.)

    The Quad Relay Controller is a remotely operated device that can be used for activating up to four separate electrical circuits. The controller has four onboard relays, each with 10A contacts (limited to 5A by board traces). These are Form C relays having normally-open, normally-closed & common contacts. The following control methods are possible:
    • External switch closure (four inputs)
    • Serial host command (model QRLY-5150 only)
    Each relay is individually controllable by one of four external switch closure inputs. To implement a switch closure input, simply apply a length of 2-conductor wire such as telephone cabling or speaker wire and connect a normally-open switch of your choice. (Suitable switches include reed, pushbutton, rotary, toggle, etc.)

    We offer three (3) different device models:
    • QRLY-4151: Basic switching
    • QRDS-1000: Delayed switching
    • QRLY-5150: Host control (USB, RS-232, or wireless RF)
    Choose a standalone model (QRLY-4151 / QRDS-1000) for wired control or a host-control model for accepting serial host commands. (Host control options include USB, RS-232, and RF wireless.)  The following purchase options are available:
    • Basic Switching
    • Delayed Switching (0 to 3 minutes)
    • USB host control
    • RS-232 host control
    • Wireless RF keyfob remote
    The product can be used in a variety of applications:
    • Robotics
    • Industrial control
    • Animatronics
    • Security
    • Medical devices
    • and more!


    To support a variety of applications, we offer the following devices and options listed below:

    • Basic Switching (standalone, for general purpose applications)
    • Delayed Switching (standalone, featuring selectable delay: 0 to 3 minutes)
    • USB  (includes 6-foot host cable with type 'A' connector)
    • RS-232  (requires 9-pin serial host cable, not included)
    • Wireless RF  (includes keyfob transmitter with battery)

    Basic Switching


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    Delayed Switching


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    USB host option

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      RS-232 host option

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      Wireless RF option
    (with keyfob transmitter)

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    Serial Host Commands:
    (QRLY-5150 devices - except RF option)

    When using a serial communications method (TTL USART, USB option, or RS-232 option), the host may issue commands for relay control.  You may use a terminal emulator program such as HypterTerminal or Docklight to issue commands.  Alternatively, a custom developed application may also be used.  Available commands are listed below:
    • RONn [ttt] --Activate relay   [n = 1,2,3,4] [ttt=duration (secs)]
    • RON! [ttt] --Activate all relays
    • ROFn       --Deactivate relay [n = 1,2,3,4]
    • ROF!       --Deactivate all relays
    • GETn       --Get relay state  [response = "OFF" or "ON"]
    Each command to the controller must be terminated with a carriage return (13) character.  (Responses from the controller will also be appropriately terminated.)  "OK\r" is returned by the controller in response to a valid relay activation or deactivation command.  The following examples illustrate proper command usage:
    • RON2\r     -- Activate relay #2
    • ROF2\r     -- Deactivate relay #2
    • RON2 025\r -- Activate relay #2 for 25 seconds, then deactivate
    • GET2\r     -- Get activation state for relay #2


    Four (4) relays, 10A contacts (5A actual, limited by trace width)
    Four (4) wired switch closure / TTL inputs
    Optional variations include basic switching, delayed switching, USB, RS-232, and RF
    Includes AC adapter
    Optional plastic enclosure with mounting flange

    Design Licensing

    This item is available for licensing to OEMs. This design is available for OEM licensing.  Licensing permits your company to manufacture this item and allows you royalty-free sales and distribution rights.  Click here for additional details.



    • We keep a limited supply of this item on hand. A lead wait of 2 to 3 weeks may be incurred.
    • Shipments will not contain a CD or other software media. If software is applicable, it will be delivered electronically. (A valid email address is required for delivery.)

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