Bi-directional wireless I/O remote control application boards

November 09, 2012 // By Julien Happich
The BL118 bi-directional control device released by Radiometrix uses a half duplex radio transceiver to establish a two-way wireless link for remote control applications with a minimum of effort and no software input.

The radio link operates continuously, providing a valid communication link indication. The BL118 boards are used in pairs, a master/initiator and a slave/responder. The relays are activated when the state of the input on one board changes and vice versa. Compatible with any Radiometrix BiM-pinout wireless module, the best power versus range performance with the BL118 is achieved using the VHF BiM1 module. With a 10mW BiM1-173.225-10 module fitted, the average current consumption is only 1mA (relay off), achieving an open-field range which exceeds 500m. This allows for a 2-year operating life from D cells with a continuous data link.

The basic BL118 has a single logic input (diode protected, with pull-up) and an 8A 240V mains rated SPCO relay for NO/NC output. A 4% duty cycle communication interchange occurs every 2 seconds. Each unit consists of a 76x62mm board, mounted radio module, output, input, and support circuits, LED indicators and the BL118 chip itself. System address is set on an 8 way DIP switch and an SMA/MCX connector is provided for the antenna. I/O and power connections use 3.81mm pitch two part terminal blocks. 5V and 12V versions are available, differing in the relay type fitted, and the basic board is easily further customised for specific applications.

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