BV107 BV4111 Relay


This is a project to operate the BV4111 serial relay controller with the BV107 wi-fi controller. This means that it is a simple task to switch anything a relay can switch but over a distance. There are two Windows programs that assist with this.


  • BV107 with firmware Vg_c1 (or later)
  • BV4111 with 8 way (or any way) relay.
  • 5V power supply


The arrangement is shown as above. A separate 5V power supply is needed with enough current to operate all of the relays. The 5 pin serial end of the BV107 exactly matches the serial input of the BV4111 and so a socket and plug arrangement can be used.

Set Up

Use the browser for the initial set up, join an existing wifi network, for this example we will assume the following:

  • SSID of router BT_ALLONE *
  • Password xa00JHFT *
  • Port 23
  • IP address of router *
  • IP address of BV107
  • Mode = 1

* change to suit your system

Use the Browser as described to set these values or alternatively if you already own a USB to serial device it is more reliable to use that with the commands. It is possible to use telnet at this stage but in the Widows version it is not possible to see what is being typed.

Step 1: Make sure the device is available by pinging the IP address in a command window:

Step 2: Alter the text in 'wifiinfo.txt' to suit your IP address and run the 'wifiRelay.exe' program.

Here I have turned on relay A. This of course can be done on any machine connected to the network. Any serial command accepted by the BV4111 can be typed here.

Step 3: An alternative command line program, use 'wifiRelayCmd.exe'

Here type 'q' to quit the 'wifiRelay.exe' program and type in the command line that switches off the relay.

You can also experiment with BVSerial which can open a socket instead of a COM port.