The Arduino & I2C Relay Control Board is essentially an over sized Arduino shield that includes power regulation and relay driver circuitry, and brings all required off board connectivity to the backplane. Backplane connector J5 is designed specifically for the Arduino & I2C Relay Control Board.
As shown below, most power regulation and relay driver circuitry is mounted on the front side of the Arduino & I2C Relay Control Board.
The board also includes an Adafruit TCA9548A I2C Multiplexer breakout board to provide two I2C buses on the backplane. This enables communications with two I2C devices that have the same address, for example, Si5351 Clock Generator breakout boards.
The Arduino Mega plugs into the rear side of the Arduino & I2C Relay Control Board as shown below.
A link to the complete schematic for the Arduino & I2C Relay Control Board is provided below. The schematic should be self-explanatory.
Arduino & I2C Relay Control Board Schematic.
The Arduino & I2C Relay Control Board with Arduino Mega is installed in J5 on the backplane and fits nicely behind the LCDs as shown in the photos below. Note, this view was taken prior to adding the TCA9548A I2C Multiplexer breakout board.
A StarTech.com 3 ft Panel Mount USB Cable B to B – F/M – Panel Mount USB Extension USB-B Female to USB-B Male Adapter Cable – USB-B (F) Port (USBPNLBFBM3) provides the rear panel mount USB-B Female connector and extends this to a USB-B Male connector that plugs into the Arduino Mega. This is a very flexible cable and the excess cable is easily managed underneath the backplane board.
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