What is it?

Behind the Arduino Opta's AUX tab there are pads for interfacing with I2C and serial. These are not easily accessible, so this kit includes board + edge connector to break them out.

Why did you make it?

I was considering using a MIDI interface with the Arduino Opta. I still may as since I can now access UART, MIDI is also possible and has worked well as an input in preliminary testing.

What makes it special?

It's a simple breakout, but it's a unique device. It's good for experimentation, but certainly not appropriate for any sort of critical or harsh environment that you'd traditionally use a PLC for. Use at your own risk.

Of course, if you've seen some of the cabinets out there, a lot more kludgy stuff goes on than should be the case. Use responsibly. Also, it would seem the chip is a 3V3 device, so I highly suggest using that voltage level for interfacing, not 5V.

Other Details:

• Labels are accurate with respect to the AUX out, but will be incorrect if used on the input side of an expansion module.
• New version includes offset pins for SSD1306 OLED screen or other devices, which you can optionally include. - I2C output tested with base module as well as SSR expansion.
• Example code for use with SSR expansion and SSD1306 OLED available here
• Example taking MIDI signals and displaying the pitch value via an SSD1306 with an SSR expansion and AUX adapter
• No issues so far using serial with MIDI input testing.
• Still experimenting, so feel free to ping me with questions or neat stuff that you've come up with!
• Options for 1-pac or 2-pac include 1 or 2 of entire kit respectively, and one OLED screen will be included for each kit purchased IF that option is selected. I.e. select 2-pac and OLED option, receive 2 boards, 2 adapters, 2 OLED screens. Select 1-pac and OLED option, receive 1 board, 1, adapter, 1 OLED screen.

• OLED screens are slightly different than pictured per a new design.

• Please let me know if you have any questions or comments - hi@jeremyscook.com - PCB design files linked may not be the most current version.