Using Onion expansions with other micro controllers
I wonder whether the expansions for the omega can be used with other micro controllers as well. In particular I want to use the onion relay expansion with an arduino.
I've heard that the omega communicates with its expansions via I2C. Furthermore Arduino is capable of i2c. I just need to know what pins are used for the i2c communication (20 & 21? As for regular i2c connections?) and what data bytes the relay expansions expects.
Thanks in advance for any help :)
@Peter-Harrald Yes, Omega I2C based expansions can be used with (e.g.) Arduino. Omega I2C is on Omega GPIO pin 20 (SCL) - Analog Pin A5 on Arduino UNO and Omega GPIO pin 21 (SDA) - Analog Pin A4 on Arduino UNO, also will need to ensure you have GND connected in common.
Only thing you may need to be careful with is that the Omega uses 3.3v and (most) Arduinos use 5v - though both can actually handle signals in the 3.3v to 5v range.
I have successfully done this using the Omega to drive an I2C 16x2 LCD display intended for use with Arduino; and using an Arduino to drive an Omega OLED expansion
To figure out the data bytes etc that the Omega relay expansion expects, I would suggest looking at the relay expansion code that can be found amongst the code at https://github.com/OnionIoT/i2c-exp-driver
Hope that helps :-)
Thank a lot!