I’m working on my own module. It is a relay module. It is different from the module already sold by Seeed Studio. My module communicate via the I2C two wire interface. It uses the PCF8574 I2C I/O expander to drive 8 120/240 Volts, 5A relays.
I have used “Saturn PCB Design Toolkit” to calculate route width. I really want to make my module Gadgeteer compliant. If someone notes something missing or wrong, do not hesitate to let me know.
I’m also interested to know if this module could be interesting for someone.
The module also uses an external power supply because it drives about 0.7A with all the relay activated. The IC responsible of the 5V supply is a MuRata OKI-78SR.