I’m using a 12v relay module from SainSmart ( https://www.sainsmart.com/collections/relays/products/16-channel-12v-relay-module ) with a pin expander MCP23007 and my Particle Photon.
The MCP23007 is powered thanks to the VIN from the Photon.
So you have : RELAY <—> MCP23007 <—> Particle Photon
I have discovered that I don’t need to power my Photon with the USB when the relay is powered by a 12v arrival. And everything is surprisingly working well…
Why ? Is it ok for the Photon on the long term ?
By the way, do you know any other relay module with 16 channels ?
@julienfoodgie, the relay board has its own 5v regulator which you are connecting to Vin of the Photon. This is why USB power is not required.
thanks for your quick answer.
What do you think about this relay board ? Are there any better (bigger) boards ?
@julienfoodgie, it looks good. However, ControlEverything has 24 and 32 relay boards that are I2C controlled if you are looking for more relays.
@peekay123 thanks for your help. I followed your advice and it works very well.
I bought an other 8 relays board and want to connect it to my master board but I don't understand the address jumpers. Do you have any idea ? I've opened a topic on the matter:
This new discussion should be continued in only one thread (the new one).