I bought one of these but seeing they appear to be inverted to what I wanted, eg 0 to power the relay, which means they all power at boot up, I decided to modify it.
I removed diodes IN1,2,3 & 4 and resistors R1,4,5 & 8 (I note in the documents these can have different numbers).
I then connected 4 x 300ohms resistors to the right hand pads where the diodes were and connected the other ends to the right hand pads where R1,4,5 & 8 were.
I then linked all the left hand pads where the diodes were together and to GND.
Put the Vcc - JD-Vcc link in.
The module doesn't now need 3.3v from the RPi, connect the Vcc connection on the module to 5v on the RPi.
This requires some level of skill at soldering, and obviously at your own risk.
- relay mod.jpg (13.78 KiB) Viewed 5092 times
- relay_back.jpg (43.56 KiB) Viewed 5092 times
- relay_front.jpg (62.41 KiB) Viewed 5092 times