I would like to share my project ‘How to invert signal to a Relay’
I searched numerous websites but i couldn’t find solution, there were some ideas of using a NPN transistor for inverting signal on a single channel relay but no for multi. Many users were interested in tasmota where you can invert relay signal using iRelay option but in my case i was trying to use sinric pro(cloud based iot control with alexa skill integration) to control a relay, the problem i faced is when it sends off signal my relay is on and vice versa, this was due to active low relay, also there is no option in sinric pro to invert signal. After lot of searching i found an inverted IC ULN2003 which can invert signal for 7 channels max and give ouput as ground incase of high input, also vice versa.
Connections for ULN2003
Ouput signal from any development board to Input 1, if more Input 2,3 etc.,
Ground to Ground
COM of ULN2003 i left hanging
Output 1,2 etc., to relay IN1,2 etc.,
I think you can use any inverted IC for this purpose. Enjoy