I have a 12 volt relay that I feed from a 12 battery and an analog arduino pin to In1 I also have a ground (all grounds are comon) When I attach the arduino Pin to the In1 of the relay it activates and stays on. If I remove the arduino and measure the arduino pin it measures mv. If I measure the In1 of the relay it measures little over 11v What's going on
Some relay modules have jumpers to remove the supply voltage from the pins used to supply and trigger the relay.
Some relay modules also work in a reverse principle so a HIGH instead of a LOW would trigger the relay or vice versa.
Some even have the pins mis-labled (Had at least two of those here)
I presume you are talking about a Chinese made relay module ? Hard to tell from here without a specific link etc.
Yup Chinese If there is 12v on the relay In pin will that not damage the arduino pin
12 Volts can and almost certainly will damage the Arduino if it is present on the I/O pins.
The forum doesnt like google drive for showing pics. That looks more of an oddball relay module than the ones I am used to seeing.
No jumpers and no OPTO in your pic. Those features would be a "preferred" choice to actually HAVE
I think you need to trace the tracks with a multimeter to make sure the pins are not labelled wrong.
Also maybe a better pic of the area between the pins and the relay itself.
Still having trouble I have found with 5v on the Vcc and a ground on the gnd pin If I ground the input pins the relay will work. So to activate the relay I have to ground the In1 pin on the relay board Having the arduino pin go low will not turn on the relay How to I accomplish this