/diy/ - Do It Yourself

>>1145781
>>1145796

So the thing I am doing is a switchbox for Arduino, where I could choose between usb and wall adapter and also have a multimeter in that same box too, so if I wanted to measure current there would be no need for extra leads.
The reason for battery would be to have the box also work also as independent battery powered multimeter if needed.

>>1145806
I drew the circuit diagram wrong. Relay should disconnect the battery when power plug is in and close the another contact.

Here is another rough sketch. Still going to need to figure out how to switch between the power going to ammeter.