1
\$\begingroup\$

I am building a breadboard circuit to be controlled by Arduino. The circuit consists of about 20 bright leds simulating a vehicular lighting system (ten leds for headlight, 4 in taillight, 3 for each directional light, or something like that).

Since these leds would draw up to 500mA @ 6V, I would like to power the breadboard from a wall wart.

But, at the same time, I would like to run my Arduino from USB power, so that I can keep updating my logic until everything works fine.

It is important to note that I plan to drive the LEDs with transistors, their bases connected (via resistors) to Arduino output pins.

So my question is: how should I ground and connect both circuits so that 6V (or more if I change my mind) from the breadboard source does not "reflow" to the Arduino while it is being powered by USB?

It is possible, isn't it? Should I take any special care?

\$\endgroup\$
2
\$\begingroup\$

Simply connect the breadboard/wallwart ground to the Arduino ground. As long as you don't connect the wall-wart positive to the Arduino, there should be no problems.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.