I have 12v poser supply for electronic lock. It has 3 valuable pins: +12V, GND and PUSH. So, when I want to unlock the lock, i need to push PUSH pin to GND. How can I push 12v line to ground with Arduino Nano?

  • \$\begingroup\$ You can likely just use a MOSFET. For a definite answer, you should provide a link to a datasheet or product page for the electronic lock. \$\endgroup\$ – user133493 Mar 21 '17 at 7:11

A definite answer isn't possible without more information about the lock. You likely want something like this:


simulate this circuit – Schematic created using CircuitLab

Drive IOPIN HIGH to ground the PUSH pin.

Many other parts could be used in place of the IRLML2502. It's convenient for driving directly from an IO pin. Whether you need the flyback diode D1 depends on the lock.

  • \$\begingroup\$ Yes, exactly what i need! \$\endgroup\$ – Neka Mar 21 '17 at 7:33
  • \$\begingroup\$ Why I cant connect IOPIN to PUSH directly and send logical 0 (push to GND), or 1 (push to +12V)? \$\endgroup\$ – Neka Mar 21 '17 at 7:36
  • \$\begingroup\$ If you did that, the IO pin of your Arduino Nano would sink whatever current flowed out of the PUSH pin of your lock. They can probably only sink about 30mA (check the datasheet), but the lock may source much more than that. Without more information about the lock, it's impossible to say. It probably does, and the result would be permanent damage to your Arduino. \$\endgroup\$ – user133493 Mar 21 '17 at 8:22

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.