+1 for using the 5V already available to power the Uno, through the 5V pin, if it has the current capability to run the relay coil and the Uno. So in this case a buck converter will add some isolation between the 12V power supply and the Uno. If you are powering just a couple of sensors or small LEDs from the 5V, you are fine with Vin or the jack, just be aware the for heavier currents the on board regulator may not hold up. Then the rated current of the DC DC converter is available on the 5V line. I would use a buck converter to drop the 12V to 5V and connect that to the 5V on the Arduino, bypassing the, weak, 5V regulator. The higher the voltage the less current can by supplied. The amount of current depends on the voltage input to Vin or the power jack. Attach blue wire to the top dark outlet screw and red to the bottom screw. Cut 4 blue and 4 red wires 10 in length and crimp a fork terminal on one end. Power Arduino and relay module from UPS battery and 5v adapter. Attach a current sensor or your inefficient adapter to 5v to the arduino to detect power on/off in mains. The on board 5V regulator is not heat sinked so will supply limited current before it overheats and shuts down. Break off the tab connecting the darker terminal screws on all of the outlets. Build a relay circuit with your UPS on the NO terminal and power to COM. Powering through Vin or the power jack means that the Arduino and all peripherals that are on the 5V rail are powered by the onboard 5V regulator. the problem is when the relay is triggered to close the circuit of the electric lock my arduino resets sometimes (not all the time), so I started disconnecting one thing at a time (servo, other arduinos etc) to identify the problem, I'm powering the arduino and the electric lock from a 12v 5 amp power supply, and the relay from a separate 5v 10A power supply (to benefit from opto isolators of the relay), I tried everything but nothing seems to fix the problem, the arduino doesn't reset every time, but about twice or once every 10 times, I connected grounds of arduino directly to ground of 12v, then to ground of 5 volts, I checked the voltage of 12v supply when the relay is activating and it didn't drop, I powered the electric lock from a second 12v5a power supply just to isolate it, but the problem still occurred from time to time, this forum is kinda my last hope hhh, feel free to ask questions and offer suggestions and why not straight solutions (with explanation hopefully), thank youīe careful when using the power plug or Vin. I would prefer the SSR since there is less failure possibility (no moving parts).Hello everyone, I've been diagnosing this problem for 4 days now without finding a solution (not really understanding the problem), I'm building a boxing arcade, I already made a basketball arcade with a lot of shared components and it works. I will do the same with another of these relay with the DC polarity inverted to close the window.Īlso, to drive the relay I may use a relay board ( this one) or a SSR board ( this one).

Since the relay has 3 separate contact and I need to drive a motor inverting polarity (window opener), I was thinking of using 1 for opening the window connecting + and - of the motor to 2 contacts and using the third to connect 220V AC that power the 12V DC power supplier, so there shouldn't be arc problems. The relay is a Relpol TYPE R15 3PDT mounted on this screw terminal, so no problem for board traces. In this case, I suggest using the automotive Bosch relay, And making a driver circuit for it.

Normally if you are using one of the hobby relays that are available on eBay, The connection terminals will only take approximately 7A. In this case how heavy are the traces, Are they on both sides of the board, and what kind of current will your connection terminals take. You need to look at the board that you're using as well.

As I have said before, The current/Voltage rating of the relay is not the only thing you should consider.

Arduino relay ac power