One change I would make is to be sure pin 8 of the ULN2003 is connected directly to the power supply ground. You might not want to draw all the ground current through the traces on the Arduino board as show in the diagram.
One change I would make is to be sure pin 8 of the ULN2003 is connected directly to the power supply ground. You might not want to draw all the ground current through the traces on the Arduino board as show in the diagram.