hi i would like to add mini laser diode to my board as per photo can this be done?
Is the laser module a 5 V version with a "910" or "91" or "91R" resistor?
If so, you can connect it directly to the Arduino as it will draw no more than 25 mA.
If it is the 3 V version with a "330" resistor, you must add a 47 Ohm resistor in series.
Do be careful not to touch the metal casing to any part of the circuit (such as ground) - it is the positive terminal of the laser.