I want to control the following laser module from an arduino digital output:

  • Specification V2 – Aug 2010
  • Wavelength : 650nm +/-5nm
  • Output Power : 4-5mW
  • Operating Voltage: V2 = 3.0-4.0V
  • Operating Current: 15-20mA
  • Operating Temperature: 10 – 40°C

What's the best approach - I've looked at diodes for voltage drops, resistors and regulators but I really don't know which to use. The variability of the voltage and current in the specs is rather confusing.



The best way is to use a dedicated laser driver IC such as the iC-WKL from Global Laser.
This will take care of the careful regulation needed. It expects a laser diode with an inbuilt monitor diode for optical regulation.

Other less ideal ways to drive them are:

  • A series resistor to limit current as you would with a normal LED - some more robust modern diodes can apparently be used like this quite successfully.

  • A constant current setup.

Laser diodes are usually very sensitive to variations in current/voltage (the lasing threshold is quite close to the maximum threshold so not a lot of room for error) so check your datasheet to see how much "play" you have.

This page has some good info on laser diodes.

| improve this answer | |
  • \$\begingroup\$ It's a module with a current regulator built in, not just a diode. Given this, would a series resistor be ok? According to my maths the resistor will be between 50-133R, seems like quite a large range to me. \$\endgroup\$ – JimmyP Jan 15 '12 at 14:29
  • 1
    \$\begingroup\$ @JimmyP - Can you link to the datasheet? \$\endgroup\$ – Oli Glaser Jan 15 '12 at 16:37
  • \$\begingroup\$ Couldn't find a data sheet, only what was provided above. I've treated it like an LED and added a series resistor, hooked the meter into it and everything's working as expected. Cheers. \$\endgroup\$ – JimmyP Jan 23 '12 at 9:59

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.