I think that's likely a "self-contained" module, just connect 5V.
What's the current draw of that device?
I'd rather see you switch it on/off through a transistor.
why do we need a driver for laser diode? what is wrong to connect it like an LED since it seems it works.
What is wrong is that the forward voltage drop of a laser diode is not as stable as an LED. So to run the laser at anything close to full power you need a much better current regulator than a simple resistor.
Sometimes this involves optical feedback where the current is adjusted according to the brightness of the LED.
Also an over voltage to a laser will kill it very quickly where as LEDs are very much more tolerant of this.
The "it seems it works" sort of evaluation is not good enough to provide a reliable, long lived piece of electronic equipment.
Yes, but 5V is usually a module that contains a regulator. Otherwise he would either have already fried it or it would not lase at all (due to undervoltage).
Something else to keep in mind is that laser diodes are typically 3-pin devices (one pin is an output from a photosensor for feedback to the regulator for current control).
you can't just connect a laser diode directly to an arduino.
if the laser module you have has 2 wires coming out, that is likely to be closer to 3 volts, than 5 volts (many small, low powered laser modules are 3.3VDC).
If you aren't looking for speed in on/off (under a few Hz) then you should be fine. There is a small and inconsistent delay in that style of laser driver - which is basically just a current and voltage regulator. That may also put too much draw on your Arduino, current-wise.
If you are looking to gain high-speed control, then you will need to look into a modulated laser driver. Those drivers keep the laser diode powered, but just below the lasing threshold, which keeps it "warmed-up" and gives it a nice fast response. modulated laser drivers also can't be powered from an Arduino, too much current.
that's a great starting point as far as lasers are concerned. not dangerously strong, IR filtered, totally self-cooling, and the modulation is probably in the 5KHz range.
Of course, use caution with ANY laser. And I would also STRONGLY recommend goggles with anything that was advertised over 5 mW (yes, FIVE MILLIWATTS) -- Especially the cheapo pointers. While their visible component may not seem blindingly bright, the cheaper lasers do not have IR filters (and neither do our eyes, btw) and often the crystals aren't properly aligned, which causes them "leak" IR. LOTS of IR. So while your laser is listed at "<5mW" that is not measured individually, that is what it is designed to measure at. It takes a lot more than 5mW of IR laser power for a crystal to convert that IR into 5mW of visible green light.
