Hi Guys
anyone got any code and advise on getting one of these laser working on a arduino UNO ?
there are 3 pins on the laser, with the unit facing the right the top pin is Signal, middle pin is VCC5v and bottom pin is Ground
I am a total newbie with this so any help would be great
Thanks
in advance
In the absence of any firm detail, 5v to to middle pin, ground to bottom pin and connection to Arduino to top pin. Don't forget to connect the grounds if using a separate power supply for the laser.
Hi dannable
how do I do what you mention and what code do I use ?
Thanks So far though
Use digitalwrite() to set the pin you have connected the laser to to HIGH or LOW. It may work in reverse, so when you set it LOW it's on and off when HIGH.
Be careful!
Those "Keyes" PCB's is meant for a lot of different sensors/LED's etc. and they just slap on what ever that comes to mind.
Obviously only two pins is used when powering the Laser-module - my best guess is VCC + GND.
// Per.
The code depends on what you want to do with it.
Have you done "blink" yet?
As Zapro said, the module probably only uses VCC and GND. Would be nice to have the datasheet on the laser diode.
Paulcet:
As Zapro said, the module probably only uses VCC and GND. Would be nice to have the datasheet on the laser diode.
You won't get any datasheet when buying something that cheap.
It's the most basic laser diode setup you can imagine - a bare diode bonded to a piece of pot metal and a simple resistor as current limiting. I bought a bag of 20 at a time to see how bad they were, and not that bad actually 
// Per.
Zapro:
I bought a bag of 20 at a time to see how bad they were, and not that bad actually
Not bad at all.
As usual, need to carefully re-solder the flying leads - I always de-solder them, pull the insulation back and twist the strands, solder that and let the insulation cover over the tinned part, thus reinforcing that point, and re-solder them. I do this both ends, it largely prevents repeated flexion and rapid breakage at the point of weakness where between where the insulation covers and where the solder has made the strands rigid.
Do not run them continuously (unless in the refrigerator).
Gotta love these "modules" that are nothing more than the main component on a tiny PCB with pins, with nothing more than one resistor and maybe a capacitor. In this particular case, difficult to see whether the second resistor and third terminal has any function whatsoever.
That one is marked '-' at one side and 'S' at the other, its a standard servo layout,
"-+S" (ie ground, 5V and signal)
MarkT:
That one is marked '-' at one side and 'S' at the other, its a standard servo layout,
"-+S" (ie ground, 5V and signal)
But the laser is a two terminal device.
And what's the 10k resistor for?
There is usually a photosensor on the laser diode meant to detect the power level. In a laser pointer, it is wired to a few transistors that regulate the current.
Who knows what this is?
polymorph:
There is usually a photosensor on the laser diode meant to detect the power level. In a laser pointer, it is wired to a few transistors that regulate the current.Who knows what this is?
The construction is so basic, that it does not even employ a sealed can-type laser. It's the bare die that's bonded to the board.
There is no feedback.
// Per.
Maybe you are meant to add your own negative feedback driver circuit, and the 10k resistor is part of the photodetector, and the reason there are 3 pins. Maybe.
The below link has some review comments on the workings of the laser module. I got the bottom 10 pack.
polymorph:
Maybe you are meant to add your own negative feedback driver circuit, and the 10k resistor is part of the photodetector, and the reason there are 3 pins. Maybe.
Oh, go on 
!
Yes, it has negative feedback. It is called a resistor! Despite Mike's usual protestations, it works just fine, albeit somewhat inefficiently as the diode voltage is close enough to 2.17V.
I have a quantity of the ones with wires, as described above. I see no reason to pay substantially more for them on a board; they work just fine, but not having one of those mounted specimens, I find it difficult to discern from all those photos however the series current limiting resistor is in fact just on the end of the little chip of PCB.
It does have the advantage that it will respond to on-off modulation to a quite high frequency.
