I was planning to make a laser alarm with KY-008 Laser Module and arduino, I heared some theory from youtube and forums that laser will over heat if continue use, I just want to have some advice in here as I know theres a lots of electronic proffessional in here.
travis_farmer:
laser diodes generally have a feedback circuit to prevent burn-out if designed properly. if your heats up a lot, it probably was not designed properly.
The laser module shown is the cheapest, bottom-of-the-barrel module. It's a bare laser diode bonded onto a FR2-substrate and slotted into the brass lens holder. It doesn't get any cheaper. No feedback, no regulation, just a single 0805-sized series resistor behind the diode.
// Per.
The laser module will reach thermal equilibrium after a few minutes of runtime. When the incoming amount of power balances with the level of radiated heat, temperature will not rise anymore.
It's a super cheap module. Don't expect long life from it, keep a spare one for replacement when it dies.
// Per.
kennethgomad02:
I was planning to make a laser alarm with KY-008 Laser Module and arduino
Do you mean a beam-break sensor.
Invisible IR LEDs (not lasers) and 3-pin IR receivers are usually used for that.
Leo..
I've no idea what kind of lifetime to expect, but if overheating were an issue, the module can be run with additional series resistance to decrease the current hence the power in the LED. The laser module is simply a diode in series with a 91 Ohm resistor to limit at about 25 mA.
The 91 Ohm resistor is apparent in the photo above on the outfacing side of the laser behind the brass ferrule. There's also a 10k Ohm resistor mounted on the PCB that goes between the middle pin and the "S" pin.
You will, of course, get reduced light output with additional series resistance.
MrMark:
The 91 Ohm resistor is apparent in the photo above on the outfacing side of the laser behind the brass ferrule. There's also a 10k Ohm resistor mounted on the PCB that goes between the middle pin and the "S" pin.
Just my .2 cents:
The 10K resistor is put there to confuse n00bs.
The small board they mounted it to, exsists with a multitude of sensors, transducers etc. Some of them require the pull-down resistor on the S-pin - In the case of the laser, the S-pin is not, and should not be used.
// Per.