What is the real power of these lasers?
They always say 5mw on ebay but my local electronics shop has them packaged as <1mw.
Here in Aus we have a 1mw legal cap.
If i run these under powered at 3v would their output be under 1mw?
There are two ways sellers express the power of a laser.
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The power the laser takes, known as the input power.
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The power of the beam it produces, this is known as the output, or optical power.
OK.
Yea that kind of what im hoping, underpowered, they are 1mw...
Trouble is no one seems to have a data sheet for these
That's the problem with cheap bin reject stuff you get from China.
What do your regulations specify, optical or input power?
Perhaps there is some way to use physics to determine the actual watts of light emitted?
Something about frequency and intensity?
I have found this:
Hand-held devices, known as laser pointers, designed or adapted to emit a laser beam with an accessible emission level greater than 1mW are classified as weapons under Schedule 13 of the Customs (Prohibited Imports) Regulations 1956. These laser pointers are prohibited from import into Australia unless permission has been granted.
But then how does my local electronics shop (Jaycar) sell them?
You can't lower the power by reducing the voltage. Fall below the forward bias level, and it goes out. Use PWM to vary the duty cycle to modulate the power. 5mW input will be <1mW output since laser efficiency is under ~20%.
How do you get laser engravers/cutters? Mine is 5W OUTPUT.
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From the page you linked to:
• Output power: <1mW
Leo..
This is my point.
The same laser is packaged as <1mw...
What are they really?
I have laser modules with tiny CC circuit boards able to fit in a narrow tube from about 10 years ago. $4.50 got a bag of 10. I got a few of those.
I input 20mA at 5V. That's 100mW input. The dot is brighter than my laser pointer.
When power is given as an electrical spec (without "optical") then its INPUT current for the support electronics. Since laser efficiency varies, but is consistently under 20%, ouput power has to be individually measured, and low cost vendors are NOT doing that.
Hey importation of a peanut butter sandwich is prohibited in Australia and look how dangerous they are.
Probably because the customs deceleration is misleading or wrong or none existent, or the customs man ( or woman ) did not check them or apply the rules.
You won't know unless you measure it, and I don't think you have the equipment to do this.
Albert used a cadmium sulfide photocell.
How did he calibrate it?
Thanks for the responses.
So, what is an alternative LOW COST to these?
I just want a red dot gun sight for a toy gun
He invented the quantum. Frequency makes voltage, number/intensity makes current.
Next summer it will be 50 years since I took physics. When Albert did it, he got a Nobel.
Collimate a red led, you won't blind anyone by accident. Even lasers have focus optics.
Ah, that Albert. 
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You can make your own laser power meter using an IR detector such as the MLX90614 (or equ.)
Use a high-temp high carbon spray paint (auto engine exhaust black) and paint one side of a borosilicate glass microscope slide cover slip. Use adheasive to glue 1 corner of the slide to a push-pin.
This is your laser target. Mount vertically or horizontally in free air.
I'll post temp chart as soon as I retrieve them from backup. A 1mW laser pointer will have an under 1-deg F temperature rise.
The chart below was calibrated using a semi-professional ($300) laser power meter:
RAW:
Better call it a "blaster", lest it get banned in Australia, too. I thought Canada was rules-happy.
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