Laserbee or ?

[steviobee]

So.... I recently attended the excellent safety course held by James@LVR and obviously have come away very aware of the risks. So with this in mind and before I let any beams loose into the crowds I am looking to buy a power meter.

The question is which one? I am on a budget, as most, but want to make sure everybody's eyes remain intact!

I am looking at the Laserbee products, they may even be on here? So please pipe up.... Any other views please... Anything else that could be used for a 3w RGB projector (I'm not too fussed about testing the full power, I can borrow one for that, but one to test if I am within safe limits for on the road)

Thanks in advance

[swamidog]

think about using an OPHIR Laser Measurement 20C-A-1-Y-Sensor and a volt meter. it may well be cheaper than a laserbee, but still very accurate.

you can often find them on ebay in the 200-250$ (USD) range.

So.... I recently attended the excellent safety course held by James@LVR and obviously have come away very aware of the risks. So with this in mind and before I let any beams loose into the crowds I am looking to buy a power meter.

The question is which one? I am on a budget, as most, but want to make sure everybody's eyes remain intact!

I am looking at the Laserbee products, they may even be on here? So please pipe up.... Any other views please... Anything else that could be used for a 3w RGB projector (I'm not too fussed about testing the full power, I can borrow one for that, but one to test if I am within safe limits for on the road)

Thanks in advance

[WookieBoy]

Talk to James directly and he can point you in the right direction of where to get stuff in the UK...

[steviobee]

think about using an OPHIR Laser Measurement 20C-A-1-Y-Sensor and a volt meter. it may well be cheaper than a laserbee, but still very accurate.

you can often find them on ebay in the 200-250$ (USD) range.

Thanks - None there at the mo, but will keep an eye out, not sure I know how to use one though, but an electrical background should set me in good stead Seems a few similar items but need to Google for what the hell the numbers mean?

Talk to James directly and he can point you in the right direction of where to get stuff in the UK...

Good call, have PM'd him.

[swamidog]

they're super easy to use. you give it +/- 9v and the volt meter shows mW as mA. it's a 1:1 correlation.

i did a quick look. i don't see any at the moment, but they're often available from an israeli dealer.

Thanks - None there at the mo, but will keep an eye out, not sure I know how to use one though, but an electrical background should set me in good stead Seems a few similar items but need to Google for what the hell the numbers mean?



Good call, have PM'd him.

[steviobee]

they're super easy to use. you give it +/- 9v and the volt meter shows mW as mA. it's a 1:1 correlation.

i did a quick look. i don't see any at the moment, but they're often available from an israeli dealer.

Okay, sounds good, I will keep 'em peeled, if you do see one, i'd appreciate the nod :-)

[edison]

i would go for a laserbee but the power seems to go up in laserland so maybe an ophir head is better. Hopefully there will be a laserbee available that can go up to a higher power and keep the price level reasonable as it is now.

[norty303]

I've got a 3.2W Laserbee deluxe and its been fine for me so far.
If it gets to the point where I can't measure a single module on it, I'll be in a different sort of business arena anyway, and so a new power meter will simply be one of those 'things' you gotta have.

[JStewart]

The type of meter, (or more importantly), detector really depends on the type of measurement you are trying to undertake. Having a detector that can measure several watts of optical power, which is ideal for testing laser output power levels is best achieved with a thermal detector, as these can withstand the power levels that popular laser projectors output.

The advantage of thermal detectors is that they are not wavelength dependent, so you can just put the detector in front of any colour laser, or a combination of colours and the reading you see on the meter is the optical power hitting the detector.

Now, their downside is that they are a little slow to react to changes in output power, even the high sensitivity ones that only measure over a lower power limited range (<1W), may take a second or so to stabilise. That delay may not sound too much of a bigger deal, but it can be a bit of a problem when trying to find the hot spot in a beam that has travelled 10+ metres, or has been diverged with an additional lens such as Pangolin’s Safety Scan lenses. Measuring the weaker beamlets of a diffraction grating can also be a bit of an issue, especially as you get to some of the higher orders.

So if you want to measure emissions for audience exposure conditions you generally need to have something more sensitive that can also react quickly to finding hot spots in the beam. This is where photodiode detectors have the advantage over thermal detectors, for as you move them around the beam profile, their output is instant. Their downside is that they can’t measure high power beams, (without attenuation optics), and the big hassle… they are very wavelength dependent. You have to dial in a correction factor, (usually disguised as the wavelength value), in order for the meter to give the correct reading of actual optical output. When measuring multiple colour beams, each wavelength has to be measured one at a time, correcting for each wavelength, and then summing together to get the total power.

For audience exposure assessment you don’t need to be able to measure high power levels at the detector (unless you are a kamikaze laserist that wants to fry retinas!). What you are really looking for is a detector that works well over a range of a fraction of a mW through to several hundred mW. Remember, the MPE for a static beam for accidental exposure is 25.4W/m^2 (which is 2.5mW over a 10mm x 10mm area, or 1mW through a 7mm diameter detector). This is the highest limit you should be using if you do not have a scan fail monitor on your product that you know the characteristics of. If you do have a monitoring device, or can justify by other means why higher exposures are acceptable, then you are only likely to increase the irradiance at the audience by a factor of 4-10 times the 0.25s MPE limit.

Coherent’s Lasercheck is quite a good little photodiode meter for doing this.

I’m afraid at the moment, I’m not really familiar with how well Laserbee performs for safety assessments. The thing that stands out looking at the specifications is that it may not go down low enough for some types of audience scanning / exposure assessment. Being thermal too, it will take a little time to react to changes in light levels. But the positive is that it will not need to factor in wavelength changes. I’ll contact the makers to see if they can comment on the performance at the bottom end of the scale, which is where it is critical for audience exposure assessments.

James

[steviobee]

Thank you James, I will await your/their reply..

Someone needs to make something easy to measure this sort of thing!! ;-)

Coherent’s Lasercheck is quite a good little photodiode meter for doing this.

I’m afraid at the moment, I’m not really familiar with how well Laserbee performs for safety assessments. The thing that stands out looking at the specifications is that it may not go down low enough for some types of audience scanning / exposure assessment. Being thermal too, it will take a little time to react to changes in light levels. But the positive is that it will not need to factor in wavelength changes. I’ll contact the makers to see if they can comment on the performance at the bottom end of the scale, which is where it is critical for audience exposure assessments.

James