What connector on ophir 20c-a-1-y

[badger1666]

Any know what the connector type is on the ophir 20c-a-1-y please

Thanks

[White-Light]

4 pin Molex I believe:

http://www.ophiropt.com/laser/pdf/20...-A_20C-UAU.pdf

HOWEVER, most sensors off ebay and the like seem to come with bare wires ie minus the plug.

I also found out that some ebay sensors despite saying new are actually factory reconditioned units - they're as good as new but if you contact Ohir support with the serial number you'll typically find (if you have one of these) that it corresponds to an older sensor, possibly from the 90's) and Ophir will confirm the re-conditioning. I found this out from a friend who bought one and then spoke to Ophir. So far as I know the one I bought was new as I used a supplier many people have in the past on here, but you never know unless you get them direct.

[The_Doctor]

I looked at pictures not believing it was a simple Molex but it is.

Anything special to commend these heads? Cheap, widely available, or some other thing? I ask because I came up with a fast response circuit for a Scientech 360001 (I think..) head I got off eBay. I never made much of that circuit here because I didn't think there were lots of cheap heads it might be made to work with. This one might be a contender. I want to avoid making them because it's expensive and I don't have access to machines to make it easier or cheaper.

If I could do it economically, I'd make a few meters to sell. I'm sure that at least 5% accuracy can be had much more cheaply than it usually costs. The sticking point is cheap heads, and of course good calibration..

[White-Light]

I had one of these and these are the ones that Laserbee uses on some meters and others sell as well I believe.

They are widely available on ebay for around £150-200.

From my limited experience, they seem accurate and good high power heads for power measurement. As I said elsewhere, they lack the sensitivity for MPE measurement though as as the minimum measurable power is 20mw + /- 3%. So for power measurement yep they seem good heads. For MPE, they're not really suitable.

[The_Doctor]

Good point. They look like they could do with a cowl of some kind fitted to the front, ideally one that either absorbs (as in that on the heavy bodied Scientech heads) or perhaps reflective, in which case they could be cheap and light weight, though maybe risky to use in presence of strong beams. Yet another possibility is a thermally insulating cowl that blocks heat for long enough to get a reading. Toilet roll? A tad bit Blue Peter, but if it even looks like working it hints at a cheap way round the problem.

My Scientech head based meter will jump if I wave my hand in front of it so I doubt sensitivity is an issue there! I might get an Ophir head, but I haven't got much money so it's not a priority.

[White-Light]

Its not the absorption but the sensitivity for MPE purposes so screening the front won't help. I believe from the document the Ophir can handle 4W un-heat sinked or 20W heat sinked so its a great general power meter head.

The issue is for MPE you need to be measuring below 10mw where the minimum sensitivity here is 20mw.

I had a conversation about this with Bill Benner a short while ago and he advised me to go for a head with 1mw sensitivity or less. He also advised not to worry about the laser being more powerful than the head as you can measure beams individually for power purposes and once you have it bam'ed below the combined output limit, switch to white for MPE adjustment.

I have found a solution I think, although this is now deviating away from Chris's thread which I don't want to do, so suffice to say the meter is £300 but the head £500. However, I'll post details in a separate thread if it comes to anything. Either way, it sounds like a solution that's going to be too rich for many people even at that bargain price.

[The_Doctor]

Ok, but what makes that sensitivity? If they're basing it on system SNR, then reducing thermal noise might allow more sensitivity. That was my reasoning, but it's based only on my efforts with that Scientech head. For MPE it might be worth using something like a lasercheck or other silicon sensor. While not accurate without wavelength calibration the deviation of 200% or so across range might still be less objectionable if it's telling you that whatever it senses is 20% below max MPE. On the other hand if multi-wavelengths confuse the hell out of it (which I bet they do), then all bets are off. I'm getting off-topic and out of my depth too so I'll stop there.

[JStewart]

MPE measurement suitability aside, one of the limitations with this detector is the dynamic range that Ophir's built-in detector amplifier has. According an Ophir FAE, it is usually in the range of ~30:1, or 50:1 at best. To measure from several mW through to 5W requires multiple amplifier ranges to be implemented at the detector.

James

[lasersbee]

Those 20c OPHIR heads use a 4 pin Molex connector.
In a pinch you can use one of these .1" spc single row
female connectors but it won't be keyed...

http://www.ebay.ca/itm/10-Pcs-1x4-Si...item5d34a2eaf1


Jerry