AliExpress 100mW 532nm surprise

Livinloud said:

Your LPM reads 0.0988 so I think you put the decimal in the wrong place :crackup:

Never understood the desire to make 1.000 = 1000mW. IMO they should read 1000.0 = 1000mW but that's just me

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I read it this way:

1.0000v = 1W
0.9999v = 999.9mW
.
.
.
0.1000v = 100.0mW
0.0100v = 10.0mW
0.0010v = 1.0mW
0.0001v = 0.1mW

So, the 0.0988 is 98.8mW, or are you saying my 100mW greenie is only 9.88mW or is it 988mW?

:thinking:


-Bob

This is starting to confuse me hahaha

I didn't build the LPM so idk how you set it up. All I was saying is I've seen people do the 1.0000 as being 1000mW and to me that's just funny looking. As you see with yours it shows up 0.0988 and to me, visually, that looks like well congrats you didn't even make it to 1mW. I personally like my LPM to read 1000 when I hit 1000mW, 100 when its 100mW, etc.....

Again I cant speak on your LPM since you built it and you should know how you built it.

ryanr256 said:

I recently purchased a 100mW 532nm pointer from AliExpress (seller Luck Shop).

free shipping lowest price high quality 5000mw Handheld Adjust Focus green / red Laser Pointer SDLaser 302-in Laser Pointers from Office & School Supplies on Aliexpress.com

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Also I noticed that you said you bought a "100mW" laser but your link says otherwise.

Mine's also set up as 1.000 = 1W. But that's also because the DPM can also be used to measure internal battery voltage or external input

Yeah I know its a common thing but its just something small that I personally don't like. I don't have to deal with it since I have a Rubicon but it seems a very common thing with DIY LPMs. Its not something anyone did wrong, I think its just the only way the parts work together.

Easier to understand that 1.000 = 1.000W. Watts is the "parent" unit, modified with prefixes.

Livinloud said:

I didn't build the LPM so idk how you set it up. All I was saying is I've seen people do the 1.0000 as being 1000mW and to me that's just funny looking. As you see with yours it shows up 0.0988 and to me, visually, that looks like well congrats you didn't even make it to 1mW. I personally like my LPM to read 1000 when I hit 1000mW, 100 when its 100mW, etc.....

Again I cant speak on your LPM since you built it and you should know how you built it.



Also I noticed that you said you bought a "100mW" laser but your link says otherwise.

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The Ophir is a 1mV = 1mW sensor, correct? I looked but I could not find any specs on the resolution of the device.

The VM display I used is this one:

Yellow LED 5 Digit DC 0 4 3000 33 000V Digital Voltmeter Voltage Meter Car Panel | eBay

It's a 5 digit 0V to 33V display. As shown in the picture it reads down to .0001V. "milli" is expressed as 0.001, or 10^(-3). In this case there is an extra digit in my display.

I don't think there is any manipulation of the signal from the Ophir to the display, but I'd have to ask Jerry to be sure. I am using his OPHIR-S power rail.

I didn't realize there is a standard for LPMs. If I had known I would have adhered to it and there wouldn't be any confusion.

Oh, as for the laser, yes, the title is very misleading, as most of them are. But, if you go to the actual page, in the "Product Description" section there's an entry for "Laser Output". That's where it states that it's an "100mW" laser.

Considering it measures 98.8mW, as pictured, I'd say it's pretty accurate (the ad for the laser). Due to technical issues, I don't yet have data logging for my LPM yet so I can't provide any graphs. I'm hoping to have my issues resolved soon though.

-Bob

Good luck contacting him, haven't seen him on the forum is two months. To tell you the truth its been a quieter less argutive place when it comes to LPMs......kinda like it. I hated the arguing thatvhe would always get into. It was a pissing match on how his LPMs were "better" than everyone else's and then better ubita became mass available and he ran. Could be hard at work on a better ubit or could be mad that hobbyists showed him up, who knows

I just ordered a 5digit voltmeter recommended by ARG. the one I originally had needed to be adjusted for reading under 1w or over 1w if you wanted any kind of accuracy. Hopefully ARG recommended a good one. He is the man to see about a lpm

Livinloud said:

Good luck contacting Jerry, haven't seen him on the forum is two months. To tell you the truth its been a quieter less argutive place when it comes to LPMs......kinda like it. I hated the arguing thatvhe would always get into. It was a pissing match on how his LPMs were "better" than everyone else's and then better ubita became mass available and he ran. Could be hard at work on a better ubit or could be mad that hobbyists showed him up, who knows

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I'm well aware of Jerry and his actions on the site. He had what I needed/wanted and I felt it was a decent price. I could have built it myself, but I no longer have as much free time as I used to so it's easier for me to assemble pre-built components. Same thing with the Isis board. I could have built one using Arg's (and Trevor's) instructions, but it was easier for me to get one of the pre-built units.

I don't have a way of reliably testing the display for accuracy, other than comparing the readings with a DVM I've had and used for years. Maybe I'll do that when I get bored this weekend.

-Bob

I hear you on the time vs price of pre built. Most times I go with prebuilt too

ryanr256 said:

I could have built one using Arg's (and Trevor's) instructions, but it was easier for me to get one of the pre-built units.

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This. I hate seeing people jabber and stab and send sneaky posts and messages, when really, both projects are very different! One is "pay money, get device," one is considerably more work, but cheaper.