Introducing Radiant Electronics and the Radiant Alpha Power Meter

I hope you get new LPMs before Christmas .. as I need to buy me some presents :umbrella:

My Radiant Alpha arrived today!
Thank you very much!

It seems to be fairly accurate. The Zeroing function sometimes stays around 1mw, I can adjust between 0 and 8mW with the zero pot, but if I'm stuck at 1mW I can't turn it lower. Nonetheless, I doubt I'll be measuring lasers in the 1mw range.

My 1W 445nM from Rayfoss came in at the numbers Faona sent me. 780 - 790 mW with the waterproof lens in place and 840 mW with the waterproof lense removed!

All my lasers check out what I was expecting, so this is looking pretty accurate.

Thanks again!

I'm curious about the upcoming product line

I hope you'll be able to offer higher power level meters. 2 watts seems to be a barrier that is easily crossed nowadays, even using single 445 nm diodes in some experimental setups.

Neutral density filters will not do that much good in thermal meters - any light they absorb is re-emitted as (deep) IR, and could throw off measurements if the sensor picks it up at all.

MrDave said:

My Radiant Alpha arrived today!
Thank you very much!

It seems to be fairly accurate. The Zeroing function sometimes stays around 1mw, I can adjust between 0 and 8mW with the zero pot, but if I'm stuck at 1mW I can't turn it lower. Nonetheless, I doubt I'll be measuring lasers in the 1mw range.

My 1W 445nM from Rayfoss came in at the numbers Faona sent me. 780 - 790 mW with the waterproof lens in place and 840 mW with the waterproof lense removed!

All my lasers check out what I was expecting, so this is looking pretty accurate.

Thanks again!

Click to expand...

Glad you like it. If the meter won't zero chances are there is an ambient energy source like warm air from a vent, your hands, sunlight, etc that could be causing a reading. I made sure that all the meters zeroed properly before packaging but it's difficult to give them a large zeroing range as the internal circuit does not have a negative voltage rail. This eliminates the need for noisy dc/dc converters, additional circuitry, and enables their low price but does have the side effect of making the zeroing more difficult.

Benm said:

I'm curious about the upcoming product line

I hope you'll be able to offer higher power level meters. 2 watts seems to be a barrier that is easily crossed nowadays, even using single 445 nm diodes in some experimental setups.

Neutral density filters will not do that much good in thermal meters - any light they absorb is re-emitted as (deep) IR, and could throw off measurements if the sensor picks it up at all.

Click to expand...

Yeah, these 445 diodes have really changed everything. Heck a year ago the cheapest meter here was a Laserbee I that only worked up to 1 watt for $200, and that's without an enclosure.

Higher capacity and datalogging will be definite features for upcoming products. :beer:



edit - also, 3000th post

mario,

I did notice the 15watt Flourescent desk lamp I have on my desk may have been the issue.

I had just thought that perhaps the adjustment would allow you to trim the meter to a (-) negative value like "-.003" but I have realized that all negative readings are displayed as "-.000". It seems that you can trim between "-.000" fully counterclockwise and about ".008" (+/- a couple mw) fully clockwise.

I have some Plastic tripod clip heads coming from Dealextreme
DealExtreme: $2.71 Universal Clamp Mount for Tripods (Holds up to 3.8cm Thick Objects)
to hold lasers that dont have the tripod screw mounts already in the Host, like my Rayfoss 200MW green pointer already has.

So I can set up the meter and the thermopile on a bench and the lasers about 6 inches away properly focused (Not to a pinpoint for burning lol) and rock steady.
This way I can stand much further way and keep all heat sources, including my body, away from the sensitive thermopile. In this manner I can always adjust the meter to ZERO. When it reads "-.000" the value it is reading is actually below zero and turning the adjustment knob clockwise I just go until I get a reading of ".000", This being the actual zero'd out calibrated reading. So yeah it is working great.

As a hobbyist power meter, I know that the measurements are not scientifically precise, meaning I wouldn't bet the lives of seven astronauts on a space shuttle mission on the accuracy of my laser power registered. But I would trust that I am very near the ballpark figure and within a few of milliwatts!

Some of my meters had previously been measured and others had values assigned to them. Everything seems to be close to expectations.

Great work MarioMaster and everyone else involved in producing this meter!

My meter came yesterday. Measured all 6 of my lasers twice and the readings were within 1-3mw. I was surprised my 6x was about 55mw more than I expected and my LPC was about 25-30mw under what I was hoping for. Time to get a better lens for it mehtinks.

MarioMaster said:

Yeah, these 445 diodes have really changed everything. Heck a year ago the cheapest meter here was a Laserbee I that only worked up to 1 watt for $200, and that's without an enclosure.

Click to expand...

Its a leap in output power for sure. Before the 445's a 1 watt meter would suffice to measure any single diode on the market, and even combinations of 2 diodes were not likely to exceed the 1 watt capacity.

Increased power does not have to be a problem though, as long as you can reduce the power using neutral density filters. I suppose a 1/10 ND filter made from glass will suffice up to several watts, perhaps allowing for a meter that handles 1 watt directly and 10 watts with the filter in between.

I suppose it will not be very long before we see 10 watt homebrew mutli-diode setups though. Knife edging several 445 diodes seems quite feasible, and if prices on those drop further i'm sure people will be buidling things like 8 diode units.

Hey I was out of town and had no internet over the holiday but I got my LPM and it works great! Thanks so much!

Radiant Electronics, Radiant Alpha Power Meter carry case

So I did a couple things this weekend.

First, I took out my P-Touch labler and put a power button and identifying nomenclature on my Radiant Electronics laser power meter.

Secondly, I bought a case to house my meter and protect it. The case was $14.99 at Fry's.

I think it turned out pretty well. As several of my lasers have hard cases I figured that my LPM might as well be just as protected.

I like the operation of this unit. I know its just the hobbyist grade, but so far it has proven to be accurate and reliable.

Thanks for your hard work in bringing this meter to market!

Re: Radiant Electronics, Radiant Alpha Power Meter carry case

Just got my Alpha in the mail today. And i love it. My 5mW ebay pen came in at 47mW. However my Dragon Lasers Viper 95 came in at only 86mW... i thought it would be overspec, although it is 3years old so i dont know if that does anything.

Glad everyone is happy with their meters

Also, I'm gonna try and get a small batch out this weekend so keep an eye out.

MarioMaster, Spyrorocks:

Even with the shipping dance due to the holidays I *did* get mine and it works just fine. Good to have another meter around. Though once you get the custom display options I may be interested again. I'll be watching your site.

I thought I'd pass this along as an FYI so hopefully nobody else has the near disaster I almost had while metering my 6x a couple days ago. I defocused the dot so I wouldn't damage the sensor but I didn't look to see where in the beam the focal point was. When I moved the laser forward a bit to keep the splash off the heatsink I saw the dot change from a light orange (though my glasses) to a bright white. Yup. The focal point was just in front of the sensor. I quickly moved it away but it still left a faint line across the sensor. It didn't burn though the coating so I got *really* lucky. From now on before metering a focusable laser I'll either take it into a dark room where I can see the beam and find the focal point or use a piece of paper to find it if I can't go to a dark location first.

If you're looking for the focal point in the beam look for the point where it does something like this:

=====>---<======

Somewhere in the --- part will be the "sweet spot" of the focal point that can do some serious damage to your LPM's sensor. Usually the beam will start to form a cone shape starting at the focal point which can make it easier to find. And as always be careful when working close to the aperture of any laser while looking for the focal point.

You should be able to just screw in the focus as far as it goes if your using an Aixiz and then back it out as necessary. This way there is no focal point and the beam will never get tighter than at the aperture so you dont have to worry about moving the laser around.

DrSid said:

With lasers this strong you must be very careful .. the ND filter may absorb those 87% of energy, rather then reflect it .. in which case it can be damaged by the laser (burned through in other words). And if it reflects all the light you mast be careful where it will reflect, as the reflection again can damage the diode if it enters the module again, or it can burn through your shirt or what whatever.

I have an idea. It would require another laser which power is withing the LPM range. Then you will need piece of clear flat glass, and some beam stop. Let's say we want 25% of the light. First you aim the laser at the LPM, and note the power. Now put the glass in between .. and rotate it. It should move the dot a bit, and the reflection/transmission will vary with the angle. Turn unless you obtain 25% value on LPM. Use the beam stop to 'catch' the reflection, or just make sure you know where the reflected 75% will end up.
Now just leave the configuration as it was, and replace the laser. Safe, cheap.

Click to expand...

The more I think about it the more I see this idea is genius. I took it a step further and might build an apparatus to increase accuracy.

Have an open top box. Mount the sensor inside it. in front of the sensor place a piece of glass on a mount that can rotate. then in front of that have a piece of wood or other material with a small hole in it and then in the side of the box have another small hole that creates a line from it through the whole in the wood piece, through the glass and onto the sensor.

What the holes would do is ensure that the beam entering the device is always straight on (to ensure accuracy) because it will only pass through both holes if it is. Using a laser within the power rating of the LPM you could rotate the glass until it reads 75% of the power of that laser with no glass and mark that position and and then again for 50% etc. This would allow for multiple ranges (A 2W LPM could have ranges from 2W to 4W to 8W etc) without having to recalibrate and carefully align everything every time! :drool:

Just attach the sensor, set desired range, measure and multiply readout accordingly!

Of course accuracy would fall if you try to go to very high ranges but should work great for even 8W at which point being off by even 200mW or so isnt much relative to the output :beer:

Braddubya said:

You should be able to just screw in the focus as far as it goes if your using an Aixiz and then back it out as necessary. This way there is no focal point and the beam will never get tighter than at the aperture so you dont have to worry about moving the laser around.

Click to expand...

That's not a bad idea. One thing I forgot to ask is there a recommended distance from the sensor you should place the laser? I've seen some people say 6" is good but I've sen videos of people putting them anywhere from point blank to a couple feet away. I would think point blank would be bad because the LPM's sensor would pick up heat from the host or your hand and throw the reading off.