Hyperion LPM + Vritonuzz Data Logger Platform

[paul1598419]

This is not a new idea as my S310 Scientech can be used with a calorimeter that comes with a resistor installed at the factory at the time of manufacture. It can't be retrofitted. I think there might be something you are overlooking in this design, though I am not entirely sure. Even with a SMD resistor mounted to a TEC, the amount of heat transferred to the sensor may not be the entire heat from the resistor as the resistor is still three dimensional and you only measure the heat produced by the resistor in contact with the TEC. There will be wasted heat getting away from the senor, unless I am missing something.

 

[Benm]

You are absolutely right to state that there are errors in this approach, if you are looking for a precision meter.

What i want to do is create a meter that has three aspects:

- reproducible measurements, good for comparing lasers to eachother
- reasonably accurate power measurement without a calibration source
- acceptable speed of measurement

On a budget there will always be a compromise, especially when it comes to the latter two points. By using comparison to a heating resistor you sort of solve both in one go: just matching the heater power to the laser input helps deal with waiting for things to stabilize, and also provides a simple (albeit not uber-precise) measure of absolute power.

I'm not suggesting the results would be spectacular by any means, but i don't think they need to be for most people that are working with lasers as a hobby. If you can get a 10% accurate power reading in 10 seconds on a device that costs $50 or so in hardware, wouldn't that be nice?

Certainly $500 would get you a nice sensor head with much faster response time and factory calibration, but that is quite a lot of money, probably more that -most- people spend on a single laser pointer ever.

I think it can be done with just an arduinos built-in ADC's to some degree, since the heating power is the square of the heating voltage, giving it logarithmic accuracy. With a 10 bit adc you could measure 1mV to 1V heater voltage steps, which would equate to 1 uW to 1W heater power in a 1 ohm resistor. This could greatly reduce cost while giving usable resolution in both high and low power ranges. Ideally i'd see it do something like 1mW to 5W in steps that are <1 mW at the low end and perhaps 10 mW at the 5 watt end, much like a 3.5 digit multimeter.

 

[paul1598419]

I was thinking that you might be able to get a better than 10% accuracy if you used a known power laser to compare to the resistor's measured power and use that as a template to use for the rest of your meters.

 

[Benm]

You would, but i'd like to create something people can use without having any laser of known power output available.

The 10% is just a fairly arbitrary goal though, it could end up being better or worse once the product is actually built and can be compared to calibrated equipment.

To me the most important aspect is that you can built the entire thing out of commonly available parts (except for the coated sensor tec's, there seems to be no way around that) - just things like standard opamps, transistors, resistors and such.

I have no commercial interest here at all though, and just want to make it open hard and software.

This should not be much of a problem with the Hyperion product line either - since that is a complete unit you buy and not something you have to solder and assemble by hand and could still come with pre-programmed sensor sensitivity parameters and such.

The most important common interest is getting a reliable source of coated TECs to use for both ideas. These are not commonly available items though, and it could help to create a demand for them to entice a producer to do a large-ish run of them.

Realistically no company is going to make these things by the hundreds, but if the demand is tens of thousands it becomes more attractive.

 

[Astralist]

Thanks for your patience! i just had an illness i need to take care of, thus causing the delay.
okay back to the topic, the thread is updated, software is finished

@Paul: You can download the datalogger at post no #2, and see if it can be used on your scientech. You need to open the port config and see if it can read something from your scientech, should there something can be read, just paste the text here. i'm looking forward to your test.

@Benm: where should i send the sensor? did your friend has come to Indonesia and still in indonesia? if so, please PM me their address in here.

 

[paul1598419]

Thank you. I will do that soon. Hope you are feeling better. I'm dealing with my own health issues at the moment.

 

[Astralist]

Hi everyone! The thread is updated with all the specification listed (after doing all the characterization)!
Although i'm sure I've wrote down all the specification, please let me know if you want to know more.

BTW it's on sale now! Click here

Cheers! :beer:

 

[Benm]

Sorry for my late reply...

@Benm: where should i send the sensor? did your friend has come to Indonesia and still in indonesia? if so, please PM me their address in here.

They'll be heading out from Bali to KL in a few days, so i guess that's a missed chance. I might be in indonesia myself around january though, but i doubt I will be in Jakarta unless I need to be for flights... Perhaps i'll go to Java, but probably not west of Yogya.

I see you are sending them out now and it looks like a really good deal. If i'm flying over to indonesia i'll certainly meet up with a Balinese friend so you could ship it to his house.

How much would it be for the 'cuprum' version plus 1 or 2 extra sensors?

 

[Astralist]

Ooops! Sorry i think it's my fault because of my delay.

All these 3 months i'm doing experiment on the coating, and found that the best (highest damage threshold) is achieved by simple carbon coating on the surface of the sensor. And while doing the experiment, looks like the chemical got me good, and so goes the story lol.
Altough it's not very black compared to HPCVD carbon deposition, it produces at least 480W/cm² which other hobbyist LPM cannot achieve.

The price of Cu version is $75 without shipping cost, the extra sensor i can provide for free (the 10x10mm version) as a means of keeping my promise. Just let me know whether you want the sensor to be attached to the heatsink or not.

Btw, i'm afraid i cant sell or give you the 6x6mm version due to the online stock and price. check here

Noblesse Oblige!

 

[Benm]

I suppose the difference between the 10 and 6mm sensors is that the 10mm just have slower response time?

I'm impressed with the coating though, that's a pretty high damage resistance value - practically good enough to shine most diode lasers into using normal focussing optics set to infinity (though defcussing them to spread the heat won't hurt).

 

[Astralist]

Yes, it has slower response time, and also worst resolution because of small voltage generation. If you are going to read those slow sensor using 22-bit++ ADC, then there will be no problem.

Yes, it designed so that you don't need to defocus your laser, because 6x6mm can barely cover multi mode beam (usually you need to measure your laser with the beam positioned diagonally). If you need to defocus, make sure the fast axis don't grow for more than 6mm.

 

[Benm]

That's cool.

Maybe you could include a cylindrical lens of sorts that defocusses only on axis so it spreads the light to a more squary pattern allowing even higher power lasers to be measured.

I guess you'd have to compensate for optical losses in that, but if those are reasonably well know you might get away with hardcoding them in software as an option.

With such an approach you could probably to towards the thermal limits of the sensor itself instead of the coating burning off being the limiting factor.

 

[94Z28]

Mine is enroute and I am very excited to try it out. Reviews will follow afterwards.

 

[CaliKirk]

Mine is enroute and I am very excited to try it out. Reviews will follow afterwards.

I received my Argentum earlier this week and I am so glad there is finally a real low cost LPM out there, I missed out on the opportunity to purchase a Radiant x4 while they were available. The Hyperion is very easy to use, and has a very bright and easily readable LCD display. And the data logging program is great!

 

[94Z28]

I received my Argentum earlier this week and I am so glad there is finally a real low cost LPM out there, I missed out on the opportunity to purchase a Radiant x4 while they were available. The Hyperion is very easy to use, has a very bright and easily readable LCD display. And the data logging is awesome!

Yeah I stumbled on the radiant in my quest of hunting through forums for a low cost LPM then this one popped up and reminds me of radiant x4 but with more new age features so hopped on it. Looks legit and I am going to put mine in a project box for sure to protect it.

 

[Astralist]

@Benm:
Actually if we follow like what you said, we can just calibrate the sensor when cylindrical lens being applied (the lens must not have AR coating, for flat spectral rejection/reflection)
The thing is, i'm sure the lens itself will be expensive and if the lens is gone then you'll end up with miscalibration.
For now, the sensor's coating burning off can no longer being a limiting factor, only the thermal limit of the PN junction is still being a factor for now.
Higher power to be measured is impossible for coated surface, as the 6 watt represents peltier Vout saturation, which giving you extra skew (about -10%).
Except if you choose No.3 for coating options (see OP), it can triple the max measurable powe because the Vout from peltiers seems only 1/3 compared to coated peltier.


@94Z28:
Actually i have 3D printer in here, and it has three nozzle capable of creating three simultaneous (and continuous) color on the printed object.
I bought it specifically for creating host for this meter.
Sadly after about 2 (two years) i can't finished yet LOL silly me :crackup:, all the time spent on creating PCB, firmware, and software.
It's so difficult to build because all the hole, shape, etc not fit perfectly, expecially a hole for mounting a bolt. As expected for almost every things from china :banghead::banghead::banghead::banghead::banghead:
About a project board, maybe you can just use some acrylic housing? or maybe a simple blackbox housing.