ARGMeter Open Source - Coming Soon

Re: ARGLPM Open Source - Coming Soon

There's a jumper on the board to select which sensor to use if it is being used with both.

I've been looking into those switched capacitor IC's to make this all run off of 5V, it's amazing they can put all that into a SOT-23.

Re: ARGLPM Open Source - Coming Soon

PCB is a week away. I'm about to do an order from Digikey if you want one and you're not already on my list let me know and I'll buy more parts. No commitment or anything, this is just to get a feel for how much I should buy.

brucemir - TEC
rbc1225 - Ophir
n2stuff - TEC
SpyderFire - TEC
awillis2589 - Ophir

Everything is ready to go pending the V2 boards. Once I have both an Ophir & TEC version made & tested it will be released

Re: ARGLPM Open Source - Coming Soon

Is that the one with both TEC and Ophir support or is each specific to a type?

I'm interested, specially if you can sell me cheaper just the TEC + callibrated shield, without the Arduino, USB cable and battery cable. Got more Arduinos than I need around here

Re: ARGLPM Open Source - Coming Soon

ARGLaser said:

PCB is a week away. I'm about to do an order from Digikey if you want one and you're not already on my list let me know and I'll buy more parts. No commitment or anything, this is just to get a feel for how much I should buy.

brucemir - TEC
rbc1225 - Ophir
n2stuff - TEC
SpyderFire - TEC
awillis2589 - Ophir


Everything is ready to go pending the V2 boards. Once I have both an Ophir & TEC version made & tested it will be released

Click to expand...

Add me too Seoul_lasers - Ophir :beer:

Re: ARGLPM Open Source - Coming Soon

Seoul_lasers said:

Add me too Seoul_lasers - Ophir :beer:

Click to expand...

Done! :beer:

Atomicrox said:

Is that the one with both TEC and Ophir support or is each specific to a type?

I'm interested, specially if you can sell me cheaper just the TEC + callibrated shield, without the Arduino, USB cable and battery cable. Got more Arduinos than I need around here

Click to expand...

It supports both if it is equipped with the parts for both, there's a jumper that will make the TEC input go to the amp.
The idea behind the design was such that there would be one PCB for both versions.

Edit: The first unit is for sale here. It's a one-off unit.
http://laserpointerforums.com/f39/fs-3w-lpm-w-datalogging-125-a-80284.html

Re: ARGLPM Open Source - Coming Soon

ARGLaser said:

Done! :beer:



It supports both if it is equipped with the parts for both, there's a jumper that will make the TEC input go to the amp.
The idea behind the design was such that there would be one PCB for both versions.

Edit: The first unit is for sale here. It's a one-off unit.
http://laserpointerforums.com/f39/fs-3w-lpm-w-datalogging-125-a-80284.html

Click to expand...

I'm not sure how much effort you have put into testing with the Ophir heads, but you may or may not be aware that there are differences that can greatly affect accuracy. The hobby users of these Ophir heads may not be aware of these differences and how much the accuracy can be affected by the applied power supply voltages.

With the 150C-A-x-x series, they require + and - power supply of 12V to 24V and that is internally regulated to pre-calibrated precision voltages to maintain output precision. Input voltages can vary greatly, and as long as they are within the regulator input range, the output readings will be accurate as long as the Ophir head is still within calibration.

With the 20C-A-x-x series, they require an externally regulated + and - power supply of 5V to 18V. There are NO internal regulators, therefore output precision is FULLY dependant upon power supply regulation and balance. Just millivolts of variation in balance between the + and - power supplies can equate to milliwatts in variation in output reading. The higher the applied optical power/output reading, the greater the measurement error. For this reason, any power supply intended to operate a 20C-A-x-x series Ophir head should implement a precision pair of regulators, preferably with fine voltage adjustments for balancing these supply voltages. If your Ophir head reads any offset from 0.000 volts upon cold powerup, you are likely experiencing some effects of voltage imbalance, or there may be a callibration issue. Any readings taken under those conditions may be suspect.

Edit: Forgot to add, the noise figure for the Ophir 20C-A-x-x series is 0.5mW and minimum power rating for calibration purposes is 20mW. What this means is any reading steps of less than 0.5mW can be buried in the noise. I use 1mW steps for my own LPM that uses the Ophir 20C-A-1-Y.

I hope this helps.

Bob

The LPM's will only be compatible with the 20C-A series. The IC generates a +/- from the battery so if the batter reads 9.2V, each rail will read +9.2V and -9.2V, both rails read the exact same so it's good for use with the Ophir heads.

ARGLaser said:

The LPM's will only be compatible with the 20C-A series. The IC generates a +/- from the battery so if the batter reads 9.2V, each rail will read +9.2V and -9.2V, both rails read the exact same so it's good for use with the Ophir heads.

Click to expand...

What IC are you referring to...:thinking:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

ARGLaser said:

The LPM's will only be compatible with the 20C-A series. The IC generates a +/- from the battery so if the batter reads 9.2V, each rail will read +9.2V and -9.2V, both rails read the exact same so it's good for use with the Ophir heads.

Click to expand...

Sounds good and I certainly mean no disrespect to you or anyone else here. I'm an engineer and I was just offering some of my knowledge and experience as related to these products. It sounds like you are using a pair of isolated output DC/DC converters in series with the common brought out, operating from a single common input. I've used these myself, but I have always followed with adjustable regulators on the outputs because every device has slightly differing tolerances that can cause minor variations in output. Typically not as much as tenths of a volt, but hundredths or thousandths of a volt are fairly common.

Have you checked these voltages down to the thousandths of a volt (mV), ie 9.2xxV? An imbalance of even 0.001 volt can affect the readings by more than the noise figure alone. The percentage of error would be low of course, well within the acceptable range for a hobby user. Where it really starts to be an issue is when the imbalance creeps up to hundredths of a volt or more and you're metering lasers with powers of several watts. I have seen as much as 500mW of error in multiwatt laser power readings with several tenths of a volt of power supply imbalance on these things. The amplifiers built into these Ophir 20C-A heads are affected by both voltage balance and power supply noise/ripple.

To put it simply, they were just not designed to be used within the electrical operating environments that most hobbiests are using them. They are precision measurement devices designed to be operated within a precision electrical environment. Because there have been very few of these reported to have been damaged by mismatched voltage inputs at the hands of hobbiests, greatly attests to the ruggedness of these devices. Well done Ophir!

I really love what you have done here with the LPM and Datalogging projects. Well done to you too as well!

Bob

From what I read I don't think he is using a pair of isolated
output DC/DC converters.. That's why I asked which IC chip
he was referring to. After all this is supposed to be an Open
Source LPM so there are no secrets....:beer:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

lasersbee said:

From what I read I don't think he is using a pair of isolated
output DC/DC converters.. That's why I asked which IC chip
he was referring to. After all this is supposed to be an Open
Source LPM so there are no secrets....:beer:


Jerry

Click to expand...

hehehe I am sure it will be in there when the schematic is released to the public.

Bob_Boyce said:

Sounds good and I certainly mean no disrespect to you or anyone else here. I'm an engineer and I was just offering some of my knowledge and experience as related to these products. It sounds like you are using a pair of isolated output DC/DC converters in series with the common brought out, operating from a single common input. I've used these myself, but I have always followed with adjustable regulators on the outputs because every device has slightly differing tolerances that can cause minor variations in output. Typically not as much as tenths of a volt, but hundredths or thousandths of a volt are fairly common.

Have you checked these voltages down to the thousandths of a volt (mV), ie 9.2xxV? An imbalance of even 0.001 volt can affect the readings by more than the noise figure alone. The percentage of error would be low of course, well within the acceptable range for a hobby user. Where it really starts to be an issue is when the imbalance creeps up to hundredths of a volt or more and you're metering lasers with powers of several watts. I have seen as much as 500mW of error in multiwatt laser power readings with several tenths of a volt of power supply imbalance on these things. The amplifiers built into these Ophir 20C-A heads are affected by both voltage balance and power supply noise/ripple.

To put it simply, they were just not designed to be used within the electrical operating environments that most hobbiests are using them. They are precision measurement devices designed to be operated within a precision electrical environment. Because there have been very few of these reported to have been damaged by mismatched voltage inputs at the hands of hobbiests, greatly attests to the ruggedness of these devices. Well done Ophir!

I really love what you have done here with the LPM and Datalogging projects. Well done to you too as well!

Bob

Click to expand...

No offence taken Bob, this is how things get improved

You are correct about the IC I am using, I've used a few of them and the rails are always within a hundredth of a volt of each other, usually a few thousandths. You're right about using regulators though, I should implement those.

From my own testing the readings will be skewed +/-.5% when the voltage difference exceeds +/-.2V which is acceptable for a hobbyist in my opinion, as these are calibrated to +/-3%
The zeroing, in my testing changed based on the input voltage to the Ophir head. From what I saw there was little connection between the zeroing and voltage difference. (couple tenths of a mV)
These results are from one head though, as I understand you have quite a few heads Bob, are they all like you have described above?

I sent you a PM, perhaps would you like a sneak preview of the schematic?

lasersbee said:

From what I read I don't think he is using a pair of isolated
output DC/DC converters.. That's why I asked which IC chip
he was referring to. After all this is supposed to be an Open
Source LPM so there are no secrets....:beer:

Click to expand...

There are a few IC's I'm currently testing, I don't want to say which IC it is yet until I know for certain which one is going in the design. It's not quite Open Source yet as I'm still working on some of the materials.

This is all great stuff guys. Just read thru every post in this thread. Nice to see how this is all coming together. Also just checked out Blords quick setup.
Thanks to all for posting openly so we can try and follow how this is playing out.
Greatly apreciated:thanks:

No problem Pman I talked this over with Bob some more in PM, and he verified the IC I'm using will be fine.

Here I was expecting to get PCB, instead I got all of this:


The PCB place messed up my order, badly. Worst part is that all of this adds up to 300$, so I had to pay 50$ tax at the door on top of the 60$ I paid for the PCB. Out 110$ and no PCB, fun.

Got:
20x Waterproof Temperature Sensor
5x SIM900 GSM/GPRS Minimum System Module
5x 8 Channel 5V Relay Module

This is what happens when you buy your PCB from China.

dang that sucks they better fix that. i take it that means we will have to wait a little longer?