DIY Laser Power Meter

[roSSco]

Kick ass!

 

[turtlecannon]

I'd be interested in one board if there's enough interest for another batch.

 

[Dark_Horse]

Knimrod,
Payment and PM sent, Thank you very much! I can't wait. ;D
Dark Horse

 

[roSSco]

Knimrod,
Payment and PM sent, Thank you very much! I can't wait. ;D

ditto

 

[knimrod]

Thanks! Everyone's payment received. I'll do my best to get these mailed out by next Wednesday.

 

[knimrod]

I've updated the third post in this thread with information regarding the PCBs and future group buys.

turtlecannon: You're the first person on the list for the next group buy.

 

[Zarniwoop]

My sensor just arrived!
In case anybody is expecting one in the mail, here's how long this one took:
Ordered on 1/12.
Got notice of shipment on 1/23.
Arrived on 1/26.

Now to get started on it...

 

[roSSco]

Mine shipped on the 24th. I guess it will be here Monday. :-/

 

[knimrod]

My sensor shipped on the 22nd.. Still not here yet.

However, I did get confirmation and tracking from Express PCB that they have shipped the PCBs and they will arrive here on Tuesday.  

 

[roSSco]

However, I did get confirmation and tracking from Express PCB that they have shipped the PCBs and they will arrive here on Tuesday.

 

[Buffo]

Saw a link to this discussion on PhotonLexicon and decided that I just *had* to get in on this deal!

My lasercheck tops out at a watt, but I've got an argon that should be able to do a little more than that. Plus a lasercheck is lousy for measuring a multi-line laser anyway; a thermal meter is the way to go. And you can't beat the price for this DIY project, so I figure now is the time to build one!

knimrod, please put me down for *two* of your PCBs. I'll send payment as soon as I get your PP address. (PM sent as well.) Thanks!

Adam

 

[Zarniwoop]

Hey Knimrod...
There are two R4s in the parts list.  R3 and R4 are listed as 47K, then there's another R4 listed as 10K that I don't see on the schematic.  Should we scratch that line in the parts list?
-- thx.

 

[knimrod]

Hey Knimrod...
There are two R4s in the parts list.  R3 and R4 are listed as 47K, then there's another R4 listed as 10K that I don't see on the schematic.  Should we scratch that line in the parts list?
-- thx.

Yep.. Not sure how that happened. Remove the 10K resistor. I've updated the BOM.

Thanx!

 

[LarryQ]

Quick question Knimrod....
Some of the digital meters I've seen state that then can be powered off the same curcuit they are reading...

Others do not...

I assume that the need for some sort of reverse voltage protection is required to protect or isolate the power to the meter itself from the voltage it is reading.

Kenom told me that the meter used in his meters needed a seperate power source.
Not using one could damage the meter.

does your curcuit take care of that??

LarryQ

 

[knimrod]

Quick question Knimrod....
Some of the digital meters I've seen state that then can be powered off the same curcuit they are reading...

Others do not...

I assume that the need for some sort of reverse voltage protection is required to protect or isolate the poser to the meter itself from the voltage it is reading.

Kenom told me that the meter used in his meters needed a seperate power source.
Not using one could damage the meter.

does your curcuit take care of that??

LarryQ

There are several DPMs available from Digi-Key and I've also seen them on Ebay.  You would want a 3 1/2 digit LCD DPM with 1mV resolution (0-1999mV).  It would preferably operate with a common ground between the PS and the voltage being measured and on a 9V power supply.  I sort of envisioned that this amp would be most commonly used to interface to a multimeter.  However, I've had my eye on this Ebay item and it appears to be the perfect DPM for this project.  

Some DPMs don't like having a common ground with the power supply and the voltage being measured.  This is mostly true of the DPMs that run from a single supply.  The Jewell DPM I used in my prototype meter can use a bipolar supply and only then share the same ground.  The Ebay DPM we've identified for use with our DIY power meter project can share a common ground between the PS (9V) and the voltage being measured according to the seller and the installation manual I received from him.  

I'm trying to be careful about selecting the right components.

 

[Kenom]

Quick question Knimrod....
Some of the digital meters I've seen state that then can be powered off the same curcuit they are reading...

Others do not...

I assume that the need for some sort of reverse voltage protection is required to protect or isolate the power to the meter itself from the voltage it is reading.

Kenom told me that the meter used in his meters needed a seperate power source.
Not using one could damage the meter.

does your curcuit take care of that??

LarryQ

Larry, I did indicate that that was just a feature of the meter you have on that. I've found lots of other meters that also have the ability to share the power common. As a matter of fact all of hte meters i'm going to sell from now on are going to have that ability. I don't like having to come up with a completely different power source for the voltmeter.