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Ophir 20C-A-1-Y LPM PCB - Kits Available

loreadarkshade

loreadarkshade

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Dec 14, 2020
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This circuit was directly copied from my Ophir 20C-A-1-Y laser power meter head.
It will provide a reliable analog 1mV / mW output signal from any TEC cell or other sensor.
Calibration will be needed after building the LPM.

I am selling these PCB board kits with all the required components for those of you who don't want to do it yourselves.
$35 + $10 shipping to USA, $20 for international shipping (overseas). Send me a DM or leave a comment.

Please note this circuit is designed for a low output signal TEC.
Using a higher output signal TEC will require changing out R3 to a lower value. (ex. 100k)
The higher R3, the more sensitive the circuit is. the lower R3, the less sensitive the circuit.

Component list:
C1 - 1uF Ceramic Capacitor
C2 - 10nF Ceramic Capacitor
C3 - 1uF Ceramic Capacitor
C4 - 1uF Ceramic Capacitor
C5 - 1uF 63v Film Capacitor
C6 - 1uF 63v Film Capacitor
R1 - 1.126k ohms Resistor
R2 - 8.87k ohms Resistor
R3 - 1.6M ohms Resistor
R4 - 1.208k ohms Resistor
R5 - 391.1k ohms Resistor
R6 - 99.7k ohms Resistor
R7 - 300.6k ohms Resistor
P1 - 2k ohms Trimming Potentiometer - GAIN (Calibrate the LPM)
P2 - 25k ohms Trimming Potentiometer - OFFSET - Zero offset (set LPM to zero with this at thermal equilibrium)
P3 - 500k ohms Trimming Potentiometer - Unknown function
U1: OP07E Operational Amplifier
U2: TL081CP Operational Amplifier (interchangable with CA314OE)

I do not own any rights to this circuit. This is for educational purposes only.

ophir_wiring2.jpgOPHIR 20C A-1-Y heads and are calibrated to 1VW analog only output.jpgoAkTQLn.png
3.png1.png2.png
 

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loreadarkshade said:
This circuit will provide a reliable analog 1mV / W output signal from any TEC cell or other sensor.
Calibration will be needed after building the LPM.

Use this circuit to DIY a precision laser power meter for extremely cheap by combining this circuit with a TEC peltier cell for under $20.
I will also be selling these PCB board kits with all the required components later in this thread for those of you who don't want to bother ordering PCBs.
The full parts list is currently unknown and incomplete, to be added later to this thread.

Component values: (some are currently unknown)
c1 - 1uF
C2
C3 - 1uF
C4 - 1uF
C9
C10
R1
R2
R3
R4
R5
R6
R7

Potentiometers:
GAIN - Calibrate the LPM using this
OFFSET - Zero offset (set LPM to zero with this at thermal equilibrium)

Op amps:
U1: OP07E
U2: TL081CP (interchangable with CA314OE)

I do not own any rights to this circuit. This is for educational purposes only.

View attachment 76105View attachment 76099View attachment 76100View attachment 76101View attachment 76102View attachment 76103View attachment 76104
Click to expand...
If you want to I would be more than happy to lay out the PCB for you myself, especially since this is going to be an open source style project. I can see a lot of optimizations that can be done along with typical PCB design implementations especially considering this is going to be measuring mV-uV.
 
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Giannis_TDM said:
If you want to I would be more than happy to lay out the PCB for you myself, especially since this is going to be an open source style project. I can see a lot of optimizations that can be done along with typical PCB design implementations especially considering this is going to be measuring mV-uV.
Click to expand...
That would be great! :D
 
I had received the PCBs in the mail, there were a few mistakes.

The PCB thread pictures and component values have been updated to the correct circuit.
I will post again when I receive these new PCBs and test them.
 
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Success!! The circuit works. PM me for those of you who want to order a kit.
$35 shipped to USA, $10 extra for international shipping overseas.
 
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Due to increasing prices of one of the op-amps in the circuit costing itself $10, I had no choice but to charge $10 for USA shipping for all new orders.

Visit my website to purchase a kit:
www.jlasers.org

JLasers - LPM PCB Kit

Ophir 20C-A-1-Y LPM PCB Kit
www.jlasers.org www.jlasers.org
 
I still have a few hanging out somewhere if you're interested. The PCBs, not the actual sensor or metal body
 
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