BlueAcro SQ-500 PAR sensor Arduino interface

ClownWrangler

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Has anyone here used the Arduino SQ-500 PAR sensor interface from blueacro? I thought the price was a bit steep ($37 shipped) for what it is, but bought it anyway to save time on my PAR meter project. Ordered it Monday but it hasn't shipped yet. I don't see any sort of documentation for it on the website either.
 
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Has anyone here used the Arduino SQ-500 PAR sensor interface from blueacro? I thought the price was a bit steep ($37 shipped) for what it is, but bought it anyway to save time on my PAR meter project. Ordered it Monday but it hasn't shipped yet. I don't see any sort of documentation for it on the website either.
Hmmmm what question do you have?
Sensor wires are color coded.
One lithium coin cell needed (2032) to run the amplifier.
Plugs directly in the VOM banana jack ports.
Labelled as to which.
My meter is set to 200mV range and obviously a different sensor (way more than .01mV per 1 PAR but for example).
0.01 mV per μmol m⁻² s⁻
.01 x 100 = 1mV = 1 "par"
131 mV = 131 "par"

Simply plug in the Amplifier to your multi-meter, connect the sensor to the terminal block, turn on the amplifier, and switch your multimeter to the 2V or millivolt range to read PAR on the display. If you are using the 2V range, simply ignore the decimal point.

Amplifies 10uV (microvolt) signals to milli-volt signals (100x gain)


.
paramp.JPG
 
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ClownWrangler

ClownWrangler

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Hmmmm what question do you have?
Sensor wires are color coded.
One lithium coin cell needed (2032) to run the amplifier.
Plugs directly in the VOM banana jack ports.
Labelled as to which.
My meter is set to 200mV range and obviously a different sensor (way more than .01mV per 1 PAR but for example).

.01 x 100 = 1mV = 1 "par"
131 mV = 131 "par"






.
paramp.JPG

I got the Arduino interface version. I sent an email today and got a shipping notice, but no info on the coding for the I2C interface. Ill just have to wait until I get it, ID the Chip and find a datasheet for the ADC. I was having trouble deciding on the version you have or the later and decided on the ADC version so I could make a dedicated meter and data logger. Also, with the version you have, you need to multiply the reading by the correction factor for under water measurements manually, which could get tedious.

https://www.apogeeinstruments.com/underwater-par-measurements/

You need to multiply your meter measurements by either 1.25 or 1.32 for imersion effect depending on the SN of your sensor. See page 16:

https://www.apogeeinstruments.com/content/SQ-500.pdf
 
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theatrus

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ClownWrangler

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Welp thats my bad.

The clearest example is the sample Arduino sketch:


Thank you. The code threw me off at first because my brain was in MATLAB mode with functions being at the end of the scrip. Lol. I see what's going on with it for the most part with the I2C library and main loop, but what's going on with the communications to the device is a bit esoteric without comments in the code. Some comments would make it bit more useful as an interface guide.
 

theatrus

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Thank you. The code threw me off at first because my brain was in MATLAB mode with functions being at the end of the scrip. Lol. I see what's going on with it for the most part with the I2C library and main loop, but what's going on with the communications to the device is a bit esoteric without comments in the code. Some comments would make it bit more useful as an interface guide.

Point noted - this was a very early product and it hasn’t kept as much care and feeding :)

The brains of the adapter are a MCP3425, so all of the I2C setup is mode setting the ADC:

 
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ClownWrangler

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Point noted - this was a very early product and it hasn’t kept as much care and feeding :)

The brains of the adapter are a MCP3425, so all of the I2C setup is mode setting the ADC:


Thank you. I ordered the Arduino interface version but was on the fence about the analog version because I'd like to be able to see how much ripple makes it through the sensor and amplifier section of the circuit with PWM dimmed lighting. I'm presuming a low pass filter is incorporated. Is this something you have analyzed? Is it a non issue for sampling in terms of aliasing, sample rate ect?
 

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