DIY PAR meter, Yeah you heard me - Page 37 - The Planted Tank Forum
 
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post #541 of 731 (permalink) Old 05-03-2013, 08:18 PM
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Sorry if my last post was a little gruff, but I was pretty upset at the time. OK, so here's the deal. After testing the meter against known Finnex values on two different lights, I'm seeing the values are still 2 to 3 times as high as Finnex's published data. I purchased another DIY meter from a different builder here on TPT. Testing against the Finnex values the new meter was accurate to +/- 5%, I'd call that good enough. Now that I had something to calibrate to I decided to "fiddle with the pot" to my surprise to pot was already turned down as low as it could go. I'll give you credit in that it was reading 55 at 6" from the CFL, but as soon as you use a different source, the numbers begin to rapidly increase from reality. I called around and found a hydroponics shop that had an Apogee MQ200 that they said I could use in the store. We ran all three meters together with MH, T5HO, and CFL sources. Again your meter only gave decent readings with the CFL, but with the other lighting sources and your meter was again reading two to three times higher than both the "other DIY" meter and the Apogee. I guess I can't really be too upset if you intended this meter to be specifically used on that particular CFL configuration. I know now for a fact after my last posting that I am not the only one having this issue with the meter. I would like to encourage others who have the meter to compare it with a legit PAR meter and see what the results are. The thing that kinda burned me was that since the pot was turned all the way down, you either did not test the unit, or you tried to trim it down so that the high readings would not be as glaringly obvious. Again, I apologize for the derail and my prior rudeness. If you would please PM me your address I will send the meter back.
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post #542 of 731 (permalink) Old 05-03-2013, 09:21 PM Thread Starter
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DIY PAR meter, Yeah you heard me

Ok, send me back the meter and I'll refund you. Something is wrong electronically. The photodiode might be blown. It happens. I'm getting normal readings here against t5-ho bulbs. I'll pm you.

Ps. I just checked reading on my DIY led. Readings are dead on. Let me give everybody a tip, on any light sensor, when you're measuring up close to a light source like a bulb, they are wildly variable. You can have one measurement and move the sensor closer to the light by an inch! You can get double the reading. The angle of the sensor can vary the reading as well. Published readings from light manufacturers can be off as well. Take the tip for what it's worth.

For aquarists, the only reading that really matters is the reading on the substrate. That'll give you an idea how much you have and it's physically fixed. You don't need to eyeball the distance to the light.

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post #543 of 731 (permalink) Old 05-05-2013, 11:56 PM
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Could something like this be used with a little calibration:
http://publiclaboratory.org/tool/spectrometer

Always curious.
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post #544 of 731 (permalink) Old 05-06-2013, 12:43 AM Thread Starter
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Quote:
Originally Posted by jccaclimber View Post
Could something like this be used with a little calibration:
http://publiclaboratory.org/tool/spectrometer
nice find. I think you can if the software can output some value (number) based on the light, not just a graph but I don't see that capacity from my quick overview.


Last edited by mistergreen; 05-06-2013 at 02:09 AM. Reason: ....
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post #545 of 731 (permalink) Old 05-07-2013, 12:01 AM
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DIY PAR meter, Yeah you heard me

Mr. Mistgreen, if you recall I PM'd directly after receiving the par meter I ordered from you telling you it was reading too high as well. I bought in the same run as Xmas_one. We exchanged PM's but once I sent you pictures you somewhat passed off the issue as I had good growth. Maybe this was a bad batch, I don't know.

I would like the same offer as Xmas_one to send your meter back please. I still have the PM's from you if you do not recall.

Thank you
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post #546 of 731 (permalink) Old 05-07-2013, 03:19 PM
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Are any more available to purchase?
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post #547 of 731 (permalink) Old 05-09-2013, 05:16 PM Thread Starter
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I will make a few this weekend to sell. I checked up on the complaints on the returned meter. It is indeed a calibration problem. The readings are a bit high about (10 - 20 par ) but not 2x, 3x.
It turned out it's more accurate if I calibrate it against a high light rather than a low light value.

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post #548 of 731 (permalink) Old 05-09-2013, 05:23 PM Thread Starter
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New firmware with new outdoor function. The new total resistance is ~15.9K ohm instead of the previous 21K-27K.

Code:
// CLOSE ENOUGH PAR Written in Arduino 23 By MISTERGREEN
// for sunlight and indoor light
#include <math.h>
#include <LiquidCrystal.h> // modified by O2surplus to include correct LCD pinout for "CLOSE ENOUGH PAR Meter" V1.0
                           //  Code also includes provision for seial output of PAR values to a PC.
float average = 0;
float output_indoor = 0;
float output_outdoor = 0;
float factor = 0;
unsigned long time; 
int counter = 0;
// create the LCD
LiquidCrystal lcd(8, 7, 5, 4, 16, 2);
// set up backlight
int bkl = 6; // backlight pin

void setup() {
  time = millis();
  // set up the LCD's number of rows and columns: 
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("Indoor   Outdoor");
  pinMode(bkl, OUTPUT);
  digitalWrite(bkl, HIGH);
  // initialize the serial communication:
  Serial.begin(115200); // Max for Arduino Uno
}

void loop() {

  int sensorValue = analogRead(0);
  average += sensorValue;
  counter++;

  //every second or 1000 millis
  if(millis() > time+1000) {
    //corrections to fit par
    average = average/counter;

    if(average <= 560) {
      factor = 2.077;
    } 
    else {
      factor = 1.934;
    }
    float tempout = average * factor;
    //indoor fluorensence
    output_indoor = tempout;
    
    //add 10% to output for sunlight
    output_outdoor = tempout + (tempout * .10);

    // set the cursor to column 0, line 1
    // (note: line 1 is the second row, since counting begins with 0):
    lcd.setCursor(0, 1);
    // print the number of seconds since reset:
    lcd.print(round(output_indoor));
    lcd.print("   ");
    
    lcd.setCursor(9, 1);
    lcd.print(round(output_outdoor));
    lcd.print("   ");
    
    // send PAR data to the Serial output.
    
    Serial.print(output_indoor);
    Serial.print(",");
    Serial.println(output_outdoor);
    
    //reset timer & counter to get ready for the next second.
   time = millis();
   counter = 0;
   average = 0;
    
  }
  
  delay(5);

}


Last edited by mistergreen; 05-09-2013 at 06:58 PM. Reason: +
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post #549 of 731 (permalink) Old 05-10-2013, 02:12 AM
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Oooooh! New firmware. I'm going to re-flash mine and give it a try. Just as soon as I can pry it away from "ShrimpNewbie" Lol.

225 Gal, Glass "Reef Ready" w/ twin Iwaki Pumps & 2 Ocean Clear inline filters.Lighting- Custom built DIY 600 watt LED system, BlueFish "mini" Led Controller,iAqua Aquarium Controller , and a 20lb CO2 system w/ Milwaukee Ph Controller.
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post #550 of 731 (permalink) Old 05-10-2013, 11:03 PM
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thanks for all the hard work on these meters. i just wanted to add in that i found a cheaper source for the 2447 plexi. estreetplastics i ended up with a 6x12x1/8" peice for 7.15 shipped. im not sure if the larger peices would save you anything but for the person building one of these (myself) it would save 4$ or so.
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post #551 of 731 (permalink) Old 06-02-2013, 11:07 PM
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Pm

Pm u
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post #552 of 731 (permalink) Old 06-27-2013, 07:18 AM
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Hi Mistgreen, its a very long interesting thread and great effort, I read a few posts in starting, few at end few in middle.... and I wish to make one of these. Few questions before I plunge.

1. Is the acrlyic filter necessary for the cup?
2. Can I used it for mix of WW,NW,CW,Red,Rolay blue LEDs, without any concern?
3. Is a PAR meter compulsory if one is building, or do you have any ready made feed in values?


Thanks for your time.
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post #553 of 731 (permalink) Old 06-27-2013, 02:59 PM Thread Starter
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1. yes the filter is necessary. The data curve would be steep and won't fit the par data curve.
2. Any full spectrum (warm or cool) white light should work great. I would worry with one color light especially yellow and green light.
3. It's best if you can get your hands on a PAR meter to callibrate this against. All sensors will drift after long use anyways. But if you don't have a PAR meter, use the materials and firmware outlined and set the main resistance to ~15.9K.


Last edited by mistergreen; 06-27-2013 at 04:14 PM. Reason: +
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post #554 of 731 (permalink) Old 06-28-2013, 05:56 AM
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Thanks for the reply mistgreen.
I ll take a call once I am able to figure out the 1 and 3.

Cheers!
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post #555 of 731 (permalink) Old 06-28-2013, 08:39 PM Thread Starter
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Quote:
Originally Posted by saiko View Post
Thanks for the reply mistgreen.
I ll take a call once I am able to figure out the 1 and 3.

Cheers!
PM me, I can mail you a piece of the acrylic. I have plenty.


Last edited by mistergreen; 06-29-2013 at 01:40 AM. Reason: =
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