pdxmonkeyboy Posted January 12, 2018 Share Posted January 12, 2018 So i was going to bite the $350 bullet and get an apogee sq-120 par meter even though that is a big outlay for something you don't use often. Then I saw just the bare sensor for sale and the description said "self powered"... wait a minute.. it converts light energy to electrical current?? A little bit of google and yes indeed, you can make your own par meter with a sensor and volt meter!! I heard but did not confirm that quantum actually has a tutorial on how to do it! So i havent tested against another par meter but yhe measurements seemed really.close.from.my last check. Anyways, you need the following: 1. one agogee sq120 sensor. this is the one designed to read artificial light. 2. a cheap volt meter. i went harbor freight free with coupon model and the readings are almoat identical to my professiinal $150 fluke meter..3. some kind of rod or tube to mount the sensor to. I used acrylic rod from tapp, cut it at a 45 and welded a small mounting plate to the end if it. So yeah... mount sensor, wrap most of the wire around your rod, cut the ends off the multometer leads and twist and tape them to the sensor leads (the clear wire just leave free). black to black, red to red. turn the multimeter on and turn the dial to 200mv. Multiply the number on the screen by 5 and that is your par. Sent from my SM-G930V using Tapatalk 5 1 Quote Link to comment Share on other sites More sharing options...
youcallmenny Posted January 12, 2018 Share Posted January 12, 2018 That's certainly one way to use a multimeter! Well played! Quote Link to comment Share on other sites More sharing options...
TheClark Posted January 12, 2018 Share Posted January 12, 2018 Awesome! Quote Link to comment Share on other sites More sharing options...
albertareef Posted January 12, 2018 Share Posted January 12, 2018 Well that is pretty straightforward! Didn't realize they sold the sensors separately. Wonder if you could figure out the USB conversion and get it to work with their app so you could have things like the auto adjust for submersion etc. Pretty slick! Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 12, 2018 Author Share Posted January 12, 2018 Here is the link... https://www.rapidled.com/apogee-sq-120-quantum-sensor/Sent from my SM-G930V using Tapatalk Quote Link to comment Share on other sites More sharing options...
Willapa Posted January 12, 2018 Share Posted January 12, 2018 Very cool! Some real macgyver action here.Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 12, 2018 Author Share Posted January 12, 2018 Well that is pretty straightforward! Didn't realize they sold the sensors separately. Wonder if you could figure out the USB conversion and get it to work with their app so you could have things like the auto adjust for submersion etc. Pretty slick!actually.. that is a great idea... i still have male USB ends from when i made my apex interconnect cables. I just dont know if i want my laptop near my saltwater tank. Sent from my SM-G930V using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
albertareef Posted January 12, 2018 Share Posted January 12, 2018 1 hour ago, pdxmonkeyboy said: actually.. that is a great idea... i still have male USB ends from when i made my apex interconnect cables. I just dont know if i want my laptop near my saltwater tank. Sent from my SM-G930V using Tapatalk Just need a long enough cable . Maybe the cat would volunteer to hold it for you Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 12, 2018 Author Share Posted January 12, 2018 so i read on the apoge website that the underwater correction for the 102 sensor is to multiply by 1.08. That is all their handheld sensor does to correct for underwater readings is ad 8% more par. Interestingly though, their high end par meter requires a 31% correction! I need to find out if their software will do a time weighted average for an individual location. That way i can tell when to lower the halides after the rapid 15% par decline in the first 3 months. Sanjay did a really great test of halide spectrum and intensity loss over time. He uses bulbs for over 3 years!! At any rate, after 5 minutes with the new meter i know i have to raise my lights just a tad. Sent from my SM-G930V using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
youcallmenny Posted January 12, 2018 Share Posted January 12, 2018 11 hours ago, pdxmonkeyboy said: actually.. that is a great idea... i still have male USB ends from when i made my apex interconnect cables. I just dont know if i want my laptop near my saltwater tank. Sent from my SM-G930V using Tapatalk Pff, what's the worst that could happen? 1 Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 12, 2018 Author Share Posted January 12, 2018 emailed apoge. no joy on creating your own usb connection. oh well. Sent from my SM-G930V using Tapatalk Quote Link to comment Share on other sites More sharing options...
albertareef Posted January 12, 2018 Share Posted January 12, 2018 1 hour ago, pdxmonkeyboy said: emailed apoge. no joy on creating your own usb connection. oh well. Sent from my SM-G930V using Tapatalk Bummer. Was worth a shot for sure. Sounds like the correction factors are pretty simple anyway so probably not a big deal at least on that point. Thanks for sharing! Quote Link to comment Share on other sites More sharing options...
youcallmenny Posted January 12, 2018 Share Posted January 12, 2018 Was it the right voltage USB? They vary and should be pretty easy to wire if it's the right one. Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 13, 2018 Author Share Posted January 13, 2018 Was it the right voltage USB? They vary and should be pretty easy to wire if it's the right one. its not that its the fact that my USB port is not a volt meter Sent from my SM-G930V using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
youcallmenny Posted January 13, 2018 Share Posted January 13, 2018 Oh completely misunderstood that. Gotcha. Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 14, 2018 Author Share Posted January 14, 2018 Oh completely misunderstood that. Gotcha.yeah i got their email and i was like... duh, why didnt i think of that. Its weird though, their USB meter must have some voltage converting chip in it or something?? i have thus reached the limit of my understanding of electrical currents. which is ok, i still know the par readings throughout my tank and adjusted my lighting schedule to provide a Daily Light Interval to match shallow coral reef in sprin g and fall (16 mol photons/day). which is about 350 par for 13 hours. Sent from my SM-G930V using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
youcallmenny Posted January 14, 2018 Share Posted January 14, 2018 (edited) Get a dc-to-dc converter cable? Didn't think I'd be saying, "It's easy!" to you anytime soon, but here it is. Trust me, I'm trained in all things electronics by uncle sam, what could possibly go wrong??? There's a componant level chip for this reason too, but you'd need to solder it. Edited January 14, 2018 by youcallmenny 1 Quote Link to comment Share on other sites More sharing options...
pdxmonkeyboy Posted January 19, 2018 Author Share Posted January 19, 2018 Get a dc-to-dc converter cable? Didn't think I'd be saying, "It's easy!" to you anytime soon, but here it is. Trust me, I'm trained in all things electronics by uncle sam, what could possibly go wrong??? There's a componant level chip for this reason too, but you'd need to solder it. sure it could be done..but i dont really NEED it to be done..Sent from my SM-G930V using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
albertareef Posted January 19, 2018 Share Posted January 19, 2018 10 hours ago, pdxmonkeyboy said: sure it could be done..but i dont really NEED it to be done.. Sent from my SM-G930V using Tapatalk C'mon... where's your sense of adventure! 1 Quote Link to comment Share on other sites More sharing options...
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