reef-pi :: An opensource reef tank controller based on Raspberry Pi.

Bigtrout

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The pi runs fine on normal power so I think it's the loose connection. QEBIDUL LM2596S DC-DC Buck Converter DIY 4-40V to 1.25-37V Step-down Regulator Power Module Volt Stabilizer with LED Voltmeter Display
Id check all your connections and test voltage on the 5v and ground pins of the hat with a decent voltmeter. Just because the readout on the buck convertor says 5.1 volts doesnt necessarily mean its accurate.
 

AquaRaider44

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Id check all your connections and test voltage on the 5v and ground pins of the hat with a decent voltmeter. Just because the readout on the buck convertor says 5.1 volts doesnt necessarily mean its accurate.
It shows 5.2 output and 17.7 in. Not shutting off now with soldered wires but making autable noise
 

AquaRaider44

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Double check your proto circuit and make sure you dont have any inadvertent tie between the 3.3 and ground rails.
I don't see any.

IMG_20190503_190546.jpg


IMG_20190503_190508.jpg
 
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Ranjib

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@Ranjib
Did I read previously that the ph board is only going to have 2 point calibration at ph 7 and ph 10?
What does that do for anyone in freshwater who is looking at a below 7 ph?
If the logic of a 3 point calibration is too hard to implement, would it be possible to allow a choice in 2 point calibration one being ph7 and ph10 and the other choice being ph4 and ph7?
Im wondering about the accuracy in acidic conditions if the probe is calibrated for alkaline ph.
Yes,. you are right , we'll be supporting only two-point calibration. Its not because of just its hard to implement three-point calibration, I didn't find many documentation or documentation that can be generic enough for different types of probes. More, over its not clear if the proprietary three-point calibration techniques are basically two independent two-point calibrations or utilize some specific empirical coefficient. From my limited reading, my learning was one can fairly reliability use two-point calibration as long as the measurement range is within the calibration range (acidic or alkaline). The implementation I am doing for ph is not aware of the scale,. it only cares about expected and observed measurement. So, you can use ph 7 and ph 4 as calibration point and use it for freshwater tanks, or calibrate with ph7 and 10 and use it for marine tanks, or just use one point calibration. I am yet to discover the impact of this. I am approaching this systematically, currently charting the raw voltage, while taking a parallel reading using atlas probe+chip, swapping different probes (American marine and milawukee) with and without the calibration applied. I am also taking parallel readings hanna ph checker (the white electronice hand held device). I'll keep you posted. Meanwhile, if you have any suggestion, please do let us know here. It will be awesome if one of us start a thread on this in the chemistry sub forum. I am really enjoying exploring all these calibration, analog converstion, testing different probes part :)
 

Bigtrout

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Yes,. you are right , we'll be supporting only two-point calibration. Its not because of just its hard to implement three-point calibration, I didn't find many documentation or documentation that can be generic enough for different types of probes. More, over its not clear if the proprietary three-point calibration techniques are basically two independent two-point calibrations or utilize some specific empirical coefficient. From my limited reading, my learning was one can fairly reliability use two-point calibration as long as the measurement range is within the calibration range (acidic or alkaline). The implementation I am doing for ph is not aware of the scale,. it only cares about expected and observed measurement. So, you can use ph 7 and ph 4 as calibration point and use it for freshwater tanks, or calibrate with ph7 and 10 and use it for marine tanks, or just use one point calibration. I am yet to discover the impact of this. I am approaching this systematically, currently charting the raw voltage, while taking a parallel reading using atlas probe+chip, swapping different probes (American marine and milawukee) with and without the calibration applied. I am also taking parallel readings hanna ph checker (the white electronice hand held device). I'll keep you posted. Meanwhile, if you have any suggestion, please do let us know here. It will be awesome if one of us start a thread on this in the chemistry sub forum. I am really enjoying exploring all these calibration, analog converstion, testing different probes part :)
No problem, if one can choose 4 and 7 as the calibration points that works. The reason for the ph probe in my tank isnt to know that the ph is exactly 7.020 to the nth degree but accurate to .1 or .2 works. Id be looking at the trending as way more important, and i assume its the same in saltwater!
 

AquaRaider44

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Has the buzzing gone away now?
That fixed the majority of it but I still think something is wrong with the buck converters. Could it have anything to do with me using a 12v 4a power supply and its only rated for 2 amps? I don't think I'm drawing that much thought. Any other suggestions? Should I return these buck converters and get 4a ones or what would you recommend.
 
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