Troutt's Reef-Pi Build

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Jonathan Troutt

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Hey guys I got a bit of a problem I am trying to figure out here. I ordered another PCA9685 because I thought the original one I got I ruined. Well the new one isn’t being recognized by my raspberry pi either.

I ended up corrupting the sd card of the pi so I had to reinstall the os on the raspberry pi. I used noobs to do it as I did the first time. I have enable i2c in raspi-config and added the # to raspi-blacklist.conf. Even though it was blank. I added the hashtag anyway.

This procedure worked before I corrupted the sd card. What am I doing wrong? Are the i2c lanes messed up on my pi? Not sure why they would be but exploring all options. Is there a way to check them without having an oscope?
 

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If you’re getting less than 3.3V, check the pull-up (10k) resistors on the SDA line. The line should idle high.

Also check the voltage level with nothing else connected except the Pi and the resistors.

Also make sure you haven’t tried to use the SDA pin as another function.

If your multi meter has a fast min/max mode it’s also useful to see if the voltages vary when you try to use it.
 
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If you’re getting less than 3.3V, check the pull-up (10k) resistors on the SDA line. The line should idle high.

Also check the voltage level with nothing else connected except the Pi and the resistors.

Also make sure you haven’t tried to use the SDA pin as another function.

If your multi meter has a fast min/max mode it’s also useful to see if the voltages vary when you try to use it.


SDA is sitting at 3.3v. The only multimeter I own is a Fluke 115. There is a very small fluctuation in voltage is I run i2cdetect command but we are talking 30-40 mV. I am trying to get this working on a fresh install of raspbian and reef-pi.
 

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SDA is sitting at 3.3v. The only multimeter I own is a Fluke 115. There is a very small fluctuation in voltage is I run i2cdetect command but we are talking 30-40 mV. I am trying to get this working on a fresh install of raspbian and reef-pi.


I wouldn't worry too much about the software, assuming your /boot/config is setup right and no other outlets in reef-pi override those GPIO pins. Seeing a little change on the meter is good, as it likely means the line does see activity meaning its not totally dead or misconfigured. The Fluke 115 has a Min/Max mode, I just don't know if its fast enough for this purpose. You can try using it and see what the min/max voltage is reports on the lines is when you run i2c detect.

Do you happen to have a picture of the wiring setup you're testing with? If its above sorry I missed it, feel free to link me to the post.
 
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@theatrus

I am at work currently. I am going to go and buy another raspberry pi 3 today. I want another one anyway and this will allow me to have a second unit for testing.

I will take pictures tonight and post them up.
 
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@theatrus

New raspberry pi solves my issue. Both PCA9685 modules are good. Some how I damaged the i2c bus on the first raspberry pi.....bummer.

At least I got it up and running.

@Diamond1
my lights work exactly like yours do. I was thinking about how to wire my lights to my reef-pi.

I have a abundance of ethernet cat5e cable laying around. I was thinking I could use it for this purpose. I feel like it would be perfect. 8 wires, 4 for each driver. Get a jack and mount it right to the back of my light and the same for my enclosure for my reef-pi.

My only question is the wires are a small gauge obviously I know I wouldn't have an issue with the PWM and GND. But would running 12v through a relay and back to on/off be a problem for cat5e?
 

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@theatrus

New raspberry pi solves my issue. Both PCA9685 modules are good. Some how I damaged the i2c bus on the first raspberry pi.....bummer.

At least I got it up and running.

@Diamond1
my lights work exactly like yours do. I was thinking about how to wire my lights to my reef-pi.

I have a abundance of ethernet cat5e cable laying around. I was thinking I could use it for this purpose. I feel like it would be perfect. 8 wires, 4 for each driver. Get a jack and mount it right to the back of my light and the same for my enclosure for my reef-pi.

My only question is the wires are a small gauge obviously I know I wouldn't have an issue with the PWM and GND. But would running 12v through a relay and back to on/off be a problem for cat5e?

How much current in amps are u planning on running thru? Cat 5 is usually only 22awg or 24 awg? For 22 awg I wouldnt recommend more than 3 amps. And for 24 awg, not more than 2amps.
 
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Jonathan Troutt

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  1. I would also like to know this?

    Ok so from what I have found out according to

    https://en.m.wikipedia.org/wiki/Category_5_cable

    Is that cat5 can handle 500mA. Which is perfectly fine for what I am doing with it.

    How much current in amps are u planning on running thru? Cat 5 is usually only 22awg or 24 awg?

    The cat5e that I have is 24awg. See above. It’s only going to carry 12v signal to turn drivers on and off and a 3.3v 200hz pwm signal for dimming control. I am currently working on wiring the jacks that are going to be in the reef pi enclosure.

    I made the mistake not to buy the tool to push the wires into the jack.....
 

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  1. Ok so from what I have found out according to

    https://en.m.wikipedia.org/wiki/Category_5_cable

    Is that cat5 can handle 500mA. Which is perfectly fine for what I am doing with it.



    The cat5e that I have is 24awg. See above. It’s only going to carry 12v signal to turn drivers on and off and a 3.3v 200hz pwm signal for dimming control. I am currently working on wiring the jacks that are going to be in the reef pi enclosure.

    I made the mistake not to buy the tool to push the wires into the jack.....
I edited my post...for just signal cat 5 is fine...22 awg MAX 3 amps, 24 awg, 2 amps...less if its a long run but for less than 1 amp signal..cat 5 should be good. Anything more than one amp and I personally would use 18awg or better, cat 5 is good for signal its what im planning on using myself for the pwm signals to my lights if I decide to put my homemade drivers inside my light housing. I may decide to do otherwise and my lights draw 4 amps on a channel, so 18 awg it is. A good source of inexpensive multiwire cable for 18 awg is thermostat wire, bearing in mind it is solid conductors, not stranded.
 
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I edited my post...for just signal cat 5 is fine...22 awg MAX 3 amps, 24 awg, 2 amps...less if its a long run but for less than 1 amp signal..cat 5 should be good. Anything more than one amp and I personally would use 18awg or better, cat 5 is good for signal its what im planning on using myself for the pwm signals to my lights if I decide to put my homemade drivers inside my light housing. I may decide to do otherwise and my lights draw 4 amps on a channel, so 18 awg it is. A good source of inexpensive multiwire cable for 18 awg is thermostat wire, bearing in mind it is solid conductors, not stranded.


Yes sir I found the same info. Not going to carry anything close to 1amp here gotta get a few more things to get it all up and running.

Ignore the sharpie marker under the db9. I am going to plastic weld these connectors in as I want the box to be watertight. I am debating using solid state relays to switch the 12v on off signal.

image.jpg
 

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I built a simple RC circuit to run my SB reeflights off of a Kessil controller which I assume is a PWM signal and I couldn't get that to work. One AA battery hotwired to an audio cable dims my lights though. In other words I'm not good at designing circuits and I'm not too sure I can build them either but I'll give it my best to keep from praying to the Apex!
 

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