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

[AquaRaider44]

i'm just about to build the power module for my reef pi.
this is the first step for me so i wonder if you guys could help.
i keep seeing on youtube thees kind of video's showing a direct connection from the pi to the relay for example:

is there any reason why i shouldn't do this ? it seems really simple and less cluttered than the tutorial build on adafruit's website.

Also one last thing how do i tell if the relay module is good quality, i.e going to last me more than a couple of weeks ?

Hey I just went through the whole documentation for the build and this should work as it used a 5v relay and the circuit is designed for a 12v relay which needs all that extra stuff to step up and down from the pi to 12v relay.

 

[Ranjib]

Hey I just went through the whole documentation for the build and this should work as it used a 5v relay and the circuit is designed for a 12v relay which needs all that extra stuff to step up and down from the pi to 12v relay.

Yup , you won’t need the voltage converters if all your circuit is 5v.

 

[AquaRaider44]

Yup , you won’t need the voltage converters if all your circuit is 5v.

Correct me if I'm wrong but the voltage converter back powers the raspbery pi?

 

[Ranjib]

Correct me if I'm wrong but the voltage converter back powers the raspbery pi?

Yes

 

[AquaRaider44]

Yes

That is a nice feature and since the dosers and lights need like 12v and 10v it may be nice to step down twice and not have a few power supplies instead.

 

[AquaRaider44]

Thanks for everybody's help here. I have decided to go with building the whole Reef-Pi and all modules on one Ras Pi 3 b+ from scratch. I think I will enjoy this project and I see a lot of great help here if I need it! I should have all of the parts I need here on Wednesday #AmazonPrime1DayShipping. I waited on buying the pH module stuff I will end up going with the ph module from @Michael Lane as it cuts the price to $40 as to $80 having to buy the Electrically Isolated EZO™ Carrier Board and the Ezo™ pH Circuit. I will definitely go with this Milwaukee Instruments MA911B/2 Double Junction Ph Electrode with 2 m Cable and Gel Filled Electrolyte Solution as it is highly reviewed and is more actuate with the double junction. Just wish this pH module was supported already ;) but I will definitely wait as it seems like it could be in the next month. For pH calibration @Ranjib would 4.00pH, 6.86pH, and 9.18pH work?

 

[Ranjib]

That is a nice feature and since the dosers and lights need like 12v and 10v it may be nice to step down twice and not have a few power supplies instead.

Yes. and thats exactly how I arrived at 12v, because light , peristaltic pump etc all require 12 or 10v. I later realized that starting with higher voltage also means i can get more power with less current, which is handy. Breadboard, jumper wires etc has 1-2 A current limit, and if you start with 5v then you may need more than 3A.

 

[Ranjib]

Thanks for everybody's help here. I have decided to go with building the whole Reef-Pi and all modules on one Ras Pi 3 b+ from scratch. I think I will enjoy this project and I see a lot of great help here if I need it! I should have all of the parts I need here on Wednesday #AmazonPrime1DayShipping. I waited on buying the pH module stuff I will end up going with the ph module from @Michael Lane as it cuts the price to $40 as to $80 having to buy the Electrically Isolated EZO™ Carrier Board and the Ezo™ pH Circuit. I will definitely go with this Milwaukee Instruments MA911B/2 Double Junction Ph Electrode with 2 m Cable and Gel Filled Electrolyte Solution as it is highly reviewed and is more actuate with the double junction. Just wish this pH module was supported already ;) but I will definitely wait as it seems like it could be in the next month. For pH calibration @Ranjib would 4.00pH, 6.86pH, and 9.18pH work?

Go slow and start small, build the power, ato , temperature features first and then extend it to the other things. EZO IC only supports 4,7 and 10 pH value. The ph board and pico board which we are building will support only two point calibration, so two values will do, as long as they are with 7 to 10. I think 6.86 and 9.18 will work, but lets cross check.

 

[AquaRaider44]

Go slow and start small, build the power, ato , temperature features first and then extend it to the other things. EZO IC only supports 4,7 and 10 pH value. The ph board and pico board which we are building will support only two point calibration, so two values will do, as long as they are with 7 to 10. I think 6.86 and 9.18 will work, but lets cross check.

Ok it would be great if we could make these work as they are super cheap and easy to buy. 2 point should be fine as we won't be going that low lol.

 

[AquaRaider44]

Can anyone suggest me a float sensor they have used from Amazon? Looking for maybe like 3 of them.

 

[Ranjib]

Updates on the ph driver .
After sorting out the i/o error issue , last night I noticed the readings are not changing over time, it’s always a fixed value,. I went through @Roberto_b ’s program and noticed we have a missing driver logic where the board is set for continuous reading. I updated the driver code and after past 6 hours of running I am noticing the values being updated .

Next I’ll continue working on the calibration integration . I have also ordered another Milawukee probe to cross check the reading .

 

[AquaRaider44]

@Ranjib is that the same pH driver which will be used for Michael's pH board? Or will that be different than the pico?

 

[Ranjib]

@Ranjib is that the same pH driver which will be used for Michael's pH board? Or will that be different than the pico?

Yes this is the reef-pi open source/ openhardware ph board that’s designed by @Roberto_b from Italy , and reproduced by @Michael Lane . It is a simpler, no firmware board that can be configured for both ph or orp .
The pico base board has a full blown micro controller (among several other components) that can emulate this , which is why we hope the driver will work as it is for pico boards as well, but we’ll see . This is also opensource and openhardware board from @theatrus from California :-) .

 

[AquaRaider44]

Yes this is the reef-pi open source/ openhardware ph board that’s designed by @Roberto_b from Italy , and reproduced by @Michael Lane . It is a simpler, no firmware board that can be configured for both ph or orp .
The pico base board has a full blown micro controller (among several other components) that can emulate this , which is why we hope the driver will work as it is for pico boards as well, but we’ll see . This is also opensource and openhardware board from @theatrus from California :) .

Sweet thanks I'll definitely buy Michael's

 

[ChrisNH]

Yes. and thats exactly how I arrived at 12v

Modifying the Adafruit tutorial to work with the Elegoo power relay and using a 12v supply, I would keep the LM2596 but dump the ULN2803 (for this) and instead tie the relay board directly to the 8 appropriate pins on the hat?

Perhaps still going through a DB9 (or some other cable) and having the relay board and outlets located in their own enclosure.

 

[AquaRaider44]

Modifying the Adafruit tutorial to work with the Elegoo power relay and using a 12v supply, I would keep the LM2596 but dump the ULN2803 (for this) and instead tie the relay board directly to the 8 appropriate pins on the hat?

Perhaps still going through a DB9 (or some other cable) and having the relay board and outlets located in their own enclosure.

That's what I gathered from it. Using a db9 cable just adds to the cost why not build the power plugs in the same box with the relay and pi and just hard wire them using jumpers which u could remove if needed.

 

[AquaRaider44]

I got the power module parts for the jumpers, pi hat, and power plugs for 20$ instead of 70$ the other way. I will make a build thread tomorrow hopefully.

 

[AquaRaider44]

I'm still looking for float switches and was wondering if they are all the same and all need resistors

 

[ChrisNH]

I would prefer not to run 120 AC into the housing I am working with, I can black box the outlets and have them mounted up out of the way. I was considering 2x 4 channel rather than one eight. Just a personal preference.

 

[Ranjib]

Modifying the Adafruit tutorial to work with the Elegoo power relay and using a 12v supply, I would keep the LM2596 but dump the ULN2803 (for this) and instead tie the relay board directly to the 8 appropriate pins on the hat?

Perhaps still going through a DB9 (or some other cable) and having the relay board and outlets located in their own enclosure.

If the whole thing is 5V powered why you need the lm2596 IC? SainSmart documentation refers to use transistor in-between microcontroller I/O pin and relay board, and uln2803 serves exactly the same purpose, to have independent power draw and safeguard nothing draws too much power from pi gpio (should be les than 20 ma for each gpio and less than 500-700ma overall). I see more reasons to have the uln2803 in this case, am I missing something?