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

[Ryan115]

I have already started a thread on NR, under nano-box in sponsor forum.
You should be able to control as many as 18 channels with reef-pi, 16 from pca9685 and 2 from Pi

Would reef-pi support multiple pca9685s?
With the addressable pins, we can daisy-chain 16 units.
994 individual channels (992 + 2 on Pi)!!!

Not sure when this would come in to play, but it would be an awesome lighting/dosing setup!

 

[AlgaeBarn]

generally, solid state relays have lower current ratings (2-5 amp), while electro mechanical ones have higher current rating (10-20 amp). solid state relays are quite, while electro mechanical relays have that clicky sound. Some folks have said solid state relays last longer (due to no mechanical parts involved), but i have not tested so much that i can validate this.
The ADJ SR2 powerstrip that i am recommending going forward (in US) , uses electromechanical relays.

Hey Ranjib,

This if the first time I'm seeing the reefPi! Great idea! I was actually looking into making controller that we would use in house based upon a raspberry pi or similar windows based single chip computer.

Have you checked out the American DJ SR P8? You have 8 individual relays with some sort of serial connector packed up really nice. I was tempted to use a USB to serial module cable, and start trying to send signals to fire the relays, but with so much to do, I haven't been able to break away.

Not sure if you have answered this, but are you an electrical engineer?

 

[sjeff35]

Hey Ranjib,

This if the first time I'm seeing the reefPi! Great idea! I was actually looking into making controller that we would use in house based upon a raspberry pi or similar windows based single chip computer.

Have you checked out the American DJ SR P8? You have 8 individual relays with some sort of serial connector packed up really nice. I was tempted to use a USB to serial module cable, and start trying to send signals to fire the relays, but with so much to do, I haven't been able to break away.

Not sure if you have answered this, but are you an electrical engineer?

He's not an Electrical engineer, but he did spend last night in a Holiday Inn express ...

 

[AlgaeBarn]

generally, solid state relays have lower current ratings (2-5 amp), while electro mechanical ones have higher current rating (10-20 amp). solid state relays are quite, while electro mechanical relays have that clicky sound. Some folks have said solid state relays last longer (due to no mechanical parts involved), but i have not tested so much that i can validate this.
The ADJ SR2 powerstrip that i am recommending going forward (in US) , uses electromechanical relays.

If memory serves me correct, most electromechanical relays state about 100,000 cycles on their datasheet. Some higher end ones go into >1,000,000 cycles. Electromechanical can also do DC voltage (not sure the benefit of controlling DC voltage using a relay in this hobby). I worked on a project where our electromechanical relays went into the millions, but they were pricey and when we rebuilt the testing equipment, we made the jump to solid state relays.

Solid state relays can do well into the 40A range, and much higher, but those guys are huge (~2in x ~3in) and if you are powering that much amperage, you need a big heatsink for them. Not so hobby friendly. The cheap, non brand name ones tend to be dishonest with their amp ratings. The cheap ones started blowing up.

If any device would gain the most from a solid state relay, it would likely be the heater. Less likelihood of a cheap electromechanical failing ON ( if the heater does not have its own internal temperature control). This would be a super rare occurrence, and the increased form factor from a solidstate + heatsink may not be worth the tradeoff.

 

[Ranjib]

Would reef-pi support multiple pca9685s?
With the addressable pins, we can daisy-chain 16 units.
994 individual channels (992 + 2 on Pi)!!!

Not sure when this would come in to play, but it would be an awesome lighting/dosing setup!

Not currently, since I have never seen it being used fully yet. But I don’t think this will be an issue , it will very little effort to add support for multiple pca9685.if you are building something that will use this, let me know I’ll make sure the software is there ...

 

[Ranjib]

Hey Ranjib,

This if the first time I'm seeing the reefPi! Great idea! I was actually looking into making controller that we would use in house based upon a raspberry pi or similar windows based single chip computer.

Have you checked out the American DJ SR P8? You have 8 individual relays with some sort of serial connector packed up really nice. I was tempted to use a USB to serial module cable, and start trying to send signals to fire the relays, but with so much to do, I haven't been able to break away.

Not sure if you have answered this, but are you an electrical engineer?

Yes, infact recently I have started using those (ADJ SR P8, with db9 connector),. They work awesome, you can easily control two of those power strips with each reef-pi.
I am a software engineer by profession.

 

[Ranjib]

If memory serves me correct, most electromechanical relays state about 100,000 cycles on their datasheet. Some higher end ones go into >1,000,000 cycles. Electromechanical can also do DC voltage (not sure the benefit of controlling DC voltage using a relay in this hobby). I worked on a project where our electromechanical relays went into the millions, but they were pricey and when we rebuilt the testing equipment, we made the jump to solid state relays.

Solid state relays can do well into the 40A range, and much higher, but those guys are huge (~2in x ~3in) and if you are powering that much amperage, you need a big heatsink for them. Not so hobby friendly. The cheap, non brand name ones tend to be dishonest with their amp ratings. The cheap ones started blowing up.

If any device would gain the most from a solid state relay, it would likely be the heater. Less likelihood of a cheap electromechanical failing ON ( if the heater does not have its own internal temperature control). This would be a super rare occurrence, and the increased form factor from a solidstate + heatsink may not be worth the tradeoff.

I have no clue how things will work above 20A load. I would assume we have to rethink most electrical wiring at that level. I tend to restrict our designs to the controller and peripheral electronics, which are mostly DC, under 24 V, and 3 A. We have a few electrical engineering experts here in r2r, I tend to reach out to them for anything thats beyond my understanding

 

[AlgaeBarn]

Yes, infact recently I have started using those (ADJ SR P8, with db9 connector),. They work awesome, you can easily control two of those power strips with each reef-pi.
I am a software engineer by profession.

OMG! SOLD. I'll take 10 units!

Are you just using a usb to serial cable? Are the libraries live? Do you have a setup guide for the ADJ SR P8 or was the integration pretty straightforward?

 

[Ranjib]

OMG! SOLD. I'll take 10 units!

Are you just using a usb to serial cable? Are the libraries live? Do you have a setup guide for the ADJ SR P8 or was the integration pretty straightforward?

Nah.. nothing fancy, its db9, so 9 pin, each controls one channel, and a common +v. Let me dig up the pics.. I'll share again, I am pretty sure I have already shared them, but no harm in re-sharing

 

[MaccaPopEye]

So the HAT is ready to order PCB's for testing

It requires 12V input (and 5V to the PI) and offers an interface to max 16 external relais, 2 dosing pumps, I2C interface, 2 ATO's and interface to DS18B20 temperature sensors and fits directly on the PI ;Happy. So the whole device is the size of the PI, only slighty higher.

Due to its compactness I'm thinking of making a different PWM board which could fit on top as well. Have to think how to add more (I2C) boards on top such as the BNC interfaces.

Actual size:

Wykat this is awesome! Amazing job mate, I'm very keen to see how the HAT and PWM board fit together with the Pi

When you say 2 ATO's does that mean you can only use a maximum of 2 optical sensors or flat switches? If I wasn't going to use the dosing function (from the Pi at least) would I be able to use those GPIO pins for more optical sensors / float switches?

I can't remember if you replied before or not but would it be easy enough for me to get one of these shipped to Australia?

How the relays are connected to the board ? i.e. whats the connector type? It might be worth mounting the connector directly or think of how it upfront. I would love to see us settling on ADJ SR 2 power bars, which uses 12v , db9 connectors.

Ranjib I really like the look of the ADJ power bars it's a shame they can't be used by anyone outside of the US

I think it is better to leave the connectors off of the HAT and let the user wire up whatever connectors they want to use on the I/O side of the housing. While it takes a bit more work for the user to wire it up I think this makes the HAT way more versatile than having connectors directly on the board.

 

[wykat]

what program are you using , Please share...

I've used Kicad 4, just upgraded to version 5 this morning and FreeCAD to make some housings. Had to make some footprints (Kicad) and 3D models (FreeCAD) my self as well. Can share the .sch and .pcb or the files to order PCB's if you want, but note it has not yet been tested. I don't have a clear picture which footprints and 3D models or other files will be missing, but if you discover them I can share those as well.
The biggest problem I'm presently having is creating the BOM due to spaces in the directory and filenames. I think with the BOM I may get more information. Creating a BOM is a little tricky with Kicad, have to look into that. For the rest I'm very pleased with Kicad and there is very good support on the Inet

 

[wykat]

Would reef-pi support multiple pca9685s?
With the addressable pins, we can daisy-chain 16 units.
994 individual channels (992 + 2 on Pi)!!!

Not sure when this would come in to play, but it would be an awesome lighting/dosing setup!

On my I2C PWM module design you can set all 6 (a5-a0) addresses.

 

[wykat]

Wykat this is awesome! Amazing job mate, I'm very keen to see how the HAT and PWM board fit together with the Pi

When you say 2 ATO's does that mean you can only use a maximum of 2 optical sensors or flat switches? If I wasn't going to use the dosing function (from the Pi at least) would I be able to use those GPIO pins for more optical sensors / float switches?

I can't remember if you replied before or not but would it be easy enough for me to get one of these shipped to Australia?

As soon as I receive all components I'll will share pictures

The 2 ATO interfaces are intended for optical switches. For the ATO's you don't need an additional interface board as the components are already on the HAT as Ranjib correctly saw. The dosing connectors provide 12V which is too high for an external FSS-IR02 interface.

Let me first test the present HAT and then I can think of a different version as it will be simpler to move the dosing function to an I2C board (similar to PWM). If I recall correctly, Ranjib stated that his dosing function was going only in one direction, then I think it could be very simple. (presently I'm using 5 GPIO ports which I think can be reduced). I had a separate discussion with Ranjib on this related to the number of available GPIO ports.

I think I did reply for shipment to Australia that I think it would be simpler if you order the PCB's yourself (10 pcs for $2 plus shipment). Otherwise I can ship.

With respect to J9 (relais connector), I've planned Socket_Strip_Angled_2x10_Pitch2.54mm

Alternatively you can of course solder wires to the board and connect a DB9 in the housing.



Below the whole schematic

 

[Des Westcott]

If memory serves me correct, most electromechanical relays state about 100,000 cycles on their datasheet. Some higher end ones go into >1,000,000 cycles. Electromechanical can also do DC voltage (not sure the benefit of controlling DC voltage using a relay in this hobby). I worked on a project where our electromechanical relays went into the millions, but they were pricey and when we rebuilt the testing equipment, we made the jump to solid state relays.

Solid state relays can do well into the 40A range, and much higher, but those guys are huge (~2in x ~3in) and if you are powering that much amperage, you need a big heatsink for them. Not so hobby friendly. The cheap, non brand name ones tend to be dishonest with their amp ratings. The cheap ones started blowing up.

If any device would gain the most from a solid state relay, it would likely be the heater. Less likelihood of a cheap electromechanical failing ON ( if the heater does not have its own internal temperature control). This would be a super rare occurrence, and the increased form factor from a solidstate + heatsink may not be worth the tradeoff.

Interesting test on relays.


Funny guy too.

 

[Erica-Renee]

Interesting test on relays.


Funny guy too.

Interesting.. The relays were not meant to switch every second like that. Had he set it to even 3 seconds per cycle I bet it would have lasted much longer. The excess heat is the most likely cause of failure.. But of course the mechanical part failed. This can happen to any Mechanical relay at any time from its first switch to millions...

This does prove they are super Reliable

 

[Brad Cox]

I know this is off the wall.

Can i run pihole on the same raspberry pi as reef-pi?

 

[Ranjib]

^Ranjib, that would be awesome! Dave has been very helpful to me so far, which is a big reason why I hope to choose his DIY array. I am a member of NR, and would be grateful to tag along there too. You are always so helpful, thank you again!

-FF

Dave responded saying it will work just fine

 

[Ranjib]

I know this is off the wall.

Can i run pihole on the same raspberry pi as reef-pi?

It should, you may have to update reef-pi config to bind to an other port , if port 80 is used by pi hole

 

[Des Westcott]

Interesting.. The relays were not meant to switch every second like that. Had he set it to even 3 seconds per cycle I bet it would have lasted much longer. The excess heat is the most likely cause of failure.. But of course the mechanical part failed. This can happen to any Mechanical relay at any time from its first switch to millions...

This does prove they are super Reliable

Agreed. But it does show that the cheapest stuff out there can not necessarily be all that bad. Even the best quality stuff can go bad at any stage, but at least then you have backup and support.

He readily admits that his sample size of 1 is flawed and he does abuse it. But it shows that if you are lucky, they can work for a long time and you shouldn't just dismiss them because of the fact that they are cheap.

 

[Des Westcott]

Ranjib

I'm have ing a strange thing happen again.

Under equipment, suddenly i had the connector description disappear.


I tried to delete the equipment, and got this error in the pink bar.

And when i go to connectors and try delete there, i get the same thing.

This is similar to the problem i had previously.