Pool Automation Controller

[sequent]

If you are interested in a Raspberry Pi-based Pool Automation System, please share your thoughts here.
We will try to draw conclusions about the best set of specifications, and hope to bring it to life soon.
In short, please help us define the board level inputs, outputs and communication interfaces required to automate your pool.

 

[rickross]

It would be great to support multiple heating systems (solar, heat pump, gas heater, etc) for any given pool. I’d like to be able to set heater priorities, whether to run more than one type simultaneously, and how and when to do so.

Solar heat needs a well-considered set of trigger conditions, and it would also be great to be able to configure it for cooling as well as heating. Sometimes shedding heat at night with the solar racks is desirable.

 

[Katodude]

Dont know if you can fit the relays and everything else on one board.

8 Relays (to control pool equipment)
4-20ma inputs (for pressure transducer or reading pH)
0-10v inputs (for pressure transducer)
RS-485 (to communicate to the pool equipment)
Powered by 24VAC or 24vDC (Most pool controllers will have 24VAC to drive the valve actuators)
supplies power to Pi and other hats.
1 wire. (generally for a temperature sensor)
Something like a Whitebox Lab T3 card built in. (For ORP and pH sensors)

I am sure I am forgetting something but this is a great start.

 

[DGTLDAV]

Let me ask these questions about the goal of Sequent systems. Is the goal to make:
1. A circuit board or circuit boards that plug into a raspberry pie, and all of the software, packaging, wiring is done by the purchaser, as sort of a DIY, build your own pool controller project where the purchaser/user writes the software?
2. To make all of the hardware, packaging, etc. as far as the controller and this to be an open source project, including a software to make a professional level pool, controller, that anyone can build, call, modify, and tailor to their own needs?
3. To make a professional all inclusive, pool controller.

 

[DGTLDAV]

Let me ask these questions about the goal of Sequent systems. Is the goal to make:
1. A circuit board or circuit boards that plug into a raspberry pie, and all of the software, packaging, wiring is done by the purchaser, as sort of a DIY, build your own pool controller project where the purchaser/user writes the software?
2. To make all of the hardware, packaging, etc. as far as the controller and this to be an open source project, including a software to make a professional level pool, controller, that anyone can build, call, modify, and tailor to their own needs?
3. To make a professional all inclusive, pool controller.

I hit post accidentally.
3. To make an all inclusive pool controller similar to the likes of Jandy, Pentair maybe be in the pool controller business?
I have pretty much everything Jandy had to sell and it’s expensive and they no longer want to sell items like this over the Internet, so it gets even more expensive if you want to upgrade or service your unit.
Now might be the right time for something else to come on the market at suits the users needs, doesn’t cost an arm and a leg, it is more modern and has additional features lacking in some of the units that are out there?

 

[JLB]

For a pool automation controller I need several temperature sensors (I use One-wire for the moment)
For the Pool height I’m using a MaxSonar sensor readings by reading serial data.
For testing the water health there must be a sensor for Temperature, PH, ORP/Redox, Conductivity this is the minimum test equipment for clear water.

For measuring the waterflow I have a water flow sensor consists of a plastic valve body, a water rotor and a hall-effect sensor
A second serial is posible for reading a Arduino because the Arduino is more suitable for reading the hall-sensor waterflow.

A 3e serial is for reading the heat pomp UART 4D

This is the basic I think

 

[Katodude]

I believe the goal here is to make a board that is well suited to be used in building a DIY pool controller. You could program your own software, or use the NodeJSpoolController.

GitHub - tagyoureit/nodejs-poolController: An application to control pool equipment from various manufacturers.

An application to control pool equipment from various manufacturers. - GitHub - tagyoureit/nodejs-poolController: An application to control pool equipment from various manufacturers.

github.com

The current NodeJS supports the current Sequent relay cards as well as the MegaInd and the MegaBas. I currently use a MegaInd which just got blown by a lightening strike. So I have ordered a MegaBas to replace it, as well as a new Relay board. This will be my 3rd generation of a pool controller using the Sequent cards.

The ask seems to be what features are you looking for in a board that has all the features that would be used in a pool controller assembly.

Ultimately if the MegaBas had 4-20ma inputs it would be most of the way there. The addition of inputs for pH and ORP like the whiteboxlabs takes it just about all the way there.

 

[DonFL]

I hit post accidentally.
3. To make an all inclusive pool controller similar to the likes of Jandy, Pentair maybe be in the pool controller business?
I have pretty much everything Jandy had to sell and it’s expensive and they no longer want to sell items like this over the Internet, so it gets even more expensive if you want to upgrade or service your unit.
Now might be the right time for something else to come on the market at suits the users needs, doesn’t cost an arm and a leg, it is more modern and has additional features lacking in some of the units that are out there?

Your post raises the exact questions I had. Just what is the goal, and the envisioned offering? The hardware side is just one piece of it, but the software interface, be it roll your own or an open-source community effort, is just as important.

I have an older (circa 2003) Jandy controller, on it's last legs and way outdated, but it's still does the basics...on/off of pump, heater, valve control water features, valve control for spa vs pool, controls salt system. Has temp sensors, remote display and control (wireless 2.4 ghz ISM). The Jandy controller of today are much more sophisticated, of course, with phone app control, control of multi-speed pumps, etc etc.

I'm looking forward to seeing how this evolves, and no matter what the approach, it's pretty likely I'll be making a purchase.

 

[TriLife]

Some further thoughts on a PAS:

I built a chemistry monitoring system, based on an arduino Mega 256.

It monitors pH, EC, temperature and filter pressure. It also provides DC current via a pair of relays to a the copper ionization system I use in lieu of the typical chlorine based treatment systems. For the latter, you'd need an ORP sensor. Atlas Scientific has a nice array of sensors and HATS for Arduino and RPi for this purpose, along with little stamp sized signal conditioning modules.

Pool valves are still mostly 24Vac driven, 3-wire affairs, although they are starting to sell ($$$) PWM versions. A typical system would need a minimum of 2, but ideally 4 or 6 valve drivers.

There is a touch screen, which allows me to monitor what's going and calibrate the sensors.

A simple webserver allows me to remotely see the status

It also sends emails of Log Files and alarms

The sensors are I2C based.

In order to communicate with the Pentair Pump, it needs an RS485 interface.

If you go on the CocoonTech.com or troublefreepool.com forums, there are a bunch of discussions on how to communicate with Pentair pumps.

It would also be important to have a comms interface with home automation systems. I'm a developer (budding) with Universal Devices and can try to help you with developing a node-server for their Polisy and eISY systems.

Cheers

 

[travelbug]

If you are interested in a Raspberry Pi-based Pool Automation System, please share your thoughts here.
We will try to draw conclusions about the best set of specifications, and hope to bring it to life soon.
In short, please help us define the board level inputs, outputs and communication interfaces required to automate your pool.

Hi Guys,

As per your email, I know something about pools (my dad used to sell and install them, and was an electrician and plumber to boot).

I am an electrical engineer, that dabbles in home automation and digital control systems. My comments are as follows.

This might be a great idea, but you might want to target a slightly wider audience/customer base. Pools have a lot of similarities (but simpler), than aquariums!

There are a LOT more aquariums out there than pools, but the combination is a large market. Yes there are aquarium controllers out there already, but they are mostly closed, proprietary non expandable /non-customizable. You might kill two birds with one stone if you take this into your design considerations,

Some features of both pool and aquarium controllers:
monitoring:
Temperature monitoring (pools can use multiple temps if they have a solar heater loop.... If temp in loop is greater than temp in pool, turn on loop pump..etc
loop inlet/loop outlet/main temp/ outdoor (air) temp
PH monitoring (should be able to use off the shelf scientific / industrial pH sensors - calibration etc.
ORP monitoring
Sunlight? monitoring ( for day /night determination)

REAL TIME CLOCK

Control:
circulating pumps (2 at least?) main pump aux pump, solar loops?
heater on/off (timer, or setpoints (from temperature monitor, or logic driven)
pH doser control (can be dosing pump? or just relay to control) dosing motor (generally a peristaltic pump)
ORP control ( relay output, generally for OZONE generator).

Lighting control (pools - underwater lights, outdoor lights etc)
lighting controls /(aquarium: LED/HID, etc) timer based, generally 2 -3 outlets for staging (separate timers for moonlight.daylight etc. BONUS - dimming of LED lights for ramp up ramp down.

Aquarium only:
FEEDER output: feeder timer set for 1,2,3,4 times per day. Relay output. Logic also turns of certain circulation pumps.
Filter (sump) pump control (logic, and timer).
4x Circulation pumps (timer on/off, cyclical, logic triggers)
Protein skimmer pump control (relay on off, timer, logic driven)

Logic circuitry.
Simple logic for on off
Alarm conditions (overtemp, pH out of range, ORP out of range, no circulation


Display/notifications (from software)
Email, SMS, local display, phone app?
WiFi enabled? WiFi reprogrammable (OTA)


Hope this helps getting your creative juices flowing.

Best will be open design, expandable, customizable.

Let me know what you think...!

 

[sequent]

Our goal is to design a single card similar with Building Auto and Industrial Auto, with dedicated inputs and outputs to handle all the Pool Auto needs. So far I've learned the following:

CHEMICAL INPUTS
We need to read chemical values which need dedicated probes and boards. The most convenient way for everybody is to include on-board carriers for the Atlas Scientific modules like the EZO-pH Circuit. If you want to measure pH, you plug the module in. Else, leave it empty. I am inclined to include three carrier sockets. Atlas seems to have modules for all the stuff one might want to measure in the water.
We designed something similar for another customer.


TEMPERATURE MEASUREMENTS
The way to go seems to be 1-Wire. You can daisy chain multiple probes to read water and air temperatures. Probes are cheap and offer enough precision. I do not see the need for super-precise probes like RTD

ISOLATED RS485 INTERFACE

24VAC POWER SUPPLY

RELAY OUTPUTS.
The consensus seems to be lots of them. Probably 12 is a good number. Normal open only, 2A/24V.
Just in case, the card would be expandable, so you could add another 16-RELAYS on top.

HIGH POWER LOADS.
Not on this card. We have a 3-RELAYS card which can switch 40A/250V and can be chained on the RS485 interface.
Best would be to keep the high voltage elsewhere, next to whatever you use to heat or pump the water.
With this card you can control almost any 3-phase high power load, inductive or resistive.

OTHER ANALOG INPUTS AND OUTPUTS
Here I do not have clarity. Your input would be appreciated.
Do you need 0-10V or 4-20mA IN and OUT? How many of each?

 

[Katodude]

@sequent

Chemical Inputs:
Yes, this is exactly what we need. In fact I am in the market for one of these right now.

Relay Outputs:
12 is a good number, but you could probably get away with 8. Also we use the relays to control valve actuators that move in both directions so we need the relays to have NO/NC. (I would be interested to see what others say here)

Analog inputs and outputs:
For a pool in most cases we are measuring the status of something. I dont think we need any outputs (lets see what other say). I would think 4 0-10v inputs would be sufficient and 1 4-20ma input would also be good.

 

[sequent]

I would rather use Solid State outputs with MOSFETS to control the bidirectional valve actuators.
How many valve actuators would you like to control? What is the maximum voltage and current?

 

[travelbug]

The 0-10V (outputs) would allow dimming for the lighting systems. I'd like to see 2 minimum but 2in /2out would be great. 4-20mA? Maybe for future proofness or compatibility but I personally don't see a need, thats just me.

I really like your 3 probe (pH, ORP, Conductivity) that's perfect for pool or aquarium/hydroponic setup.

Can you consider 12VDC or at least make it compatible? for us here in US/CAN ,, 12VdC is much more common than 24vDC (like Europe /UK) , but I am sure you can make it compatible with both???

opto isolated MosFet Drivers for solenoids, valves or PWM???? I can get my LED dimming done this way!! ? I'd trade 6 relays for 6 MOSFETS. (6 of one, 6 of the other?) That would be the cats meow! I think the relays should be NO/NC contacts, for people trying to do polarity switching (i.e drive a linear motor one way with +/- and reverse it with -/+ ,,Needs to sets of contacts to accomplish.
this is for AUX equipment that can utilize a linear motor (opening windows/vents), rotating a solar panel etc...automatic pool covers/shades etc...

Assuming the Pi can do the stuff like SMS, ethernet/wifi notifications etc in the APP/software.

Last thing? RTC??? for timers, time of day, alarms etc. sequencing and timing logic...

You have a winner on your hands with the Marine aquarium guys...if the above can be met! Maybe the greenhouse hydroponics crowd as well...

Oh, I2C humidity and Temp /Barometric chips are super accurate and reasonable... Can you bring out I2C pins, and some code for SHT30 or BME 280 ??? These chips are less than $10 and give .1deg accuracy and resolution and 2% humidity (I know pool guys probably don't care about humidity unless they are indoor pools in which case exhaust fans would be triggered with high humidity setpoints.)

keep on keepin on!

 

[travelbug]

Oh and I second the comment making it compatible with home automation...such as SmartThings, Home Assistant and Hubitat in that order...

 

[negllic]

Hi,

I already built my own Pool controler based on raspberry PI.
.NET software with a responsive web page to control anything from a smartphone, a tablet or a PC.
Got also alerts by email.
But most interesting design I made is an nice algorithme (nowadays I should say "AI" ) that adjust every hour the filtration time depending of the actual temperature of the water (controlled with a simple DS18B20 sensor inside the pipe).



There are already a lot of ideas here, let me just add 3 points :

1. Device needs digital inputs to monitor the circuit breakers (circuit breakers have an NO/NC automation contact). Because if a circuit breaker blows up, your software in the raspberry will think driving the pump whereas nothing runs.
2. Be careful in relay choice. A simple relay won't be good to drive a pump as there are some overcurrent will stopping the pump. You need a contactor, which is a relay with special design to clean the contact at each start/stop. Solid state relay is a good choice also, be there are some thermal design to consider
3. You need a human machine interface inside the machinery room for driving the pumps : maintenance, filter backwash, etc.... For my system, I add a small HDMI touch screen 3.5''

Otherwise, 1wire for temperature, 0-10V for chemistry, etc... All the other ideas here are good.

 

[volkswagner]

Great stuff here. Let's consider the modular approach. For example, not everyone will want/need/afford the full
water chemistry automation. Perhaps the water chemistry can be on one hat by itself. Some pool owners simply want a way to control their pool heater remotely (think weekenders). Some electricians/pool companies may want a commercial-quality solution that promises to be vendor-neutral and use open protocols (uses "off-the-shelf" hardware), vs something that "looks DIY".

I see a lot of reference to "one wire" for thermals. I'm not sure what this is, but I think Pentair systems use two wire thermistors. I don't think we would want to exclude the ability to convert existing systems that have failed or don't meet pool owner's needs. I realize replacing the temp sensor may be a minor expense, so if one wire is superior, so be it.

 

[Katodude]

I would rather use Solid State outputs with MOSFETS to control the bidirectional valve actuators.
How many valve actuators would you like to control? What is the maximum voltage and current?

Pool valve actuators when running draw .75A at 24VAC

I personally have 4 valve actuators, but I know of others that have 7.

The pool pump is a large draw but has full time power to it (so no need to switch it on and off) and its speed is controlled by the RS-485
The SWG gets controlled by one relay and is 120v
The pool heater also has a fireman switch that it toggled by one relay.

So in my case I currently use 1 relay hat to control everything.

 

[tjd999]

Katodude's first two points were:
The pool pump is a large draw but has full time power to it (so no need to switch it on and off) and its speed is controlled by the RS-485
The SWG gets controlled by one relay and is 120v

On my DIY Pool Automation sytem, I implemented the following:

1. Pool Pump - correct - the RS485 controls my pump speed but what would I do if the pump needs to be worked on? The pump controls, RS485 and voltage power connections, are very close to each other and the pump maker insists you turn off power to pump when opening it up. My voltage to pump goes through a circuit breaker then to the relay and then to the pump. In Florida, the heat is brutal so I shut down power to all relays each night to alleviate this issue. I also monitor the temperature in my PA box to alleviate frying my RPI. If it occurs, I, send myself an email.

2. SWG - correct - one relay. Most SWG devices comes either 120 or 240 capable. 240 volts uses less current so it is cheaper to run.

I don't mean to be nitpicky but it just shows you the multiple wants/needs of DIYers.

 

[rstrouse]

I have built 6 diy pool controllers, all using Sequent cards as their backbone. Equipment control for items such as pumps, heaters, chlorinators, and some valves are all done via RS485 (not modbus). These protocols are unique to the manufacturer and often operate at different baud rates. For instance, all Pentair equipment operates at 9600 baud and Hayward operates at 19,200 for pumps and 9600 for AquaRite. There are a number of off-branded pump drives out there that have a modbus interface but if you look you will not see broad support for them. Jandy is another thing altogether and most of the projects out there have been abandoned.

Valve actuator control is 24vac (750mA) and requires a NO-COM-NC relay since one side of the valve must be powered at all times for proper operation. Typically no more that 3 valves are in transit at any given time. This also includes endstop valves actuators supplied by a number of manufacturers. The high power relays typically use 24vdc coils with flyback isolation. These can be NO-COM relays.

Temperature sensors that exist for easy installation in a pool setting (UV and chemical resistance) are 10k thermistors. There are tons of them out that already come with PVC jacketed wire that is potted into the sensor. They are around 20 bucks a pair and will last a lifetime. On the typical pool there are 3 that are used to identify heat demand (water temperature), solar capacity (solar temperature), and air temperature. When the pool is a dual equipment then there is a pair for water temperature of each body and the air and solar temperature are shared.

When it comes to chemistry control. You will need at least 2 isolated carriers and 1 non-isolated. The amplifiers in the Atlas pH and ORP circuits are sensitive to all that noise on the equipment pad and must be isolated. The third carrier is for an embedded temperature sensor that is used to calibrate the pH probe as output from that is temperature bound. With many of the probes for use in a non-laboratory environment the temperature sensor is located in the probe itself. In the Pool world dissolved oxygen is not that common. Not sure what that would get you in a wide open body of water anyway. TDS sensors can be useful only to the extent that they reflect the salt levels in the water when the proper factors are applied to fresh water.

The most common peristaltic pumps out there are either 120vac or 24vdc. So power considerations on the controller need to be take into account. A single 24vac power supply can be used if there is the ability to power the pi using 24vac like you can do with the BAS. This same power supply can then be used to power valves. If there is a desire to use 3hp relays (kinda required for 2-speed pumps) then a rectifier or a separate 24vdc psu can be used that also powers the peristaltic pumps.

While I have seen a number of folks out there switching RS485 pumps and heaters on a relay, that is flat wrong and should not be done. They should be powered at all times. The internal workings of the pump drive and the heater control board understand a call for heat and perform all the appropriate switching. Only single speed pumps should be switched in this manner and most states have outlawed them for pool use. If a heater is tied into a spa/pool scenario this should be switched on the filter relay.