DIY Automated Controls - Advice Solicited

piku

0
LifeTime Supporter
Mar 12, 2008
259
Hatfield, PA
Hello guys,

My equipment is pretty old and the paragon timer I have has no trippers. The intermatic trippers are incompatible not to mention I read that the mechanical timers are pretty wasteful. I am planning to do a control system for it. This is my thought thus far.

Nema 4 enclsoure
Linksys NSLU2 with custom linux system on it
3 contactors - 1 for pump, 1 for light, 1 for future peristalic pump (these would live in the current electrical box in place of the timer)
USB relay board (either DIY or buy one of the stupidly expensive ones already made)
USB io board (thinking the fusion board - typically used in automotive, but I already have another one)
2 temperature senders ( 1 tapped into the pvc for pool temp, the other dangling for air temp )
2 pressure senders ( 0-150 psi dakota digital )

The general idea is that with this kit I would be able to start up and shut down the pool pump/light based on any schedule. I would be able to then add controls into my home control panel so that I can turn on/off pool equipment from the living room touch panel. I would be able to write a small monitoring program that would make sure suction and pressure side numbers seem right and if not shut the system down and send me a text message. This would prevent the pump from running dry for very long because when it does the pressure side pressure goes to nothing. Suciton side vacuum would also go to nothing. I was originally going to interface with jandy valve actuators but they are expensive and now that I've solved my system leaks I don't have to manipulate the valves to successfully start the system.

Alternatives may be had for the NSLU2 - I could probably use a USB extender and just bury a CAT5 cable and conduit into my server in the house.

Additionally the pressure sender is for the car. Any industrial pressure sensors seem to be on the costly side ($100+) and this automotive air pressure sender is only $20 or so. I was thinking I'd just attach a long 1/4 or 1/8 tube between the sender and the pvc and probably water would never get to the sender. They also sell an oil pressure sender. I'd think oil gases are pretty bad so maybe it can handle the chlorinated water.

The temperature senders are for automotive coolant/oil. I've found that they are metal and they don't really indicate what kind of metal they are made from. I wouldn't want it to corrode and add metals to the pool water. They look almost like a really high grade bolt.

I have two main goals with this setup - inexpensive and reliable. The inexpensive part is important. I can't be spending $200 each for a pressure sensor. I need cheap <$20 sensors. Cost target of $300 is what I am looking for. The software is no problem for me at all - my main questions are what would you guys in the know do for sensors and relay/io boards.
 
You can just buy or make the temp sensor like the Fusion uses, then buy a PVC "T" that has a 1" threaded port. Get a PVC plug for the threaded port, and drill a hole all the way through the length big enough to slip the sensor in. Put the sensor right at the inside end of the hole and fill the hole with epoxy from both ends. Cheap enough you can keep some spares on hand.

Pressure sensors are harder, and the automotive ones may be the best bet. Water pressure sensors are commonly used in boat motors so that might be a source for one that wouldn't have to be protected from the water. Pressure sensors would be good because they could catch things like failure to prime or having a valve set the wrong way and shut down the pump.

I'm considering a similar system with a few different features:

1. Solar heat in,out and panel temperature
2. (I wish) water flow, but the cost is probably not worth it.
3. A water sensor on the floor of the pump room to detect a plumbing failure. (Pressure sensors might eliminate this need)
4. Motion detector/timer for area lighting, landscape lighting around water feature near pool area, and circulation control for the waterfall.
5. Irrigation system control for pool area landscaping.

This topic should probably be in "The Deep End", and I'll move it there after you have been here to see this note.

John
 
piku,

Nice little project you have started.

One inexpensive way to get tempeature sensors is to make or repair some broken GoldLine/Jandy temperature sensors:
http://www.mycal.net/?cpath=/Projects/p ... 7&action=9

Pressure sensors would be nice, but my GoldLine/Hayward AquaLogic control system does not use any. AquaLogic does use flow switches for some function, however.

The relays used in the GoldLine and Jandy automation systems for switching the 240 Volt and 120 Volt motor and lighting loads are Omron G7L-2A-BUBJ-CB-DC24 (contact form SPST, NO; 24VDC coil voltage, contact rating: 25 Amp @ 220 Volts)
http://www.mouser.com/Search/ProductDet ... 0r9w%3d%3d

The cost for these from Mouser Electronics is less than $16 each, not including shipping, which is quite a bit less expensive than the $50 or $60 commonly quoted for these relays if you get them with the Jandy or GoldLine brand. The only "catch" is that Jandy and GoldLine's wiring harness that they include with their relay uses a non-standard connector on the printed circuit board end as some sort of "pool standard" - but since you are not using any Jandy or GoldLine circuit boards this should not be a problem for you.

I have looked at Entertron Industries for an inexpensive PLC solution for pool control, but did not get very far in my research. The relay outputs looked really easy to do, but getting the proper combination of temperature input and outputs for motorized valves looked a little harder. And the hardest part was trying to figure out how to output a fairly high DC "signal" (5 or 10 or 15 Amps DC at the right voltage) in order to power the saltwater generator.
http://www.entertron.com/smartrelay.htm

It turned out the hardest thing, at least for me, was to find a water-proof wireless remote. My research let me to believe that by the time that someone had figured out how to build a reliable waterproof wireless remote, that they then went all of the way to build a complete pool automation system.

Here is a 12 channel RF wireless receiver/transmitter system that I purchased for less then $30. The remote is not waterproof, but for the cost one could always put the remote in a ziplock sandwich bag. The idea with this system was to use the relays as inputs to a PLC.
http://cgi.ebay.com/12-CH-RF-Wireless-R ... dZViewItem


Good luck on your project!

Titanium
 
Hi all,

I looked at the PLC controllers and decided they are too expensive. I have no experience doing any kind of hardware/microcontroller interfacing though I've read enough about it that I know how it's done. I've done a lot of research over the last couple of days and I think I decided on my kit.

That 12 channel RF relay board is really cool :) I can think of a number of ideas for that.

Appropriately sized enclosure from home depot
Linksys NSLU2 - will probably be able to handle pretty harsh temps
USB wifi adapter (forget digging and running conduit needlessly. Asus WL-330 reputed to work perfectly with NSLU2)
Arduino Decimilla - USB io. Only $34.95 at sparkfun :)
24VAC power supply to supply power to contactors
decimilla outputs connect to 3 transistors which connect to 3 relays which connect 3 contactors for output control
I've decided on 3 pressure sensors, 1 pre pump, 1 post pump and 1 post filter to monitor for output side blockages. It's overkill but isn't this whole thing? I mean this is to replace a dead timer after all :p
The pressure sensor I decided on is the freescale MPX2200DP. Pressure sensors have a HUGE range in price and at $11.25 each I am going to buy a spare or two in case I have failures. Though the suggested use of this pressure sensor suggests that it will work (automotive, industrial controls, etc). I just have to make sure water doesn't actually touch it through the use of decent length hoses. It's rated to around 30 psi I believe. I'm going to have it shut everything down above 20 so hopefully it'll never hit 30. Might be fun to test :p
I need some kind of rigid hose for vacuum on the suction side - will probably source something automotive.
For temperature I've decided on the LM34 temperature sensor. I will make a probe out of a small length of stainless brake line, insert the sensor in the brake line and use JB weld to seal it. It'll last forever.

That's pretty much my hardware spec. Now the whys. I could have used a nice PLC industrial controller and associated accessories but it would have gotten expensive quickly. I care about reliability but if reliability costs 10x the amount of cheap, might as well do cheap and buy spares you know? The above hardware can be sourced for less than $100 I believe.
I could have used a wireless USB extender and just housed the arduino outside but I just realized tonight that my compaq dl360 server has no USB. Additionally I'd rather it be able to run independently. I could program the arduino but I like linux and that's where I'd rather have most of the code live. The NSLU2 is a small $40 expense and worth it IMHO.
I might be able to go way way better with the pressure and temperature sensors but I feel I did rather well with the LM34 which I think is better than a basic uncalibrated thermistor. Conversely the pressure sensor I went way cheap on and am not sure how well it will hold up. I'll be buying differential sensors so they can function as pressure or vacuum. Not sure the purpose of buying a "gage" sensor.
I would have loved to have done this with PC hardware but it would have been expensive and unreliable. If I want a small linux/shell script control of my pool a small ARM based system is the way to go. And since my sharp zaurus is not going to live at the pool I needed something ultra cheap . I don't think it gets cheaper than the NSLU2 which has the magic requirements - network and usb host :)

It's unfortunate that no one place sells everything I need for this project. I am going to get raped on the shipping.

Comments/suggestions? I have a feeling I'm pioneering here a bit in terms of the open hardware for pool control.
 
piku,

I'm going to enjoy following your project. I have to admit that I am weak on the computer and networking and Linux side of things. PLC's and power is more my thing.

You realize, of course, that we are going to need pictures. Lots and lots of pictures.

Titanium
 
Hi guys, I'm new to the forum and this topic is very interesting to me.
Where can I get more info about DIY pool automation?
I've looked at all the packaged systems and doesn't look like any of them allows the flexibility that I need, being proficient in Linux and seeing this thread, has given me new hope!

Thanks, Luis.
 
LO19 said:
Hi guys, I'm new to the forum and this topic is very interesting to me.
Where can I get more info about DIY pool automation?

Welcome to the forum Luis! This thread seems to be the center of discussion for the idea, so I'd say your thoughts and questions are welcome here. I've put much thought into it for a couple of years. It's pretty similar to what I do at work, just more fun.
 

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Thank you John, same for me, I'm a Java Enterprise programmer by trade and I like to tinker with electronics, so this is right up my alley.

Thanks to you also, Jason, for your awesome calculator (although the mouseover feature doesn't work on my mobile's browser hint, hint) :) together with Google's calculator it saves me a trip to the inside when I'm adding acid or bleach.

Being new to pool ownership, I found this forum just a month ago and it was a blessing, within a few days I had all my chemistry down to the ppb (j/k).

I shall read more on that automation site.

Thanks again, Luis.
 
Hello all,

Finished my research and placed all of my orders:

$57.99 Linksys NSLU2 linux USB computer - eBay
$15.24 24 VAC Power Transformer - eBay
$26.74 3 Contactors - eBay
$35.00 Plastic Nema 3 enclosure - Lowes
$35.00 Arduino Decimilla - Adafruit.com
$12.00 Arduino Protoshield - Adafruit.com

And the following is my order from Mouser $46.00
2 LM34 Temperature sensor will use locally sourced stainless brakeline and JBweld to make a probe
2 MPX2200DP Freescale MPX pressure transducers
1 MCP120-45DI/TO-92 type D bondout - makes Linksys NSLU2 auto power on after power failure
3 VE-5HSE-K Fujitsu 5V relays
3 TIP102 NPN transistors

Just under $200 total. If I added Jandy valve actuators that would really cause some expense.

I've not yet decided if I will trench a cat5 run to the pool equipment or use a USB wlan adapter. Most likely I'll just run CAT5. But I have what I need to get started on the most important part to me. Control of the motor via a network connected box. Progress and pics to follow once I start receiving things.
 
It's this guy http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=150219242920&ssPageName=STRK:MEWA:IT&ih=005. It's very generic 20 amp DPST. I figure since my 1HP 1.1 SF Hayward pump draws something like 7.5 amps it shoud be fine. (2x surge means 15 amps fits within 20 amps). I find it interesting though that the circuit coming out to the pool is 40 amp. I wonder how much more stuff I could squeeze on there. Heat pump? :p

Btw, his pic server is down so google for the pic of the contactor. It looks fairly basic. I didn't even consider reliability since I know nothing about electrical brands. (Other than that Leviton is held in high regard).
 
Great thread.

I've been thinking/researching this for a few months now, I just have one small thing preventing me from moving forward, that is how is the system going to interface with my wife. I'm not quite sure how to do this either from within the house or by the pool.

My plan was to control the pool pumps, slide pump, pool light and pool deck lighting all from the controller.

I had my eye on this guy: http://www.apogeekits.com/usb_interface.htm

Of course Velleman does not release/support a library for Linux, but there are a few available.

looking at the Omron G7L DPST 24v relays for the pumps and SPST for the lights. I was originally going to run it from one of the 4 linux boxes running in the basement, but I like the idea of the Linksys.

Still what eludes me is how to control it when not in front of a computer. I though about using a remote for a Dolphin spa, using an IR receiver (LIRC) to map the pump/light buttons for my needs, but I'm unsure if those buttons are relayed across the wireless receiver and some of the reviews say the wireless range sucks. So, I'm still looking.

I'm interested in hearing of your successes.
 
crabboy,

Are you SURE you really want to use your computer as the main controller for your pool. I'm a big fan of some kind of control electronics dedicated to the pool. It would really bite if a computer crash caused you to lose control of your pool (unless you left in some sort of manual control for the pool pumps and valves, etc.).

Still what eludes me is how to control it when not in front of a computer.

Being able to adjust the heater, and the turn on and off jets, and control the pool/spa suction/return valves WHILE IN THE SPA let me to automate my pool in the first place. Nothing quite takes the edge off of the margarita buzz than having to get up out of the hot spa and tromp over, in the cold air, to the equipment pad to adjust the valves or the heater. Not too mention the danger of messing with electrical or plumbing while a) wet, b) in the dark, and c) half-drunk.

My interface of choice is a floating, water-proof, remote control that I can use while I am in the spa. Unfortunately, finding a floating, water-proof remote control has proved elusive. It seems that everyone who has a water-proof remote control has also made a pool automation system already. Hence I ended up going with the GoldLine/Hayward AquaLogic control system. http://www.h2opoolproducts.com/product_ ... cts_id=631

The only problem that I have with the AquaLogic is that if I want to do something a little different than the canned program on the AquaLogic, then I am out of luck. My dream is to be able to spec/design a PLC-based pool control system that anyone would be able to build from scratch. The biggest sticking point, however, is that darn water-proof remote control. I can find lots of remote controls - just not waterproof ones.

What really ticks me off about everyone's pool automation system - Hayward, Pentair, Intermatic, etc. - is that the cost differentials between their 4 output vs 8 output vs 16 output is outrageous. The difference in actual hardware costs between the 4 vs 8 vs 16 is really minimal, yet these guys want another $1000 (or more) to jump from the 4 output to the 16 output versions.

Titanium
 
Worried about bugs in my code, eh? Yea, I've got a backup plan. Leave the archaic 70s style Intermatic timers on the wall outside and just remove the on/off toggles. When I'm done, and if I had a crash, I'd be no worse off than I am now, with my dial timers and having walk to the side of the house, unlock the gate to turn either the slide, light or filter pumps on.
 

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