My Raspberry Pi Pool Timer Project — Bill of Materials

(Previously I discussed the the why of this project, the parts I selected to build with, setting up the Raspberry Pi itself, the electronic assembly, the mechanical assembly in the backyard, and the Rasptimer software I wrote for it.)

Here’s the project bill of materials, not counting things like that I replaced or improved “while I was it”, but just the ones core to the project:

	Item and source	Approx. cost	Total
1	Raspberry Pi Model B (from Newark)	$35.00	$35.00
1	Wi-Pi USB adaptor (from Newark)	$16.48	$16.48
1	4 GB SD Card (from Fry’s)	$7.00	$7.00
2	Deltrol Relay 267F DPDT (from onlinecomponents.com)	$14.16	$28.32
1	Power supply 5V and 12V (from Sparkfun)	$9.95	$9.95
2	MOSFET 30N06 (from Sparkfun)	$0.95	$1.90
2	10K resistors (bought bag of 10 from Sparkfun)	$0.95	$0.95
2	1N4001 diode (from Sparkfun)	$0.15	$0.30
1	Prototyping board (from Sparkfun)	$2.95	$2.95
1	Aluminum enclosure (similar to this from Fry’s)	$20.69	$20.69
1	Plastic enclosure to keep Wi-Pi out of the metal box and protected from weather (similar to this from Fry’s)	$7.99	$7.99
1	Terminal wire connectors (from Lowe’s)	$2.06	$2.06
1	micro-USB chord (from Fry’s)	$1.99	$1.99
1	USB extension chord (from Fry’s)	$3.29	$3.29
1	Custom front panel for control box (from Advantage Metal Products)	$20.00	$20.00
Various little odds and ends, like a few feet of 16-gage stranded wire, soldering material, screws, bolts, nuts			$5.00
Total:			$163.87

Not a bad price. I note that Leslie’s sells mechanical timers for pump control at $77.99 each. If I had used those, I also would have had to pay for the custom faceplate, and the total would have been $175.98, which is slightly more. But with none of the goals that I set out for the project, like remote control, or adaptive scheduling.

Now all that’s left to do is to create a video showing the system in action…

6 Responses to "My Raspberry Pi Pool Timer Project — Bill of Materials"

danielq says:

September 5, 2013 at 02:30

Hi jernst,

compliment for this great job.

I’m creating not a pool timer but a cronothermostat for my old pellet stove. Your project is what I need but I need also to add a temperature probe that can switch on or off the stove.
Have you got any news about the logzy question?

Thanks in advance for your answer and for your great job.
jernst says:

January 26, 2013 at 11:54

Hi logzy,

glad you like it. It sounds like you need to find yourself a PHP hacker. I’d drive the thermostat functionality off cron, just like I do for the timer. If the cron job runs, say, every 10 minutes, compares the temperatures and then takes appropriate action, you might get what you want. So for the rasptimer code, you’d have to plug into the code that writes as well as reads the cron files, and of course add a web page (or several) to edit your parameters, and/or switch everything on/off. It’s more of a 1-day than 1-hour kind of project, but not particularly hard.

For curiosity, what are you using to measure the pool water temperature and how are you connecting it to the Raspberry Pi?
1. logzy says:
  
  January 26, 2013 at 15:57
  
  For temperature measurement im going to use the DS18B20 connected onto GPIO #4.
  For the cables ill probably use ethernet cable or similar. One sensor will be about 4m of cable and the other about 15m of cable.
  1. jernst says:
    
    January 27, 2013 at 20:40
    
    Very cute chip! And there’s even kernel support as it seems.
    
    I wouldn’t mind being able to capture my pool’s water temperature, too, but haven’t figured out a good place where to place the sensor given that the pipes are under pressure.
  2. logzy says:
    
    January 28, 2013 at 20:29
    
    Yes it is a nice chip and the kernel support is the biggest bonus.
    Ive been hacking away and slowly learning PHP as i go. Still got a few things to sort out but have found someone to help me.
    I will soon have a full functioning system for the pool controlling the main filter pump and the solar heating pump as well.
    Im going to also line graph the roof temperature and the pool temperature plotted on the one chart so i can see the rate of heating in relation to the roof temp.
    
    My current pool temp sensor is on the suction line of the solar pump however this isnt ideal as the water in the pipe cools quicker that the pool water when the pump is not operating. Im going to drop the new sensor in the skimmer box so its reading from the mass of pool water instead of whats in the pipe
logzy says:

January 26, 2013 at 04:01

Hello,

Love your pool timer project. I would also like to control the pool using the RPi.
I dont have a sweeper pump, just a main pump and the solar heating pump.

Ive been studying your code trying to work out how i would control the solar heating pump by temperature instead of using a time schedule.

For temperature logging i can use this which writes the temperatures to a text file
http://www.trainelectronics.com/RaspberryPi/Graph_Temperature/index.html

Where im stuck is with the PHP whereby i would need to compare the roof temperature with the water temperature and the desired temperature which would be entered on the webpage.

The RPi would then turn the solar pump either on or off based on a couple of rules;
If roof temp is > than water temp by 10 deg C and desired temp is > water temp then turn pump on.
If water temp = desired temp then turn pump off.
If roof temp is < than water temp by 10 deg C then turn pump off.
Once the pump has turned off it would remain off for 10 mins to prevent the constant on/ off cycles when limits are being reached

Given your PHP knowledge evident from your project how much work do you think is required for me to achieve what im looking for. Is this one hour of work or 8 hours of work, is this something you would be interested in doing.

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