DIY Whirlpool with Cayenne controller


About This Project

I´ve made a DIY-Garden-Whirlpool out of an old IBC-Tank with 1000l and i want to control all stuff via web.
I´ve used in an earlier version webiopi for this but now i´ve changed all over here to Cayenne.
The Whirlpool (sadly currently without whirl) is equipped with a small filterpump and a heater. I´ve checked multiple methods of heating the 800l water to temperatures of about 36-40 Grad Celsius. It was to expensive to get this amount of water hot all the time. The electrical heater are only 2kW which could ± heat only 3Grad/h.
After a while of studying the net i was thinking about a Webasto Diesel car heater with 5kW which i can run with Heizöl.
I could get one cheap on ebay.

After a few tests with about 100l water i was ready to get this into my whirlpool.
The water flow is Pool -> filterpump -> heater -> Pool

There are 3 Temperaturesensors:

  • Water temperature
  • Heater output temperature
  • air temperature

Due to electrical safety, i´ve no 220V at the pool, only on the controlerbox which is about 3m away.
The filterpump works with 12V AC from its own power supply and the Webasto stand heater works with 12V DC.

What’s Connected

  1. Raspberry Pi B+
  2. 12V powersupply with 17A current max
  3. Car 12V to 5V-USB Stepdown for the Pi
  4. relaisboard with 2 relais
  5. Box for installation
  6. 3 x DS18B20 Temperatursensor in waterproof housing

Triggers & Alerts

I have to ensure that the heater can not be switched on without switching on the pump which pumps the water through the heater. So one trigger says “if Relais Heater on than Relais Pump on” and another one is “if Relais Pump off than Relais Heater off”.

Another point is that the temperature in the pool should not rise above 40Grad Celsius so i have set up a trigger which takes the heater offline when the watertemp is over 38Grad Celsius


I´m switching the filterpump off during nighttimes to minimize the temperature loss.
For security reasons this trigger switches also the heater off if it may be on.

Dashboard Screenshots

Photos of the Project

The things on the photos are not final builds. Most is "work-in-progress"
So i´ve now a new housing for the controller, power supplys which is realy waterproof :wink:


This is awesome! Glad you were able to transition from WebIOPi to Cayenne. @eptak (creator of WebIOPi) is actually on the Cayenne team, not sure if you were aware of that.

Do you have plans to add some sensors etc. to a garden too?

Thank you for submitting this!


Yep, i know that the webiopi is now Cayenne :wink:

I have no idea what else i could do with some sensors. I own already a weatherstation so i don’t need anything of that.

My pool is a bit of a never ending project. A fwe weeks ago i bought 50m of black gardenhose to build a diy solar heater. It works perfect with a second pump. But sadly i own only a 12V divepump from an caravan. And i dont want to have a divepump inside of the pool. So i had this about 2 weeks and now i heat the pool again with diesel.

What i realy need is a bit more flexability with the triggers.
A example: the solar heater on the roof has 1 temperatursensor and the pool has another one. Now i need a trigger where i could say: if temperature on solar is 10degree above pooltemperature than switch on the solarpump.

Oh, one sensor would be nice: a ultrasonic distance sensor. With that one i could build a simple waterlevel and heater-fuel level sensor.

If fuel is nearly empty than power off the heater
If pool is unter level x than send a sms to me