Hot Tub Temperature Control

Projects General Guidance
20

Update....

Well work commitments and other projects have held me back a little, and I keep adding new features, but progress is now speeding up , mainly due to the tub being empty and the old controller is now on my workbench!

First of all I would like to point out that I have changed the Arduiono from a UNO to a MEGA2560, A few reasons,

  1. I was running short of RAM,
  2. I thought this RAM shortage was truncating my received SMS messages,
  3. Although I had just enough I/O Pins with the UNO, I have some expansions plans, more on that later

so what's working...

operation modes including , Frost Protect, Standby, Manual and Rundown

temperature control , frost protect temp, standby and runtime temps over temp in software

manual control of Spa functions, pumps etc

Front panel display, buttons, beeper etc

Basic current management, my original tub controller, would only allow certain combinations of pumps/ heater blower to be operated simultaneously, I have replicated this in the control logic

SMS

SMS status, send you a SMS back wit stats

SMS mode, to flip the tub to a new mode

SMS GOXX, to set a new temp

SMS Time , set the RTC from text message header

So what's the hold up ? you may ask...

sometimes the SMS module will not respond, so I think I need to write a routine to query it every hour or so and check its status , if I don't get a response I will fire a relay to do a hard reset on the SMS module

I think I need to implement a watch dog timer , this is supported so its not a big update

there is an Ozone receptacle on the old controller so need to add support for that .

the Pressure switch which will just be wired in series with the heater relay line, I think I will now monitor this in software too, adding an HeaterEnable to the logic

I need to write a menu to set up the basic config, things like default standby temp, clock setting , lighting etc

So in actual fact there is not a lot to do, and the pressure is now really on, the tub is drained , and after only one week I am missing it !

The old spa control panel has been ripped to bits , chopped down until I am just left with the trim, this I will re use when building the new topside control panel, which if it all comes together how I plan will look nice and professional ..

I am hoping around a week from now it will be done!