Web-enabled Arduino Hot Tub controller / monitor / internet bridge
the software is called hottube because it's a hot tub on the internet, and the internet is a series of tubes.
Using X-Board V2.0 (SKU:DFR0162) with Ethernet:WIZ5100 and Arduino UNO Bootloader
branch "master" is for use with an external water heater that is triggered by water flow from the pump.
branch "lectric" is for controlling an electric heater through a solid-state relay, and an electric water pump through a different solid state relay (even if they can't share, if one's 240v the other is 120v)
reading temperature using a Waterproof DS18B20 Digital temperature sensor (there are also thermistors before and after the electric heating element)
example program for DS18B20: http://bildr.org/2011/07/ds18b20-arduino/
output temperature to an analog temperature gauge (from the exploratorium) using PWM on pin D9
also controls hot tub jets with a button or pullstring, short pull to add time, long pull to cancel.
the following instructions are ONLY necessary if you don't want to use the ordinary Arduino IDE to flash the program onto your arduino!!!!!!!!!!!!
installing the toolchain
First install the standard avr toolchain:
$ sudo apt-get install python-pip gcc-avr avr-libc binutils-avr avrdude
build and flash
Plug in the arduino over usb (and make sure you have permission to write to /dev/ttyACM0), then do: