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

https://www.dfrobot.com/wiki/index.php/X-Board_V2_(SKU:DFR0162)

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)

https://www.adafruit.com/products/381

example program for DS18B20: https://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.

First install the standard avr toolchain:

$ sudo apt-get install python-pip gcc-avr avr-libc binutils-avr avrdude

Plug in the arduino over usb (and make sure you have permission to write to /dev/ttyACM0), then do:

$ ./make.sh