Couple of arduino sketckes to control a heater system at home
This project consist in two different parts:
Thermostat.ino
Should be uploaded to an atmega328P.
Can be any arduino but for my project I used a bare atmega328P running at 8MHz and powered at 3.3V (see hardware part)
Libraries needed:
1- SPI (included on arduino IDE)
2- RF24 (https://github.com/TMRh20/RF24)
3- Lowpower (https://github.com/rocketscream/Low-Power)
4- DS3231 (http://www.rinkydinkelectronics.com/library.php?id=73)
5- PCD8544 (https://github.com/carlosefr/pcd8544/releases)
Receiver.ino
Uploaded to another atmega328P
Libraries needed:
1- SPI (included on arduino IDE)
2- RF24 (https://github.com/TMRh20/RF24)
There are some comments in the code, that can help to understand how they work.
Unit 1 (controller unit) consists in the following parts:
1- Atmega328P microcontroller
2- nokia 5110 lcd display
3- nrf24l01+ module
4- RTC DS3231
5- thermistor 10K
6- Battery holder (3xAAA in my case)
7- voltaje regulator (I'm using a XC6206p332, but any low dropout regulator with los quiescent current is fine
8- Resistors (2x 220 as pull-up for pushbuttons / 10K for RST / 10K for the thermistor / 220 for the backlight)
9- Capacitors (2x 100 nF decoupling in the VCC-GND of atmega / 100 nF for the rest line of the FTDI cable)
10- Two push buttons
11- Stripboard
12- Cables and headers to connect all the components)
13- A FTDI adaptor for programming if ussing a bare Atmega328p o arduino pro-mini.
14- An enclosure to nicely fit all those componentes.
Unit 2 (receiver unit) consists in the following parts:
1- Arduino pro-mini running a 8MHz and 3.3V.
2- Relay module (5V controlled via transistor with an arduino pin (HIGH=3.3V).
3- Led and resitor to show if heater is on or off
4- Switch with three possitions (1- Auto mode / 2- Manual ON / 3- Manual OFF)
5- Power suppply (5V 1A)
6- Regulator (AMS1117-3.3V)
7- nrf24l01+ module
8- Cables and some connectors
9- Terminal headers for the connection of the heater cables (always check the specification of the heater)
10- An enclosure.
I provide also the fritzing file for the thermostat unit.