Hello everyone, in this project I wanna show you how to make 2-Channel Thermostat. This project is based on Atmega 328P(Arduino Uno). My thermostat can measure temperature from 0 to 255 °C on 2 separate channels. In the future I am gonna convert my cnc machine to 3dprinter and use this thermostat to control temperatute of the extruder and the table.

I made video and step by step instruction how to make it.

So, let's go to work :)

Materials:

- Electrocnic parts
- Enclosure box
- Arduino
- Circuit board blanks

Tools:

- Soldering iron
- Tin
- Pliers
- Drill

Step 1: Watch the Video

Video will give you a good overview on how to create such a 2-Channel Thermostat. But the following steps will still contain some extra useful information.

Step 2: About Schematic

Schematic in eagle and pdf file you can download below.
How you can see Thermostat is based on Atmega 328P that same is used in Arduino Uno. Temperature is read from 100K thermistor (0-255°C) . There are 2 thermistors and 2 relays for heaters. Additionally I made two 12V outputs and two free outputs pins from aduino. This pins you can use to make any change in schematic. To power thermostat I used 12v transformer. To control thermostat I made 3 potentiometrs. Two to set temperatures and 1 to adjust hysteresis (from 0 to 9 °C). To set and read all values I used 16x2 LCD blue display.

Step 3: Make PCB

First you have to make PCB board. Template in Pdf and Eagle files to download in previous step. To make pcb I used toner transfer method. It is very easy and gives very good results. When excess of copper is removed, just drill the holes.

Step 4: Soldering Time

Now solder all electronic components to PCB and control board is ready :)

Step 5: Programming

Time to code. To move code to Atmega use this tutorial created by Arduino. I made 2 types of code. First 2-channel thermostat with hysteresis, and second only 1-channel with hysteresis. You can download code below.