Open Heat-Pad Controller

Heat-Pad Controller using Arduino and Thermistor.

This project is an example of multi-tasking on an Arduino using a timer. I tried NOT to include OOP concept, to keep it as simple as possible for students. However, please feel free to improve it as you like.

Setup

For Platform.IO clone this project to your local machine and you're good to go.

For Arduino Create your own new sketch then copy all the source code in main.cpp to it.

Terminal

Connect the board to any Serial Port Terminal (i.e. Putty, Realterm) with Baudrate at 115200.

You should see something like this on your terminal.

>>

If there are lots of numbers flooding on your screen, type 'stop' and press enter, to stop all tasks.

For first time usage, following these steps is recommended.

1. type default to load default profile.

   >> default
   
   Set Default to Current Profile... DONE
   
   Current Profile
   --------------------
   11 - setpointTemp : 40.00
   12 - isAutorunEnabled : 0
   13 - isPlottingTaskEnabled : 0
   
   21 - ADC_MAX : 1023
   22 - THERMISTER_PIN : 0
   23 - THERMISTER_REF_RESISTER : 9960.00
   24 - THERMISTER_ROOM_RESISTANCE : 10000.00
   25 - THERMISTER_ROOM_TEMP : 25.00
   26 - THERMISTER_COEF_B : 2988.64
   
   31 - DENOISE_ORDER: 1
   32 - DENOISE_DIFF_LIMIT : 0.02
   41 - CONTROLLER_PWM_MAX : 255
   42 - CONTROLLER_PWM_PIN : 6
   43 - CONTROLLER_INA_PIN : 7
   44 - CONTROLLER_INB_PIN : 8
   
   51 - kP : 500.00
   52 - kI : 0.00
   53 - kD : 0.00
   
   >>

2. type save to save default profile to the storage.

   >> save
   Saving Profile to storage... DONE
   
   Current Profile
   --------------------
   11 - setpointTemp : 40.00
   12 - isAutorunEnabled : 0
   13 - isPlottingTaskEnabled : 0
   
   21 - ADC_MAX : 1023
   22 - THERMISTER_PIN : 0
   23 - THERMISTER_REF_RESISTER : 9960.00
   24 - THERMISTER_ROOM_RESISTANCE : 10000.00
   25 - THERMISTER_ROOM_TEMP : 25.00
   26 - THERMISTER_COEF_B : 2988.64
   
   31 - DENOISE_ORDER: 1
   32 - DENOISE_DIFF_LIMIT : 0.02
   41 - CONTROLLER_PWM_MAX : 255
   42 - CONTROLLER_PWM_PIN : 6
   43 - CONTROLLER_INA_PIN : 7
   44 - CONTROLLER_INB_PIN : 8
   
   51 - kP : 500.00
   52 - kI : 0.00
   53 - kD : 0.00
   
   >>

For more information, type help

Tested Hardware

• MCU: Arduino NANO v.3

• Thermistor: 10k @ 25 °C NTC Type

• Heat-Pad: Custom PCB Heatbed

• Power Control: 24V 3A Motor Driver Board

• Power Supply: 24V 3A or Battery with Regulator

• Power Regulator: 5V 1A (or over) for MCU (For standalone usage)

1. Thermistor is serially connected with 10k Ohms Resistor between 5V and Ground Pin on MCU.

   |---------| -- 5V --------------||
   |         |                     ||  ...... Thermister
   | Aruino  | -- Analog 0 -----||-||
   |         |                  || .......... 10K Resistor
   |---------| -- GND ----------||
   
   * if Thermnistor and R 10k are swapped,
     use invert measuering code on 'getResistance()' instread.
   

2. Motor Driver connected with MCU on Digital Pin 6, 7, 8 For PWM, Direction A, Direction B respectively.

   |---------| -- Digital 6 -------- PWM --- |---------------| 
   |         |                               |               |---------------- V Supply +
   |         | -- Digital 7 -------- IN A -- |               |---------------- V Supply -
   | Arduino |                               |  Motor Driver |
   |         | -- Digital 8 -------- IN B -- |               |----------------- HeatBed +
   |         |                               |               |----------------- HeatBed -
   |---------| -- GND -------------- Gnd --- |---------------|
   
   ** For 'Power Side', twisted wire is recommended.        |-------- Power Side -------|
   

Plotting

if 13 - isPlottingTaskEnabled is enabled ( Value = 1) then value of Current_Temperature and Setpoint Temperature will be periodically shown like this.

26.41 40.00
26.41 40.00
26.37 40.00
26.33 40.00
26.29 40.00
26.33 40.00
26.35 40.00
26.35 40.00
...

you can use Serial Plotter on Arduino IDE ( Tools > Serial Plotter ) to plot these value in real time.