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Wifi controller for car auxiliary heater

Group 11: Sami Torppa

1. 1. Project description 

My car has an auxiliary heater which can be operated only from inside the car. The purpose of this project is to build a wifi-controlled system that operates the heater and also observes circumstances.

I have bought a module that enables to control CAN-bus controlled heater with a separate controller. Arduino Uno will be the base of the control unit. The heater will be operated by RemoteXY. Users can set the heater on/off, preset a heating timer, check the car battery voltage, or observe temperatures inside the car. 

1.1.  Hardware

ComponentBought fromPrice 
Arduino Uno R3Aliexpress (1/2020)5,86 €
ESP8266 WIFI modulePartco7,90 €
TMP36 temperature sensorPartco2,95 €
Crowtail Voltage Sensor 2.0 (0-25V)Partco6,57 €
5V relay (10A)Aliexpress (1/2020)19,46 €*
Voltage regulator MP2307Partco2,95 €
Volvo Accessory Electronic Module (AEM) 120,00 €

*) Included in Arduino starter kit

The total costs of hardware were approximately 150 euros.

(click to enlarge image)

Components listed from top to bottom:

  • Wifi-module
  • Temperature sensor
  • Breadboard
  • Arduino
  • Voltage sensor
  • Relay
  • Voltage regulator

1.2. 4. Assembly

The Arduino gets power from the car battery and the battery voltage is up to 14,4 volts. Recommended operating voltage for Arduino is 5-12 volts and that is why I connected the voltage regulator.

The voltage sensor and the temperature sensor are analog sensors. These sensors are connected to Arduinos analog input A0 and A1. The wifi module and the relay module are connected to digital outputs 0, 1, and 4. The wifi module is communicating with the Arduino by using a serial bus. Arduino has serial receiving and transmitting pins in digital pin numbers 0 and 1. That is why there is only one way to connect the wifi module. Only the relay module needs a 5-volt input voltage. All other components were running with 3,3 volts. 

I used hot glue to ensure wiring connections to the breadboard. 

1.3.  RemoteXY

RemoteXY allows operating Arduino over the internet. In the free version, you can use only 5 objects on the "desktop". With purchasing 8,49 € there is a possibility to add buttons, graphs, indicators, and labels indefinitely. I upgrade this PRO-version and designed an application that has two pages. In the first page, the user has three operating modes to choose from:

  1.  Direct start (heater is running until the car starts)
  2. Heating to the set temperature
  3. Heating for the set time

The heater stops also if the car battery voltage drops below 12,5 volts or after one hour of heating.

The user can set an alarm when the heating is ready by pressing the red speaker icon. Bellow the speaker icon, is the current values of the car inside temperature and the battery voltage.

On the second page, the user can observe the history of the battery voltage level and the car's inside temperature. The application saves the collected data from the last seven days. 

1.4. Program code

1.5. Current challenges

While testing the new code for RemoteXY PRO, the voltage regulator stopped working. After that Arduino does not communicate with the computer and RemoteXY didn't have a connection anymore. I guess that the voltage regulator produced a voltage spike and it was too much for the Arduino.

Because of the long-lasting corona-virus infection, I wasn't able to print housing for the Arduino and the sensors yet. 

1.6. Video


1.7. Coming soon...

  • New Arduino board and final testing with RemoteXY PRO
  • Housing for the hardware

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  File Modified
PNG File image2022-3-15_4-6-46.png Mar 15, 2022 by Sami Torppa
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