Smart Power Outlet

When I built these projects, I was still very new to both software and hardware development so there are many visible flaws and imperfections. If you want to get an idea of my current progress, please check the latest projects!

V1: October, 2017

This device uses “Dual Tone Multi Frequency (DTMF)” of cellular network systems to control any electrical appliance! Suppose, you’ve come to a party but you don’t remember if you had switched off the electric stove before you left.

No one wants to leave a party early, right?

So, if the electric stove was connected to this device, you can just call its number and press a digit to turn off the stove if wasn’t already.

That’s what it precisely does, letting you control appliances with just a phone call.

Technical Details

The hardware part consists of:

  • Arduino Uno, to control everything.
  • 16×2 LCD display for showing relevant information.
  • DTMF (Dual Tone Multi-Frequency) module that can recognize the tones of numbers pressed over a phone call.
  • Relay module, to control the appliance.

In a nutshell, the DTMF module is connected to a phone (that is set tp receive calls automatically), picks up the numbers that were pressed by the user on the other end and passes them to the Arduino. The Arduino then turns the appliance on or off using the relay module – depending on what number was pressed by the user.

Things I wish I did better

  • Making a safer enclosure. The PVC sheet enclosure was a fire hazard itself. However, I did fix this in the second version.
  • Using a GSM module to receive calls or SMS instead of requiring a phone to be connected to the power outlet all the time.

V2: June, 2018

A few months after finishing version 1, I made an improved version.

This was equipped with temperature sensors. If any of them detects fire, the Smart Power Outlet cuts off power immediately and triggers a fire alarm. My reasoning was that if the fire is caused by one of the connected appliances, cutting off power immediately should stop the fire from spreading.

Just like V1, is built-in DTMF technology that lets the user control connected appliances with just a phone call. And last but not the least, there is also a surge protection function which protects connected appliances from any power surge.

Technical Details

The hardware part consists of:

  • Arduino Uno, to control everything.
  • DTMF (Dual Tone Multi-Frequency) module that can recognize the tones of numbers pressed over a phone call.
  • 4 channel Relay module, to control the appliances.
  • Two thermistors, to detect fire.
  • Buzzer, to act as the alarm.

To summarize, the DTMF module is linked to a phone that automatically receives calls, detects the numbers dialed by the user, and transmits them to the Arduino. Based on the number pressed, the Arduino uses the relay module to turn the appliance on or off. In case of a fire, the thermistors can sense the temperature and immediately cut off power to all connected appliances. And of course, triggering the alarm.

The surge protection function was achieved simply by placing a delay between the startup of the Smart Power Outlet and enabling the power connections to all connected appliances.

Things I wish I did better

  • Fixing the thermistors more rigidly and adding some IR sensors as well – to prevent any false triggers generated by the thermistors.
  • Using a GSM module to receive calls or SMS instead of requiring a phone to be connected to the power outlet all the time.

In