“Did I turn the electric range (stove) off?!?” Are you tired of having to rush back home when you are already late for appointment, to find your stove was actually off? Or tired of the shockingly high bills at the end of the month due to the hours that the stove was left on by mistake”
Here is an easy hack for you that is cheap and easy to do…
Even though most ranges are not smart enough to warn if they are kept ON for an extended period of time, they do have two LED indicators that will be the key for this hack. Usually one LED is for the hot surface – which stays ON as long as the surface of the cooktop is hot. The other one gets turned ON whenever any of the switches/heating elements are turned ON and gets turned OFF as soon as all the switches/heating elements are turned OFF. That’s our trigger. A photocell can be used to detect the status of this LED, update the status of a device in a controller (Vera Edge in this case) and also set an alarm after a user-specified/default time period.
This device has the following unique functions:
The photocell is placed on top of the status LED to detect the light from the status LED of the range. With the range ON/OFF it sends a HIGH/LOW signal to the attached Nano. The Nano then sends this information to the Vera device through an Ethernet Shield Gateway and the device status gets updated. It sends email/notification to the user based on the set Scenes in Vera. It also actives a timer in the Nano and sets off a buzzer (beeper) after the set time expires. By default, the buzzer gets activated after an hour from the time the range is turned ON. User can change the timer time to a greater value (2, 3, 4 or 5 hours) by using a single push button switch. A LED indicates which time the timer is set to.
If the range is kept ON for the time period that was set, the buzzer gets activated and status gets updated in Vera device. Once the range is turned OFF everything gets reset and Nano waits for next trigger. The photocell sensor is placed on the stove using a magnetic housing allowing for an easy removal during cleaning.
The following materials were used in this project:
Opportunities to Improve:
A couple of opportunities to improve include:
Demo: For demo/video the alarm time was changed to 10 seconds for the default alarm (check code for comments). After verifying first alarm, time was changed to 30 seconds using pushbutton. Second alarm was verified in about 30 seconds. Stove was then turned off and controller reset everything to default.
Thanks for reading.
|Qty||Value||Device||Package||Parts||Description||MF||MPN||Aliexpress or ebay link|
|2||Transistor||2N3904||For buzzer and Photocell Input|
|1||Temp and Humidity Sensoe||AM2320||Reading Kitchen Temp & Humidity|
|2||10uf, 25V or 4.7uf, 16V||Capacitor||Attached to 3.3v and 5v Power|
|1||220 ohm||Resistor||For indicator LEDs|
|1||4.7k||Resistor||For Temperature sensor|
|1||1k||Resistor||Attached to buzzer driving transistor|
|1||100k or smaller||Trimmer Pot||For adjusting photocell input|
|1||Buzzer||4v - 12v||For alarm / beeps|
|1||NRF24L01||Wireless Radio||For wireless communication with ethernet gateway and vera|
|1||ATmega328||Arduino Nano||Sensor controller|
|1||Pushbutton||For selecting time for timer|