Smart Mirror

Amazon Alexa can be used in conjunction with the particle to communicate with electronic devices. Thus, Alexa can be used to control LED’s, return the temperature, or even control a cat toy.


Saagar M

Area of Interest

Computer Science

Monta Vista HS


Rising Senior

Starter Project


For my starter project, I built the TV-B-GONE. This device is a nearly universal remote that can turn off almost any brand of TV like Samsung, Sharp, and Philips from up to 150 feet.

How To Use

The way you use this contraption is you simply point the device so that the IR LEDs are aimed at the tv, press the button and the TV should turn off. To know if it is working, the green LED next to the button should blink, indicating it is sending a signal to the TV.

How It Works

When the power supply is connected and two double A batteries are placed in this battery holder, it supplies the circuit with a current. The button that you press is used to reset the circuit and essentially turns the circuit on and off. When the circuit is turned on, the TV-B-Gone sends a signal that is decoded as an off signal by the TV. This off code is found by the micro-controller by running pre-programmed code to find the specific off signal for each TV. So once the right code is found by the micro-controller, the transistors amplify the signal and reroute it to the IR LEDs which emits an infrared light hits that the TV and is detected as an “off” function which turns off the TV.

Important Components and Their Functions

Circuit board: connects multiple electric components together and allows an electric current to flow effectively throughout the circuit without wires

Micro-controller: Using the pre-programmed code, it finds the correct code to send the off signal to the specific TV

Battery holder: Holds two double A batteries, which then supplies a current between 400mA and 1000mA to the circuit

Button: used to reset the circuit and essentially turns the circuit on and off

IR LEDs: have a similar wavelength to the wavelengths used in TV remotes and because there are both blue and clear IR LEDs which have different ranges, it can hit a variety of TVs and therefore can send the signal through the IR light

Ceramic Oscillator: generates an oscillating signal of a specific frequency

Ceramic Capacitor: monitors the flow of current by charging and discharging charge and allows only specific AC frequencies

NPN transistors: used to regulate current, making sure there is not too much or too little and indicates it by turning on the IR LEDs


During the building process, I faced a couple of problems. This was the first time I learned to solder and I had some trouble soldering the components onto the circuit. As a result, while I had some beautiful, strong joints, I had a couple of weak joints and some parts that were stuck together. Having different parts stuck together can be bad because it can cause the circuit to short-circuit. Therefore, I had to desolder some parts which was a very difficult, painstaking process and took multiple attempts to finally fix the joints.

What I Learned

Overall, this project was very beneficial for me because I not only learned about the different parts of the circuit like the micro-controller, capacitor, and resistor, but I also gained some exposure to soldering and desoldering components to the circuit board.

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