Introduction
Statement of Purpose
By creating a basic FM transmitter and receiver, we hope to understand how hardware can be used to translate sound waves into radio waves and vice versa. Knowledge of radios can unlock a variety of different wireless projects that will be discussed in the next phases of this multi-part proposal. We hope that the project will give us a basic idea of the types of projects that we will be involved in for classes like ECE 210.
Background Research
Through various physics classes we are able to understand the basics of the electromagnetic waves that carry radio signals, and through ECE 110 we possess the skills needed to analyze the waves coming from a radio to make sure the device is working as intended. We have found that most DIY schematics for radios apply to FM radios, so we decided to create an FM radio rather than an AM radio due to the availability of information in case one schematic from the internet doesn’t work. This idea came from the previous proposal to create a digital radio jammer. The complexity of the prior project led us to this simpler progression of smaller projects.
Design Details
Block Diagram / Flow Chart
-The oscillator uses an inductor and capacitor to produce a simple sine wave that can be modeled by the equation F = 1/(2*pi*sqrt(L*C)) where L represents capacitance in henrys and C represents capacitance in farads.
-The transistor combines the signals from the microphone and oscillator to create a signal that can be transmitted over radio.
-The oscillator uses an inductor and capacitor to produce a simple sine wave that can be modeled by the equation F = 1/(2*pi*sqrt(L*C)) where L represents capacitance in henrys and C represents capacitance in farads.
-The transistor translates the sine wave from the oscillator and the signal from the antenna into a sound wave.
Parts
The only parts that don’t already come with the ECE 110 lab kit are wire that can be turned into an air-coil inductor, two 30pF variable capacitors, and an LM386 (though an LM358 from the ECE 110 lab kit can probably perform the same function).Possible Challenges
Like the 110 lab, most challenges should come with troubleshooting breadboard circuits since the design portion of the project is already done.References
How to make a FM Radio. (2017). [DVD] Directed by Keystone Science. Provo, Ut.
How to make a FM Transmitter. (2017). [DVD] Directed by Keystone Science. Provo, Ut.
En.wikipedia.org. (2020). FM broadcasting. [online] Available at:
https://en.wikipedia.org/wiki/FM_broadcasting [Accessed 26 Feb. 2020].
