Wireless RF Speakers


CAD, Electronics, Programming, Rapid Prototyping

This is my favorite project that I have done thus far. The purpose of this project was to gain a further understanding of op-amps, RF filters, electronic waveforms, and RF signals. The final product is a wireless RF speaker that is just about consumer product worthy.

How it works

The M2 micro-controller at the center of the circuit both receives and sends signals. Incoming is a small packet of three ints (frequency1, frequency2, duration) which is received by the mRF module and sent to the micro-controller, there the signal is converted into a PWM (pulse-width modulation) sine wave and output through one of the pins. This signal then goes through band pass filter that turns it into a smooth sinewave and amplified, ultimately going through a NPN and PNP transistor amp to power the speaker.

Design

The entire housing was designed from the ground up in SolidWorks. The trim, fittings, and speaker grill were 3D printed in white, whereas the housing panels were laser cut from MDF (medium density fiberboard). The most difficult thing to design was the speaker grill which required a combination of 3D curves and bounded extrusions to be successfully modeled in Solidworks.

The code for this project can be viewed on GitHub

Materials Used

MDF, PLA, Perfboard, M2 Microcontroller, Voltage Regulator, Op-Amp, Assorted Resistors and Capacitors

Tools Used

Oscilloscope, DC Power Source, Atmel Studio, Laser Cutter, Makerbot Replicator 2, Solder, Hot Glue Gun

Project Duration

2 Weeks

Date

October 2014