A very small Open source Digital Walkie Talkie project made based on ATMEGA8 and a well known RFM12B RF module to send & receive voiceDesigned by Senior Electron LLC, Ships from United States of America
You will get 2 bare boards + schematic + pcb + source code + list of components and you can do it your self easily As you understood from the project title , this is an Educational Open Source Dig...Read More…
you will get 2 bare boards + schematic + pcb + source code + list of components and you can do it your self easily
As you understood from the project title , this is an Educational Open Source Digital Walkie Talkie that sends audio signal with a digital data transceiver module !!!!!
i used a popular and very common RF module from HopeRF with the part number RFM12B which is a fast SPI data transceiver .
as you may know this module is a high speed data transceiver module but not for audio !!!!
well that is the trick !
the most important thing in this project is, i get the analog signal that comes from the Micro Phone with AVR ATMEGA8A Micro Controller , convert the analog signal to the digital value with the internal ADC and then make data Packets and send the digital data packets thru SPI port to the RF module.
and on the receiver side, the RF Module receives data , sends the Digital data thru SPI Port to the micro controller and the micro controller will convert the Digital data to analog with the PWM output ! . yes PWM
on this project you will learn how to convert analog voice to digital value , getting rid of the the zero cross distortion , making FIFO buffer , use PWM as a digital to analog converter and how to work with SPI port for sending data packets to the RFM12B module
because the data is digital , we are able to send data with the audio as will . and also we can change the carrier frequency or change the identification codes on each unit so we can set different groups with unique code . then each walkie talkie can connect to the walkie talkies with the same code
we have a microphone and a speaker on each board , and a switch that change the system mode from receiver to transmitter when we hold the switch .
so you hold the switch and talk . exactely like a real walkie talkie
the sound quality is very good for human voice
the circuit is very simple and works from 2.7 to 5.5 volts . so 2 or 3 small AAA battery will be enough to drive it
The source code is written in BASCOM-AVR that is a very easy to use and simple Compiler for AVR and many students or even professionals are using that
The BOM list is attached to the Project and there is not any Fancy or hard to find Part on the BOM . all of the parts are common and easy to find
there is a Programing port on the board that you can connect any standard ISP AVR programmer to the board and program the Micro controller on the board
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