Overview

The megaRF is a microcontrollerboard, that is compatible with the Arduino-IDE. It is based on the Atmega328P and has a RFM12 radio module to communicate wireless with other megaRF boards.

Programming & Library

The ATMega328P has a preloaded Arduino-bootloader, so all you need to get started is a USB-Serial adapter.

There is a simple library for the RFM12 radio module, you can find it here: https://github.com/heye/rfm12 or here: megaRF.zip

Sending & Receiving

Sending and receiving data is very simple! This is an example on how to send a short text every 100ms.

void setup(){
}

void loop(){  
  //try to enque new packet for transmit
  RF.send("wake up neo...");

  //call this tick function periodically, it will take care of collision avoidance, 
  //start transferring packets and check if there are any received packets
  RF.tick();  
  delay(100);
}

The following example waits for transmissions and prints the result on a serial connection.

void setup(){ 
  //start the serial connection 
  Serial.begin(19200);

  //register callback function
  RF.onReceive(receiveEvent);
}

void loop(){    
  RF.tick();
  delay(10);
}

void receiveEvent(void){
  //print received data
  Serial.println(RF.getBuffer());
}

Details

The Atmega328 runs at 3.3V

• Controller: ATmega328P
• Clock Speed: 8MHz
• RAM: 2KB
• Flash: 32KB
• Operating Voltage: 3.3V
• Input Voltage(power version): 5-7V (micro-USB or raw input pin)
• Input Voltage(regular version): 3.3V
• Radio module: HopeRF RFM12 433MHz
• Size: 25.4mm x 41.91mm

Eagle schematic & boardfile

IO & RFM12

The pins MISO, MOSI, SCK, D2 and D10 are used for communication with the radio module and should not be used in your own sketches.

Use Cases

Use these boards, wherever you need some wirelessly connected Arduinos, I am using them for home automation, wireless sensors, and a lot of other simple projects.