Introduction: LinkIt ONE RF Communication

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A great push to the home automation field was introduced when you could control your electronics using wireless communication. Bluetooth and wifi are great, but they make things a little bit more complicated.

Sometimes the easiest solution is playing with raw wireless communication. For example this instructable proves the ability to communicate between an Arduino and a MediaTek LinkIt ONE board. The Arduino is connected to a transmitter and sends a 1-second-HIGH-signal every 2 seconds, where the MediaTek LinkIt ONE board, is connected to a receiver, and whenever it receives a HIGH signal, it turns on the LED.

Step 1: Supplies

We use the MediaTek Linkit ONE micro controller. This board is equipped with ARMv7, 4GB Ram, bluetooth, GSM, GPRS and Wifi. I was lucky enough to put my hands on this board, and I can't leave it :)

Back to our project, I have used the following things:

Step 2: Preparing the Transmitter

For the transmitter to be able communicate with the receiver, we need to build an external antenna. I have found that aluminium foil is good enough for the receiver to be able to receive the communication.

On the transmitter board, you can see a small hole on the upper right corner with the caption ANT, which stands for antenna. Use a foil in order to connect it as an antenna, that touches the inside of the ANT hole.

Step 3: Wiring

Transmitter (Arduino Leonardo):

  • Arduino 5V Vcc connected to Transmitter's Vcc
  • Arduino GND connected to Transmitter's GND.
  • Arduino Digital Pin 4 connected to Transmitter's DATA pin (some versions has ATAD written on them, chinese typo :P)

Receiver (MediaTek LinkIt ONE):

  • LinkIt ONE 5V Vcc connected to Receiver's Vcc.
  • LinkIt ONE GND connected to Receiver's GND.
  • LinkIt ONE Analog Pin A0 connected to Receiver's Data (the pin next to the GND pin).
  • LinkIt ONE Digital Pin 4 connected to the LED's longer leg.
  • LinkIt ONE GND connect to the LED's shorter leg through a resistor.

Step 4: Coding

Transmitter:

#define TX_PIN 4

void setup() {

pinMode(TX_PIN, OUTPUT);

}

void loop() {

digitalWrite(TX_PIN, HIGH);

delay(1000);

digitalWrite(TX_PIN, LOW);

delay(1000);

}

Code can be found in TX.ino


Receiver:

#define RX_PIN A0
#define LED_PIN 4

void setup() {

Serial.begin(9600);

pinMode(LED_PIN, OUTPUT);

}

void loop() {

long data = analogRead(RX_PIN);

if (data > 65) {

digitalWrite(LED_PIN, HIGH);

} else {

digitalWrite(LED_PIN, LOW);

}

Serial.print("received: "); Serial.println(data);

delay(500);

}

Code can be found in RX.ino

Attachments

Step 5: MediaTek LinkIt ONE A0 Pin

We have used the A0 Analog pin of the LinkIt board. In order to understand the correct threshold to be used in order to determine a HIGH bit over the air we added a console print, which prints its value. This is also a nice tool to debug your system, and see the signal strength.

Step 6: Wrap Up

Personally, I'm a big fan of the 433MHz module. It's extremely useful for any RF communication that doesn't need the complication and load of wifi or bluetooth.

Hope you enjoyed :)

Aviv Mussali