Thursday, August 1, 2013

Adafruit's Simple RF receiver, Testing on an Arduino

I just picked up Adafruit's Simple RF receiver right now I was testing the Momentary type (M4) Which means that while you press the keypad button the corresponding pin on the receiver goes high. I am hoping the next time I order something from them I remember to get the latching one instead because that is what I really need. Anyway since I don't have a project for this one in mind I just wanted to do some testing... so I just plugged it directly into my Arduino( avoiding the Serial pins since I needed those to display the pin states) This is the only way I could fit it on the board without putting it on a bread board. (quick and dirty!)

The VT pin isn't of to much concern for me right now so it just tucks in between the two pin banks :)

Check out the code below. This is great but if I don't want to constantly poll for buttons I may miss one. So my intention is to order a latching version, when you press the button on the keypad the pin goes high and stays high until you press it again. My thought is that if I am powering the receiver from the arduino then I can read it maybe once a second or even less often then when a high state is detected then I can simple "reboot" the receiver by dropping the +5v pin to ground. So until I get one in I will hope it resets back to ground on all the signal pins like I need

Adafruit's Simple RF Receiver example                                  
Author: Chris Crumpacker                               
Date: August 2013 

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
Lesser General Public License for more details.
Sketch Notes: This is set as if you put the reciever directly
onto an arduino with gnd in pin 2 and the VT pin in the 
gap between the pin banks.

#define GROUNDPIN  2
#define POWERPIN   3

// Arduino Pin Numbers
int signalPin[4] = { 4, 5, 6, 7 };
// Reciever Pin Names
const char* pinName[] = { "D3", "D2", "D1", "D0" };
// Keyfob Pin Names
const char* buttonName[] = { "D", "C", "B", "A" };

int lastSignalState[] = { 0, 0, 0, 0 };
int signalState = 0;
float onTime = 0.00;

void setup() {
  // Set the ground pin to a Low output
  digitalWrite(GROUNDPIN, LOW);
  // Set the +5v pin to a High output
  digitalWrite(POWERPIN, HIGH);
  // Setting the signal pins as inputs
  for (int i = 0; i < 4; i++) {
    pinMode(signalPin[i], INPUT);
  // Starting the serial interface

void loop(){
  // For each of the 4 pins we loop thru and check the state.
  for (int i = 0; i < 4; i++) {
    // Read the current pin
    signalState = digitalRead(signalPin[i]);
    if (signalState != lastSignalState[i]) {
      // if the state has changed...
      if (signalState == HIGH) {
        // ...and the current state is HIGH...
        Serial.print("Receiver Pin: ");
        Serial.print("Keyfob Button: ");
        Serial.println("Switched ON");
        onTime = millis();
      else {
        // ...and the current State is LOW...
        Serial.print("Receiver Pin: ");
        Serial.print("Keyfob Button: ");
        Serial.print("Switched OFF after ");
        Serial.print(((millis() - onTime) / 1000.00));
        Serial.println(" seconds");
    // save the current state to the last state array
    lastSignalState[i] = signalState;


  1. Thank you so much this great short and easy tutorial was so helpful i was able to use my receiver!