Maja Drone Airframe is a very stable platform

The Maja Drone platform from Bormatec is a very stable, easy to handle and rugged platform for UAV's with a small payload (~300g in our case).

Due to the superb slow speed behavior of this platform it is also operable by inexperienced pilots.

• 0:30 takeoff
• 1:20 landing

on a gusty day.

Universal r/c camera shutter control

This is a first proof of concept for a universal camera shutter control. The goal is to turn a camera on/off as well as controlling its shutter. Both functions are controlled with one radio channel (3 position switch) from an r/c receiver. The green LED signals that the camera has been turned on and the red LED that the shutter is operated with a predefined interval.

Parts for this hack cost approx. U$ 5 so far.

Reading PPM Signal with arduino

I want to trigger additional logic in an UAV when I flip a 3 position switch on my R/C transmitter. This sketch will decode a PPM signal from an R/C receiver and will turn on two LEDs depending on switch position.

The code compiles for a Sparkfun Pro Micro 16MHz and also on an ATtiny85:

/**
 * Read PPM signal
 * 
 * Decode r/c receiver PPM servo signal and turn lights on 
 * according to servo position.
 *
 * $Id$
 */

// from which pin to read.
#define PIN_PPM   9
#define PIN_POS1 10
#define PIN_POS2 16

unsigned long duration, lastgood = 0;
int position = 0;

void setup() {
  pinMode(PIN_PPM, INPUT);
  pinMode(PIN_POS1, OUTPUT);
  pinMode(PIN_POS2, OUTPUT);
  digitalWrite(PIN_POS1, LOW);
  digitalWrite(PIN_POS2, LOW);
}

void loop() {

  // the length of the pulse (in microseconds) or 0 if no pulse 
  // started before the timeout (unsigned long)

  duration = pulseIn(PIN_PPM, HIGH, 20000); 
  if (duration == 0) {
    duration = lastgood;
  } else {
    lastgood = duration;
  }

  // map ppm values to 0, 1 and 2

  position = map(lastgood, 1000, 2000, 0, 2);

  // 0 == both off, 1 == LED1 on, LED2 off, 2 = both on 

  if (position > 0) {
    digitalWrite(PIN_POS1, HIGH);
  } else {
    digitalWrite(PIN_POS1, LOW);
  }
  if (position > 1) {
    digitalWrite(PIN_POS2, HIGH);
  } else {
    digitalWrite(PIN_POS2, LOW);
  }
}