Credit:  The seminal work was done by C. Brent Dane in his GOSLOW design.  The idea was resurrected by John Hawkins and now it presents us an opportunity to implement it in 12F675 form.

The Problem: 

Transmitters generally have one of three methods to trigger flaps: 1. Toggle switch UP/DOWN 2. Toggle Switch UP/MIDDLE/DOWN 3. Twisting potentiometer 0% to 100 %

In cases 1 and 2 when the command is given, the flap servo moves very quickly and the result is that the aircraft pitches up or down.   The same pitching  phenomenon occurs when the flaps are pulled up too quickly.  Regardless, as Mr. Dane points out, if the flaps can be made to move slowly in either directly , the pitching does not occur.

The Solution: 

We know that the Pulse Wave Modulation (PMW) on the receiver output will be 1millisecond, 1.5 milliseconds or 2 milliseconds.  So, the trick is to turn the servo into a stepper motor and have it cycle through small increments slowly and smoothly.

Timing: 

Some folks might want to be able to vary the timing of the movement of the flaps.  In general terms, there are three ways to do this.

        Method 1:  Hard code the values as per the example in the sidebar.

Method 2:  Use jumpers to select three different speeds - fast, medium and slow.

Method 3:  Use a jumper to enter programming mode.  Using an LED that flashes ON/OFF once per second, time the period that the jumper is in place and use that value as the speed controller.

 

The example in the sidebar was written by CatsEyes and modified by Ironsides.

The receiver signal is received on GP3.

The flap servo gets its marching orders from GP2

 

 

A ProBasic Pro version is posted as PBP Slow Flaps on the side bar.  The zip file includes the PHP and hex files.

 

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Last modified: March 18, 2004