Rebuliding of a remote control transmitter for the use with KAP

Built at: May.27.2002
Last update: Dezember 06, 2004 		      Diese Seite ist auch in Deutsch verfügbar.
To control a KAP-Rig you normaly need a three channel remote control for the funktions: ROTATE, TILT and TRIGGER. A customary four channel transmitter has two sticks to control this functions. If you leave a stick, it moves to the neutral position. That is good by controlling an model airplain or an other modell. At KAP this funktion is not good because the rig then allways moves back to the neutral position too. Rotation buttons are better in the use for KAP because the rig keeps the direction if you leave the button. Also the box of a transmitter is build for the use to control a model and is relative big in size. So I have rebuild a remote control transmitter for the use with KAP.  

   

The KAP-transmitter can be carryed arround the nack
of the KAPer. The antenna is
only a wire and hangs down.
Camera: Canon EOS D30
  At the beginning: Robbe Futaba F-14
The transmitter Robbe Futaba F-14 is a four channel transmitter with two control sticks. The price without accu and without cristal was 49,00 Euro. The four channels can be controled with two sticks. Both have a mecanical trimming for all four channels.

The transmitter Robbe Futaba F-14 with
two control sticks
Camera: Canon EOS D30

    
Opened transmitter:
The circuit of the transmitter is mounted at a big mainbord and is splitted in two parts. At the left side of the picture there is the HF-part, the real transmitter. At the right part of the mainboard there is the impulscircuit. The four controlsticks are plugged at the mainboard and can be easy disconected. Only the antenna is solderd at the board (the white wire) and must be unsolderd.		  
   

Opened transmitter with the mainboard
Camera: Canon EOS D30
The mainboard must be splitted in two parts:
Because the new transmitterbox is smaller than the Futaba F-14, the mainboard must be splitted in two parts. The two function blocks, HF- and Impulscircuit are at two places at the mainboard and only connected with three wirejumpers so the board can be splitted easy into two parts.
     

 

The connection between the two blocks on
the mainboard is made with three
wirejumpers (in the circle).
Camera: Canon EOS D30

  

The splitted mainboard.
Camera: Canon EOS D30
I have done thees changes so that the circuits can be mounted into the new, small box:
  • The two circuit bords are connected with short wire strips.
  • The cristal must be mounted at a new place and must be solderd with two short wires (see right picture).
  • I would not to have a long antenna like at the original transmitter. So I have solderd a wire at that point at what the original antenna was solderd. To protect it I have drilled some holes into the board.
  • The two black, standing capacitors must be mounted flat to reduce the high of the board (see left picture).
     

 

The two pcb-boards are connected with short wirestrips.
In the left hand corner you can see the plugs
for the four control-stics.
Camera: Canon EOS D30

  

The cristal with it´s short wires is mounted at a new place. The antenna wire is protected with drill holes.
Camera: Canon EOS D30
A substitute of the control sticks by rotation buttons and a key.
A normal poti has an angle of rotation of approx. 270 degrees. In the transmitter there only being 90 degrees in use. When pressing the trimming at the transmitter the potis are twisted mechanically. When replacing the control sticks of the original transmitter by rotating potis for the movements ROTATION and TILT of the KAP-rig or a key for the camera TRIGGERing the resistance of the potis must be copied electrically:
     

 

On the blue pcb-board there are the resistors and
trimmers to substitute the control sticks resistors.
Camera: Canon EOS D30

  

The two black buttons for the funktions ROTATION
and TILT of the rig and the red key for the
TRIGGER-function. There is also a charge jack,
the main switch and a LED.
Camera: Canon EOS D30
Substitute for the control sticks with rotation potis and a key:

Measurements at the orignal pots:
A pot of the remote control transmitter has a resistance of 5 k ohm. I have tested a value of 2 k ohm to 3 k ohm on the connections "A" and "S" at the activity of the stick. This means that only the middle area is used. By the activity of the trimming there is an additional change of only 120 ohms. (see left picture, left).

Substitute of the resistors for the funktions ROTATION and TILT of the Rig:
This values must be taken for the substitute pots. The used pot has a resistance of 1 k ohm and can be used in 270 degrees. So an equal variation of 1 k ohm like at the original is given. The rest of the 5 k ohm resistance is given via two resistors and two trimmers. (see left picture, right).

Resistors and key for the funktion TRIGGER:
For the funktion TRIGGER I used two 10 k ohm trimmers and one key. The trimmers are connected parallel so a value of 5 k ohm is given at the pins A and E. With the key I only switch between the two different values of the trimmers. One is adjusted for the servo neutralposition and one adjusted is for the servo TRIGGERposition.
     

 

At the left the original controlstick resistor.
At the right the substitute with a 270 degree pot.
Camera: Canon EOS D30

  

For the funktion TRIGGER I switch between
the two pots with the key..
Camera: Canon EOS D30
Mounting of the transmitter in the new case:
For the powersupply of the transmitter I use eight NC - Akkus of the size AA. This powerpac gives a voltage of 9,6V. The accu is at the ground of the case. To protect the accu and the transmitter I have solderd a box out of pcb-pieces. At the pcb-board I have mounted the two pcb-boards with the transmitter and the impulscircuit. In front of the case you can see the blue board with the resistors.
         
   

The eight NC-Accus at the ground
of the case for the powersupply.
Camera: Canon EOS D30

  

The pcb-board between the accu
and the transmitter board.
Camera: Canon EOS D30

  

The two boards with the transmitter (right) and the impulscircuit.
Camera: Canon EOS D30

Powersupply and operatingtime:
In the users manual of the Robbe Futaba F-14 with a 1,4 Ah accu a operating time of six hours is given. I have used 0,7 Ah cells so the time must be approx. 3 h. This is mor than enaugh for me.

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Manfred
http://KAP-Man.de

Manfred