Futaba 6EXA - Interface Output?

[PGD]

I have built the 680ohm/4.7vz interface for my Futaba 6EXA.

I am getting no response on the calibration bars. The system works great with the keyboard and the joysick.

The output across pin 18 and 10 is a positive going pulse of 3.5 volts amplitude, and varying in pulse width according to the settings of the sticks.

The question is, is 3.5 volts enough to operate the port?

THANKS for any input. Pete

[Eric Brouwer]

The 3.5V output might not work stable on all PC's. Some ports work correct with a voltage level as low as 2.5V, but others only above 4.5V

Remember to also ensure that the parallel port is set up as ECP/EPP in the BIOS.

Note that this circuit does not work on all Windows versions. It will not work with Win2000/XP. I do not know about WinME.

Try using this circuit. It might help.

100K
----------/\/\/\---------------------- Pin 16
| 10K |
| ----/\/\/\--
| |
| |--------------- Pin 10
| c|
| 2K2 b / 2N2222
PPM ------------/\/\/\---------|
e \
|
Gnd --------------------------------------------- Pin 18

The 100K resistor is used to cater for JR transmitters, with a PPM signal as low as 0.7V.

Hope this helps

[PGD]

Thanks Eric,

I am now flying glitch free.

The 3.7 volts I quoted was open circuit. When I checked it connected to the port I only had 0.7 volts.

I built your circuit useing a BC109 transistor, that I had at hand, and it works great.

Thanks again, Pete

[Eric Brouwer]

Glad I could help.