A couple of years ago I created a Zibo 737 MCP test panel using a Teensy as my control board.  Although it worked rather good… it took several weeks to figure out the datarefs and write the code.  A couple of weeks ago I brought the sim up from the basement and thought I might work on it again. This time I decided to replace the Teensy board with SimVimCockpit and leave the wiring in place. It took me every bit of five minutes to program the Mega vs. weeks for the Teensy.

But, I had one problem; my A/T ARM switch uses a (ON)-OFF-ON switch. These switches are normally use as the A/T ARM to simulate the magnetic switch which are on the real MCPs. This prevents overriding the auto shutoff of the Auto Throttle and can still be shut off manually therefore emulates the functions of the magnetic switch.  This switch requires two pins (Momentary side for ARM and Latching side for Off).

I could not figure out anyway to use this three position (momentary/off/latching) switch for the A/P ARM switch on the MCP in SimVimCockpit.

Could you please add a variant for the (ON)-OFF-ON switch to the A/P ARM of the MCP on the Boeing 737x.
Mar 3 in Digital Inputs by

1 Answer


In SimVim you should use a 2-position switch as in real b737,  and  SimVIm parameter AT_ARM
There are 2 options:

1. Using OFF-ON  switch (with 2 fixed positions) with some mechanics modification.
The "AT_Armed"  output (used for LED) also used as inverted digital output in this case to turn on the electromagnet return mechanism or servo.

Using OFF-(ON ) switch with momentary ON position.
The "AT_Armed"  output  used as digital output in this case to HOLD the ON position by electromagnet.

See the Theo's video here and his blog.


Mar 3 by