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DIY Autopilot/COM panel project

PostPosted: Wed Dec 30, 2020 1:18 pm
by BradG
Problem: Transitioning from flying controls to a mouse in order to make certain inputs is challenging and breaks the "immersive experience" of the sim. Furthermore, getting to the mouse, moving the cursor to the appropriate cockpit control, and making the input can take long enough to cause me to get behind the aircraft, can result in call-outs from ATC due to the amount of time it can take for a request to turn to a specific heading, begin a descent, or can cause other distraction-related problems such as failing to note crossing a localizer course, etc.

Goal: Create a panel to give me quick access to cockpit controls. Gain experience with the Arduino - something I have been wanting to do for some time. Develop an understanding of how one uses X-Plane datarefs to interface with physical devices. Create one panel that works with the Cherokee 140, the Beachcraft Baron, the Avanti II, the JROLLON CRJ-200 and the Zibo 738.

Method: First create a prototype panel that is inexpensive, easy to change as I correct errors, reorder switches, and learn specifically how different autopilot commands interact with different aircraft. Later, after having used the prototype panel for some time, be able to re-use all of the components to create a permanent panel that is more professional looking, but much more difficult to change.

Since I was trying to create a panel that works with a number of aircraft, I was not specifically looking to recreate the look and feel of any specific aircraft. Also, for any given aircraft there would be functions that did not apply to that aircraft (for example, no VNAV or LNAV on a Baron BE58). This meant that I had the freedom to lay out the controls in any way that I wanted, but it also meant that I could not benefit from the years and thousands of hours that are put into the ergonomic design of the Zibo 738 panel, for example.

In the end, I decided to start with the JROLLON CRJ-200, and then add/adapt as required from there. This approach worked very well, and the only thing I decided to add so far that was not on the original panel was a Glideslope LED. (I also added the Glideslope mode switch, but as of now, it is not connected.)

Specifics of the prototype: I began the project by getting an Arduno Mega, grabbing a few LEDs and switches from my shop, and starting by picking one or two representative commands to see if I could get them to work with SimVim. Specifically I started with the NAV command button and the NAV On LED. I used the Baron because, sitting on the ground, I could turn on the AP, and then press the physical button to check that X-Plane reacted and that the LED lit up. Once I verified the basic connectivity and methodology of using SimVim, I moved on to a simple verification of rotary encoders and BCD switches. At that point I knew that all of the components would work and I started building the prototype.

For the physical panel, I glued some foam core art board to a heavy block of wood and attached some non-skid feet. Someone over on the Discord SimHardware channel mentioned this, and I really liked the idea. The foam core is sturdy enough to serve as a panel for switches and controls, easy to drill, cheap, and if you don't like your first layout, you can just throw it away and make another layout. I hot-glued some wood blocks to the base to secure my proto-board.

For wiring, I used a technique called wirewrap. If you are not familiar with it, basically you use a special 30 AWG kynar-insulated wire, and a wire-wrap tool. You strip the wire, insert it into the end of the tool, put the tool over the end of a header pin, and give it a spin. This wraps the wire tightly around the pin, without the need of solder. If you need to remove the wire, you simply use the other end of the tool to unwrap the wire and slide it off of the header pin. I tried to minimize soldering, not because I don't like solder, but because I liked the reversable aspect of wirewrap. Wirewrapping is also very fast once you get the hang of it. Also, the point-to-point wirewrap style I used is messy, but it allows me to quickly trace a wire from a switch to a pin on the Arduino and change it if I need to. Simple, fast, reversable. Just not pretty.

Re: DIY Autopilot/COM panel project

PostPosted: Wed Dec 30, 2020 1:25 pm
by BradG
IMG_6631.png (1.48 MiB) Viewed 136 times

Re: DIY Autopilot/COM panel project

PostPosted: Wed Dec 30, 2020 1:27 pm
by BradG
IMG_6632.png (1.24 MiB) Viewed 136 times