Replacing the AV-50000A

[j4cbo]

I've been considering removing the AV-50000A in my RV-12 and replacing it with a custom, more targeted distribution board. Why?

1. Simpler wiring means easier troubleshooting
2. Bypassing the "box" for audio and sensor wires means less risk of noise/interference
3. Most importantly, because I think it would be fun

What's wrong with the AV-50000A? Well, it tries to be a "one-stop shop" central box for everything, which is great in theory. In practice, as the avionics used in the RV-12 have evolved, some extra connections need to be introduced that weren't foreseen, so the harnesses again become complicated (e.g. rerouting the trim switch to the SV-AP-PANEL). Meanwhile, some functionality in the AV-50000A (like trim speed control and audio mixing) becomes unused. The idea I've been working on is to replace the AV-50000A with a custom board that exactly meets the needs of my aircraft. And as it turns out, Van's took a similar approach in the 912iS - the Dynon SV-NET bus, audio signals, and firewall-forward instruments all route through the AV-50000A in the RV-12, but they don't go via the AV-60000 in the RV-12iS.

I'm currently planning to keep the existing Van's ignition and switch modules, since they do the job just fine, and design a new board to sit in the middle of everything.

Here's what I've got so far. The board is pretty much complete; the harness documentation definitely isn't (I'm not used to specifying wiring harnesses) but it'll get there. For most "why did you do it this way" questions, the answer is "because I have those parts already": the optocoupler for the stall beep, ATtiny24 microcontroller, tiny 0402 passives, etc. Your mileage may vary. The connectors are Molex Micro-Fit 3.0. Board dimensions are 75mm x 98mm.

Thoughts?

[Mich48041]

I admire your skills. What software do you use for the schematic and board?
One reason not to make your own board is that some day you will sell the plane.
Then when the new owner tries to get someone to repair the electrical system,
nobody will know how. On the other hand, if you don't design and install your
own system, you will miss out on a lot of fun. Go for it!

[j4cbo]

I use EAGLE. It's worked well for me but it's not what I'd recommend - Autodesk bought the company that made it and now it's only available as a subscription

[DaleB]

Originally Posted by j4cbo

I use EAGLE. It's worked well for me but it's not what I'd recommend - Autodesk bought the company that made it and now it's only available as a subscription

I have what I think is the last version of Eagle that was released before Autodesk bought them (7.7.0). I'll never give it up. KiCAD has also gotten pretty good.

[rcarsey]

Can always give CircuitMaker a try!

[backcountry]

I for one had to remove all the com/audio from the box due to noise.

As time goes on I feel there will be many issues developing due to numerous connections in that box and troubleshooting will be difficult because everything goes to it.