Brian,
This project is 3 years old. The objective was to develop expertise in semi-autonomous (plane takes off and flies itself on a prescribed route and lands itself) very small fixed wing aircraft design. Although I scratch designed and built a nice-flying 48" wingspan R/C Tractor, my investment in time and affection for the result lessened my interest in using it as a mule for auto-pilot design. Accordingly, I bought a Pandora from Motion R/C and set it up as a tail-dragger - looks something like a C-185.
I used the Pandora to learn how to fly R/C, which took a lot longer than I expected - my 3500 hrs PIC in the usual GA planes had very little positive effect on this. Pandora was a good choice, easily repaired with hot glue after all but the most severe crashes. I'm on my third, btw.
I designed, using EAGLE, a PCB motherboard to hold the Teensy 3.2, the voltage regulator, the MicroSD adapter, and the Molex jacks to connect to the Clock, the GPS, the Accelerometers, compass, gyros, and pressure sensor, as well as the external power connector, a serial output to connect an external output display, a switch to turn power on/off.
All of this was installed in the cabin roof of the Pandora, see photo.
View attachment cabin-roof.pdf
The hardware in the photos goes back to the beginning. The idea was to collect flight data on an "understood" airframe flying at the local R/C field.
It has worked well and I now have gigs of flight data as per earlier post. I've also realized that developing flight control software in simulation might consume fewer airframes. I wanted to model my own plane in X-Plane and so needed the control responses hence the need for S-Bus channel capture which is why we're talking about this.
Once I get through this (simulation development) and the resulting device can fly the Pandora smoothly and accurately, I'll set out to reduce airframe to smallest thing I can make work. I have 2 3D printers (used mostly for tooling and brackets), a cnc mill, cnc router, lathe, several bench saws, drill press, re-flow oven, oscilloscopes with support equipment and most (but not all) of the other stuff one accumulates over a lifetime of doing things like this.
I had intended to make my own electronic package for the small planes which would be T-Shaped in section with the top containing the devices which need to be horizontal and the leg, the micro-processor, the voltage regulator, the gps and the clock. My thought was to build this up from the chips, not use modules. I also expected that it would be too small for me tomake myself so I'd do the boards in Eagle and send them out to a job shop. I don't know if this stage will have any recording. One can buy very small 900 mHz receivers now. The ones with simply an S-Bus output are very compact and offer the opportunity to locate the receiver for best antenna reception and drive the servos from an sbus-converter located to reduce runs to servos.
I have a long way to go and don't really know when I'm going to get to later stages. I'm 76 and have plenty (but not enough) time to pursues this.
One thing I have discovered is beating yourself to death on one design element wastes time. Far better to have 4 or 5 aspects of project going at the same time, this way you can work on something else if you stall on one thing. And then, Voila!, at 3 in the morning you'll realize a solution to whatever had you stuck,but in the meantime you progressed other parts of project. So I'll have some airframe thing going, along with tooling improvements, maybe upgrading pcb's, and then some code.
And yes, I know that other guys are doing this ad probably more effectively than I am, but this doesn't bother me. This is for fun, not commercial. A lifetime spent doing projects for other people has left me with a bad case of "customer avoidance" I gave at the office. No More.
best,
John ferguson