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aeropunk

Active Member
Just curious if anyone else has messed around with an idea like this? I thought it might be a neat way to avoid those push/pull cables, and also maybe to have some sort of automated cabin temperature control.



I'm concerned about issues of heat near the nylon servo, and also failure modes and some sort of fail-closed mechanism. Haven't decided to go this way yet, but I thought I'd see if I could get it to work.

Here's a video of the servo in action: http://youtu.be/vV5_2b3UdB0

Any thoughts?
 
Great idea

I think if you were to shield the servo from heat, i.e. a small aluminum enclosure acting as a heat sink/barrier or with ram air from a 1 inch scat tube should do the trick passively. a spring small enough for the actuator to overcome to open the box should work. Let us know what works out. I agree that the cables can be a pain in effective routing to allow smooth operation.
 
servo

Brian, Can the servo be slowed down a bit ? It is sorta of an on/off switch at that speed. I use one on my oil shutter control. Two years, 220 hrs. and works fine. Had one on same heat control but was not as nice of servo and wires kept coming out of the servo. Your servo choice looks more robust. Ron
 
Related question

Brian,
I haven't purchased a heat box yet. Could you tell me - did you get this one from Van's? Part number?

Thanks,
Mark
 
aeropunk said:
Just curious if anyone else has messed around with an idea like this?
Any thoughts?
Click to expand...

Oh sheesh... stuff like this may call for a new Forum category. Something like "Open Source Gizmos". That looks like an Arduino pro-mini running that servo which anyone here, that has programmed their EFIS, could do in a weekend.

Sensors, servos, robotics, camera gimbals on wingtips... is all quite prevalent in the R/C world. Surprised to not see it more in full scale EA.

I have tons of ideas with this kind of stuff but, frankly, don't want the liability or the 100% support that comes with trying to make money from it. That's the beauty of what defines "open source".

So let's go with some ideas:

1. APRS - This could be made cheaper than the $200+ options out there. Plus you could choose to encrypt your track for "your/family eyes only".

2. Accelerometer ICs and break-out boards are way cheap now. Why not have one in every flying surface wing-tip to measure trends on vibration, flexing, et al. A little more involved if you want to fuse the data from each sensor, real time, but post flight processing could fuse data with a simple spreadsheet.

3. Temperature and airflow maps under the cowling. Again, the sensors for all these things are so cheap now.

That's just a few and obviously the ideas need to remain non-flight critical. Bring on the ideas...

Disclaimer: This is coming a 30+ year,in the industry, microcontroller/data acquisition geek. I'm expecting mostly sigh's and eye-ball rolling. :)
 
What heat issue? The servo would be on the cabin side of the firewall.
 
enielsen said:
1. APRS - ... Plus you could choose to encrypt your track for "your/family eyes only".
Click to expand...

That would be a violation of FCC rules (97.113-a-4)

?messages encoded for the purpose of obscuring their meaning? are prohibited (with exceptions for space control, radio control of model aircraft, and emergencies)

Paige
 
Thanks for the feedback, everyone. This is great stuff.

@868RM: Ron, the servo can be slowed down (it actually is, a little), and also stopped at intermediate positions between open and closed. I haven't worked out the logic of how an automated controller might work -- would it make sense to have a half-open position, or just modulate the door open and closed as the cabin temp fluctuates?

@aerhed: My concern exactly. The "best" option might be a manual emer-close pull cable, which sort of makes this whole concept moot.

@spark68: That is the Van's VENT TG-10 Firewall Mounted "Warm" Air Selector/Bypass Box. Came with the FWF Kit.

@rleffler: That's a fine-looking linear actuator, and not really overly-expensive when you consider the price of a high-end, metal gear hobby servo these days. I'd just want to control it with something other than their controller board.

@enielsen: Couldn't agree more regarding the need for a "gizmos" category. Frankly, with all the geeks I suspect are out there building RVs, I'm surprised we don't see more of this stuff. I love the ideas of the accelerometers mounted around the aircraft structure and the cowling heat/airflow mapping sensors. I attended Sonja Englert's "Engine Cooling" talk at OSH, and so many of the "cooling mods" you see out on the flightline just don't make sense from either a drag-reduction or engine-cooling standpoint. If I took anything away from that talk, it's that you can't just eyeball it -- you need the data.

By the way, that is an Arduino Pro Mini doing the heavy lifting, with custom code on the board and a Python script on my laptop talking to the Arduino; it's all on GitHub if anyone wants it.
 
PaigeHoffart said:
That would be a violation of FCC rules (97.113-a-4)

?messages encoded for the purpose of obscuring their meaning? are prohibited (with exceptions for space control, radio control of model aircraft, and emergencies)

Paige
Click to expand...


oops... perhaps "encrypt" wasn't the right word. ;) There are ways to make APRS private. Despite that, even a "standard" one could be made for under $80 if not cheaper.
 
aeropunk said:
Thanks for the feedback, everyone. This is great stuff.

By the way, that is an Arduino Pro Mini doing the heavy lifting, with custom code on the board and a Python script on my laptop talking to the Arduino; it's all on GitHub if anyone wants it.
Click to expand...

Sweet! I recently cooked my own pro-mini with built in USB for some friends. Less than $8! Had to test the home made pick-and-place and new oven. It's amazing how cheap this stuff is getting now.
 
enielsen said:
I recently cooked my own pro-mini with built in USB for some friends. Less than $8! Had to test the home made pick-and-place and new oven.
Click to expand...

DIY Pro Mini? Home-made pick-n-place? Reflow oven? I'd love more details of all that if you don't mind sharing! (Maybe even Eagle files for the Pro Mini?) </geekout>
 
aeropunk said:
DIY Pro Mini? Home-made pick-n-place? Reflow oven? I'd love more details of all that if you don't mind sharing! (Maybe even Eagle files for the Pro Mini?) </geekout>
Click to expand...

Sure. I can get you started with some stuff. I've been meaning to consolidate all this stuff onto a website but it's been the "Painter on the block syndrome". So busy working on others that I haven't been able to "paint my own house". Even more embarrassing is that I don't even have a photobucket type of account to post pics here. I figured I'd get to that once I actually started building an RV... hopefully in the spring.

The Pick and place was based upon this design but with my own mods to make it simpler with a shorter BOM. It works great down to 605 size components. I've done 402 by hand but soon learned I am not of brain surgeon dexterity:

http://vpapanik.blogspot.com/2012/11/low-budget-manual-pick-place.html

The vacuum pump is available on ebay and I wired in a footswitch:

http://www.ebay.com/itm/New-QS-2008-Pick-and-Place-Vacuum-Pen-Suction-pen-for-SMT-SMD-/131151651303?pt=LH_DefaultDomain_0&hash=item1e893f61e7



As far as circuit boards from your eagle files... can't beat these guys:
http://www.oshpark.com


I wimped out and bought a PID controller kit for the toaster oven. Sure, could of made that too but had so many other projects waiting to be cooked. It would be like building your own lycoming... at some point you have to pick your battles whether you can do them or not. I couldn't find the same controller on eBay but there are others. Don't spend more than $80. The key to the toaster oven is to find an infrared one with 4 heating elements.. 2 on top 2 on the bottom.

I used to cook boards on a pancake skillet. My new arrangement has yet to skunk a board.

PM me your email for the eagle files. </geekend>
 
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