Thread: Raven's take on the animatronic raven

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Hi boils & ghouls! I just popped in to give you a peek at my animatronic raven's progress, and a rough idea of how it's done. I finished up early today, and took the rest of the afternoon off so I had a little time to play. Pls. bear with me, as this is going to be a long winded thread due to the fact that I'm working on several different projects at the same time and splitting my time between them. Since I've been putting off a trip to the hardware store for needed supplies to finish my obelisk (I'm going tonight, I promise! ), I've put a couple of evenings in on the raven and here's where I'm at:


Probably the most physically difficult part of the build for most people, will be the servo tray. Which also serves as the backbone of the build itself, so it needs to be rather durable, but also lightweight. Aluminum is your friend here, serving both needs handily. Not to mention, it has a couple of other endearing qualities: easy to work with, and not very stressful on
tooling.


I chose to use a scrap piece of 3" x 1/8" sidewall box tubing I had laying around. You could use thinner 1/16th inch, but I really wouldn't recommend it due to the torque of the servos which may induce a twist to the frame while moving. Also, I have to note: This can all be done with relatively simple hand tools. You really don't have to have anything more than a Dremel, a few small files (jewelers files are incredibly useful here), a jigsaw, & a drill.


In point of fact, the only tool I used not on that list, was substituting a die grinder in place of the Dremel. It makes material removal a bit faster is all.





Just in case anyone thinks it's plastic...nope, aluminum. Sorry for the blurriness of the pic, I didn't see it until after I'd painted the tray. :/ Btw, instead of buying expensive etching solutions for promoting paint bond to aluminum. Simply hose down the aluminum w/ EZ-Off (or a similar) oven cleaning spray. Leave it for 15 minutes, rinse, dry, and it's ready for paint.




Servo's in place with vibration dampers.










Now I'm off to machine & attach the universal joint, and begin fabbing the servo linkage bracket.

...and just that quickly, the neck bones connected to the back bone







Instead of going the expensive route with the ServoCity U-joint, I opted for a pair of RC truck slider axles (with U-joints as seen in the photo) which ended up being 4 for the price of one of ServoCity's version. Drilled out the splines, used a length of 1/4" i.d. brakeline, then sleeved it with a small brass tube (sourced from an old broken extendable pick-up magnet) for a nice interference fit. Total cost for the neck joint, about $4.00 per, roughly. The big upside, is now I have 3 more U-joints for other neat little ideas.

Need's a little touch up on the paint, nbd.

Edit/ Touch up's are finished!

Alright, because I have to get some hardware to mount the servos (which I could've sworn I already had), we'll move on to the raven's body. I chose the Cawlin' Crow instead of the Greenhead because it already includes a weatherproof speaker built into the body, a big plus in my book. Yes, it's a slight shortcut on my part, but it also allows more versatility with mounting the raven in places where a separate speaker would be visible. Additionally, it's a pretty decent sounding speaker w/ a rear resonance chamber.



Step one: Applicable if you use an Edge Cawlin' Crow decoy like I am, then you will need to separate the beak halves (cutting off the lower half of the beak). An Exacto or scalpel is indispensable here! If you use the Greenhead Aggressive Caller decoy which has an open beak, you will only have to cut the backside away. The Cawlin' Crow on the otherhand, has a closed beak, and it will need to be manually cut away from the top half.







Step two: OFF WITH HIS HEAD!!!







Step three: Put out his eyes! 10mm translucent red with red tinted lenses are what I chose for this project because even when they are off, they look pretty scary. First things first, heat up a small piece of steel wire/piano wire/etc, and push it through the center of the eye. This serves as a guide to keep the drill bit from walking about and destroying the object of your affections. Use a 3/8" bit, and carefully center the bit on the hole you just made in the eye. 3/8" is ever so slightly smaller than 10 mm, so the LED will sit in behind the hole, leaving the rounded lens portion barely protruding. Looks very realistic imo. Drill slowly through, then trim the flashing with an Exacto or scalpel. Whichever you have handy.




Step three (Cawlin' Crow only): Drill out the pop rivets in the bottom that hold the sound module/battery pack in place and remove it. The speaker is connected via a plug that is easily accessible through the neck after you've lopped off his head. Or when you pull the sound module out, just unplug it then. I'm putting mine aside to use with another prop later on.






...and that's all for tonight folks.

Thanks Raven. High quality build. Please keep us posted.

Looks great!
Maybe some day I'll try to experiment with servos. Looks cool!

I've always wondered how this is done! Thanks

Looks great allready!!!

How are you gonna controll the servo's?

Perfect! Thanks so much for doing this. This will help all of us aspiring for this prop this year. I just picked up a drill press and some new metal drill bits. So I'm ready to start getting the parts and servos to start this bad boy. Subscribing to this thread!

For the angle aluminum was the size 2"x2" -- 3" inches in length? I think 2"x2" is the largest I can pick up at Home Depot.

Thanks for the kind comments everyone! Happy to be of service



@ Mr.Fright: I am using a Polulu Micro-Maestro, although in retrospect I would've been better served with the Mini-Maestro instead. HiRez indicated (after my order had already shipped unfortunately), that the Micro-Maestro is incapable of triggering an mp3 player board (like the Sparkfun boards) without being connected to a computer via the USB connection. For me, it's not an issue as he'll be sitting on top of my entrance columns, in which a computer will be controlling other FX. However, to be fully independent of a computer aside from initial programming duty, I would recommend the Mini-Maestro instead.




@ Jimmyzdc: No worries, the actual physical size of my servo tray is 2" H x 1.5" W x 4.25" L (5.8 cm H x 3.8 cm W x 10.8 cm L). I'd suggest for most, going a little larger than my dimensions. Mostly due to the fact that I have a lot of experience machining metal, and the aluminum being very soft (at least, in the stock that you'll find at local hardware stores. Alloy 2023, I believe) makes it rather difficult to work with, with respect to how thinly I machined the sides on mine. So, I'd add at the very minimum .25" (6.5 mm roughly) to all of those measurements for less experienced persons.


Albeit, my personal reasoning is that I would prefer to keep the price tag down as low as possible, and so I am going to much larger lengths to ensure that it is as light as I can make it (Preventing the need for high torque servos, which would hike the build cost by quite a bit). All without compromising structural integrity.


I'd recommend going to a welding fab shop to source the aluminum. They will typically have much better inventory than what is available at the home improvement stores. In which case, I'd suggest T-5056 Aluminum stock.



Hope that helps you guys out. Feel free to voice any questions you might have.

Just for information...whats the difference between the types of aluminum? Is there a chart somewhere that talks about the different types?

Thanks