Step 6: Servo reversing

Sometimes it's necessary to have a servo that turns in a direction opposite of the other servos you're using. I needed to do this for one of the servos that will raise and lower the "fans" on the side of the helmet since that servo is flipped around. If I didn't do this then one fan would rotate upward while the other one rotated downward.

There are two ways to reverse a servo's rotation: buy a special connecting cable or modify the wiring in the servo. I chose to modify the wiring. These instructons apply to the Hitec HS 300 servo but most servos are similar in construction.

1- Remove the screw holding the servo wheel/bellcrank
2- Remove the screws holding the servo case together
3- Remove the bottom portion of the servo case, exposing the drive motor
4- Reverse the position of the two motor wires
5- Remove top of servo case, paying attention to the gears and their positioning
6- Remove the retaining nut for the potentiometer
7- Remove circuit board from bottom of servo
8- Remove potentiometer
9- There are three wires connected to the potentiometer- swap the two end wires. Do not touch the center wire
10- Reassemble servo

That's it!
<p>Hi this looks great but would be nice if you din't have to pay for the PDF.</p>
I am working at animatronic animal factory in China , we do another way to that, if you want to made it in your house , you can check our factory picture and website <br>www.amodinosaur.com <br>https://www.flickr.com/photos/amodinosaurio <br>
<p>Hi Honus, I'm very new to this website so I hope I'm posting this in the right place. I have never worked with any kind of animatronics before but I am hoping to make a costume for a convention which would require very basic animatronic features (Mainly eyelids that are able to shift from half open to completely open, lights inside the eyes ((that are constantly on but can be turned off if not in costume)) and a speaker function that plays one noise on command, presumably both triggered with a button). I was wondering if you would be able to give me any advice/instructions with this? Thankyou very much. </p>
Hi there! What you want to do shouldn't be too difficult. The first thing to do would be to have a look here-<br>http://www.instructables.com/id/Arduino-animatronics-make-your-awesome-costumes-m/<br><br>That will get you started on how to connect a servo to make your eyelids move as well as how to connect some LEDs for lighting them. <br><br>For sound I'd use this board- https://www.adafruit.com/product/2210<br><br>It's super easy to use and you can use a single button to trigger your sound effect.
<p>Hi ! Thanks for the clear instructions. I am building a tool where I use servos and am looking for crank/ clevis mechanisms similar to the one you have used. Where can I get them from? and how do you fix it to the servo arms? I currently use a Tower Pro SG92R servo</p>
Check out Servocity. They sell all kinds of servo hardware and linkage parts. <br><br>http://www.servocity.com
hey makingthings.com site is down as of this posting just to let u know. in fire fox i get (problem loading page)..........
hi Honus,<br>I have a project on hand and would like to discuss with you, can you call me (Harry) at 340-513-1995.
where did you get that hours guard helmet where plese tell i need to make one to go with my jafa armor on my work bench
That's pic from the show- I still haven't made mine yet but I'm working on it. It's probably going to be primarily cardboard to keep the weight and cost down. The original movie helmets were fiberglass and I do know of one guy that made a run of Anubis/Horus helmets and they were big bucks- over $1000.00 as they were a tremendous amount of work to make.
ohh sorry looked like you in costume should thought about that
Hey I had an idea for an animatronic wolf. Any sggestions on how to make this?
There are a huge number of variables here- it depends on how complicated you want to make it. Is it just an animatronic or a costume? Do a search for wolf costume or animatronc wolf and go from there.
Finally got video of my Horus costume.<br> <br> See the video over at YouTube:<br> <a href="http://www.youtube.com/watch?v=pKf9VMGt540">http://www.youtube.com/watch?v=pKf9VMGt540</a><br>
That is awsome!! I really need to get working on mine. I redesigned the mechanism a bit and of course it's now Arduino controlled.
Great work! I'm really glad to find it! spidesk.ru
is there a cheep (probaly not but cheap as in under &pound;30/$30 controller kits with 8 flex sensors??? thanks im just about to make a few prothsthetics of predator and figured id use an animatronic head :) (never made 1 before)
The best inexpensive controller out there in my opinion is the Arduino. There's a wide variety of models available and most are $30 or less. I don't know of any flex sensor kits- the sensors themselves cost about $13 each.<br><br>The Arduino Nano and Fio both have eight analog inputs and the Mega has even more but it's much more expensive. The Fio is the only Arduino that has eight analog inputs that costs under $30.<br><br>There's a spreadsheet here that shows all the different Arduino versions-<br>http://jmsarduino.blogspot.com/2009/03/comprehensive-arduino-compatible.html<br><br>I've actually already designed an animatronic Predator head (I haven't yet built it) so if you need help with it let me know. I'll have my Arduino animatronics tutorial up soon- I'm just putting the finishing touches on all the code examples and organizing all the photos, etc. It's going to be a fun one!
thanks I have never even looked into animatronics so I'll probably start with an arm lol but still can at least try :).
Can you add more than two flex sensors? If yes, how?
The board supports up to eight analog inputs so you can have up to eight bend sensors. You connect them just like the other two regarding power and then put the sensor's output signal into each additional analog input pin. In order to use them you would need to write your own firmware for the controller, which I haven't done.<br><br>I am almost finished writing all the code for my Arduino animatronics tutorial and I've designed a board that will allow you to connect six bend sensors to six servos (amongst other things) so stay tuned!
One question: the firmware is some kind of code concerning the MAKE controller?
The firmware is the code that tells the controller what to do.
Aha, can you find the controller somewhere else than the Making Things site? I'm asking because they are out of stock :(
Hey, how's the Horus costume going? I heard you were swamped with projects. I picked up the original Stargate at Walmart for $5, and was wondering, how the hell are you gonna make the mask shrink up into the back? :p
It's going well- I'm redesigning the electronics right now. The mask doesn't shrink up up the back. The only thins that move are the head and the fans on the side of the helmet. The eyes light up as well.
Haha, I was just joking about the mask shrinking up in the back. I have a question for the costume, are you going to do the Movie or TV series armor considering the cold weather?
Probably the TV series- unless I get in REALLY good shape!
Sorry for the constant questions but, how are you going to see out of this costume?
There's a mesh screen on the upper section right below the head- that's how they did it on the TV show helmets.
Thanks! That'll help me with the scaling of the pepakura file.
I had this idea to make an animatronic Horus costume from Stargate... so I started searching for reference material - I couldn't believe it when I found this site. Ordered a MAKE Controller within 10 minutes of reading about it. One problem is that the latest firmware does not have POLY mode, so you would need older firmware for these instructions to work. I've started writing my own controller code...so far so good.
That's a bummer about the firmware issue. Lately I've been using the Arduino a lot- it's nowhere near as powerful but it moves servos around just fine (I'm currently using it on my Predator project) and they're dirt cheap.<br/><br/>As for some help with the Horus you may want to have a look here:<br/><a rel="nofollow" href="http://skipspepakuracostumes.blogspot.com/2008_06_01_archive.html">http://skipspepakuracostumes.blogspot.com/2008_06_01_archive.html</a><br/><br/>This guy does unbelievable work!<br/>
I did finish my Horus costume for Easter 2009, had issues with the flex sensors so switched to an old PC analogue joystick mounted in the head with mouth/chin control.<br /> <br /> <span><a href="http://www.facebook.com/photo.php?pid=5355459&amp;l=3d1b1a886a&amp;id=642109656" rel="nofollow">http://www.facebook.com/photo.php?pid=5355459&amp;l=3d1b1a886a&amp;id=642109656</a><br /> <br /> It didn't win any prizes, but it was popular at the Swancon Masquerade.<br /> <br /> About a week later it almost got destroyed when a car crashed into our house.<br /> </span><br /> My latest project was an flexing tongue for another costume using an Arduino, cheaper, smaller and less power hungry.<br /> <br /> Thanks for a great Instructable.<br />
That is freaking fantastic! Did you make it so the fans moves up and down? I&nbsp;figured I'd have to make mine using Pepakura but I&nbsp;still haven't got around to modeling it since I've been so busy with other projects.<br /> <br /> Bend sensors can get pretty noisy, especially when you have to use them with long wires. I've redesigned my Horus control system to be wireless using the Arduino platform.<br />
<p>how much should the total price be around.</p>
For what? It depends on what you're trying to do...<br /> <br /> Servos can be purchased for around $10 or so unless you need a servo that is very fast or strong. The MAKE&nbsp;controller with application board costs $109. Lately I've been using the Arduino platform, which is much easier (for me) to use and is significantly less expensive. When I&nbsp;finish the Stargate helmet project that is what I'll be using.<br /> <br /> <br />
I read that the i-cybie robot dog was supposed to have 16 servos on board, so I was a little disappointed when I opened it up and found this cheapo elektrical motors you find in every other toy. I got one that had short circuited, and wanted to try to bring it back to life with an arduino as a servo controller, but i ended up just connecting it up to a toy keyboard to be able to trigger some kind of movement. Can be checked out here http://pappmaskin.no/2009/11/frankendog-diy-animatronics/<br />
Sorry, I just have another question. You mentioned that as the wires to the flex sensors get longer, there is an increase in noise and therefore a decrease in the accuracy of the sensors. How long were the wires which ran from your hand to the MAKE controller? and approximately how long would you suggest I allow the wires to be?<br/>Thanks =)<br/>
The wires I used were probably around four feet long and I didn't have any problems.
I'd love an arduino animatronics tutorial. I've used an arduino to make a servo move before, but the subtleties of building something like say, an eye mech, are a mystery to me. I'd love to be able to cheaply throw together some potentiometer or wiimote controlled eyes (left right, up down, maybe even blink) with an arduino, a few servos, and some chunks of shapelock.
I'm working on it- it's still going to be a bit.... A good book to check out is No Strings Attached. It's the story of the Henson Creature Shop- they were the guys that really invented the animatronic character. The Stan Winston Studio book is also excellent. Physical Computing by Tom Igoe is a must have. There is surprisingly little information available about animatronics. And not only can you make eyes blink but you can also make the pupil dilate- and it's easier than you think.
Wow! I'll check out those books...
Very nice! I am currently working on an animatronic mechanical hand, each finger being controlled by its corresponding finger on my hand. I am using the same sensors that you used (SpectraSymbols 4.5" flex sensors are the only ones out there I could find anyways, I got mine from Sparkfun.com), and will be utilizing them through a glove setup, as you have done. @Weevil, I will be using the Roboduino, which is a robot-oriented version of the Arduino. I might (if time allows) document my results and create an instructable on it. @Honus, is there any optimal value for the resistor used for the flex sensor? My friend suggested I use 14k.
I used a 10K resistor and that seemed to work pretty well.
Ok, thanks.
I thought ur never supposed to directly wire resistors to motors?
I see resistors wired to DC motors all the time.
is there a way to make the MAKE controller?

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Bio: I'm a former bicycle industry designer turned professional jeweler. I like working with my hands and am happiest when I'm in the shop ... More »
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