How to Purchase Servos

I am an evil genius and am hoping to make a small army of Arduino driven robots to aid me in my eventual domination of the world. But before that happens I need some servos, and after taking a quick look at some different sites selling them, I have no idea what kind of servos I am looking for or what I need.

In short I am new to the Arduino scene and don't know anything about servos. I need something that can drive small lightweight wheeled robots and can also do things like operate latches. If I need to buy two different types of servos, that is fine. My first big servo project is to make a robot that seeks out walls and runs into them.

Ebay, Ebay, Ebay.. from China on the cheap. Look for R/C hobby servos. You can find real deals on things like "9gram hobby r/c servos" at like ten of 'em for twenty bucks shipped.. just going to have to wait as much as 3 weeks for stuff to arrive.

R/C hobby stuff is one of the best sources, as they are usually designed to run at low voltage off batteries... I'm currently fiddling with a R/C car I got at Walmart for $7. For that $7, I've got a full rolling platform, steering (servos), the whole thing.. and can even control via the very basic (4 switches.. forward, back, left, right) remote from up to 75 feet, according to the box.. begs for a couple of transistors and Arduino control.

Other than that-- Printers. Old printers have some GREAT motors, as do scanners. For low-duty, you can even rip apart floppy drives for a couple of servos, encoders, and other fun things.

Dumpster Dive and Ebay from China.... gonna be your best sources...

Makes me wish I had never gotten rid of all those remote control cars and that RAD robot I had when I was a kid. I spent a lot of money on those things when I was younger, RAD's servos even had clutches built in so they would not kill themselves when pushed too hard, it even had some sort of data jack on the back of it. That and now that I think about it, the ol' Armatron sitting in my parents garage attic would defiantly be worth taking apart.

Gah! All those toys were gold mines that I just gave away!

Heh, well at least getting into the Arduino stuff has actually got me pulling things I tossed in boxes on shelves in the basement "to be fiddled with eventually" and actually DOING some things with them. I'd come across something interesting, pull out the cute bits and shelf them, and toss the carcasses... did for years, as many here probably do. It really adds up fast, so only keep the interesting parts, large carcasses anger spouses. Use a couple of Rubbermaid totes or whatever and just shelf em.

I've got a medium tote that's just wall warts and power supplies. Probably have a half dozen solid 5v and 12v regulated power supplies in there, a couple of DC-DC converters, and a couple of Nicad camcorder batteries in there too. Another is motors and assemblies, probably have twenty small servos and steppers as well as a bunch of toy DC motors. I have a fishing tackle box for miscellaneous small components.

I rarely spec any of it until I pull out something and want to use it. Sometimes I don't bother reading up if I've got a few of something and I'd rather burn it up than read... operating out of what are essentially trash bins makes epic failures easy on the wallet... often I have no idea how to use something when I shelf it (I've been gazing at a high-res single-pixel-wide CCD I "liberated" from a business card scanner.. still not shelved, so it's one that keeps tickling the fiddle itch. I've got a couple of old cell phones I may strip for their nice little displays.

The point is that this hobby is going to turn you into an electronics packrat probably, if you aren't one already. If you can, get in front of it and try to get some cool stuff to play with...Just don't go too crazy or the spouse tends to get a bit flakey.

Below are some inexpensive servos inside the US with free shipping.

I'm currently fiddling with a R/C car I got at Walmart for $7. For that $7, I've got a full rolling platform, steering (servos), the whole thing..

Do those cars actually have servos for steering? If so, that is a pretty interesting deal. I know some smaller RC cars use electromagnets for steering.

That and now that I think about it, the ol' Armatron sitting in my parents garage attic would defiantly be worth taking apart.

Whatever you do - don't do this! The Armatron has become a "collector's item" robot; you take it apart (and can't get it back together again), you might be looking at wasting what is sure to become worth more than $100.00 in a few years. Right now, the price is fluctuating, but most seem to be hovering around $50.00, depending on the condition (if it has all its parts, stickers, box, styrofoam).

Also - if that Armatron has everything (and I mean everything), and it is the Tomy branded version - let's just say you don't find those around any more. The Radio Shack version is ubiquitous, and recent re-make releases (yes, they did remake it and release it - but it was hideous looking) haven't harmed the value much, since the re-releases look nothing like the original Armatron (just body styling, more than anything).

So - if it is in any good shape at all - don't take it apart!

With that said - if you get your hands on one that is in "bad shape", your best bet (if you don't want to sell it for whatever you can get, or part it out to rebuilders/repairers) is to re-work it so that you can interface it with the Arduino and control it via your computer (or standalone with the Arduino).

Back in the 1980s, there were an absolute ton of articles on how to interface your Armatron with a computer. I don't know if I have them all, but I do know I have a good amount of them. If you are interested in taking this route (which is a good way to preserve an "abused" Armatron and give it new life) - check out some articles on my website about it, starting here:

Follow the reference articles at the bottom to see other archives (I had built the archive, and then I started to find other articles and other Armatron stuff - I thought I had it all, but I didn't!).

Good luck!


Here they are, servos ...

Hitec Robot Servos:

The steering does appear to be servo driven, the problem being that the outer case of the rolling platform is sealed.. epoxied or whatever, no screws to take it apart. However, when the front wheels are steered or turned, there is definitely a gear train of some sort involved- so that would indicate a servo to me, without digging into much further. The RC car has been purchased as a toy to be explored in more detail the next time I'm laid up and need something to occupy me... that will probably put it on the chopping block somewhere before the end of the month- though I'm setting up and planning for a Halloween setup for the yard as this month's main useless timewaster. All in good time.

I mastered several games and a MMORPG before during my down times.. it is infinitely more fun to MAKE evil little robots than it is to blow up virtual ones...

By the way Applesauce- I like the way you think. Most here set out to build an obstacle AVOIDING bot, your plan for the exact opposite, a bot that seeks out the walls and bashes into them-- great stuff. You may want to consider mounting a Dremel or small drywall-destroying ablative armor. If you build them cheaply enough, you could just have em explode on impact, eventually cutting their way through any defenses. Really good first step in the whole "Crushing all resistance beneath my iron jackboots" phase. I do expect dominion over, say, Hawaii or maybe New Zealand in exchange for the helpful input, you understand...

I've wondered about using biological rather than mechanical- but a laser-equipped hamster isn't as reliable as you might think. That isn't to say that a laser-guide cannon that fires hamsters as ammo might not be an impossible (if messy) idea... and also found out that one right we Americans hold very dear, the Right to Bear Arms, isn't all that useful, unless you want to catch salmon. No opposable thumbs and always shedding. Just one of those things that sounds great on paper I guess.

If you're close enough to civilization, Craigslist isn't a bad option for picking up a lot of misc servos. It seems like there is always someone on there trying to undo their years of RC pack-ratting for a few bucks.