Cheap Ball Casters for Small Robots

Hello everyone! :) In the title of this blog I mention that it is also about robotics. However, and to be honest, I've realized that I haven't posted much stuff about it. I hope to fix that in the following posts since recently I've finally finished some robot projects that I have been doing in the past months. Unfortunately I can't publish them yet. Maybe in a month or two :) Anyway, I'll start with a simple post regarding a simple but very useful part for small robots: ball casters!
You can buy ball casters from several robotics shops online and they're not the most expensive thing on earth. However, there are other options that can be cheaper and will save you from the waiting until you receive the ball casters that you may order from shops online. Some of the options fit in the spirit of Green Robotics, which is the idea of reusing and recycling everyday things to make robots. I'm going to show you three options that may suit your needs :) .

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I'll start with the option that I think to be the best of the three that I'm going to talk about. See the shiny metal balls stuck in a white plastic piece? They look really good, don't they? :)
Well, you can get them from massage gloves like the ones below:

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Each glove has 9 ball casters and is really cheap. The glove in the picture cost me 4€, leading to the price of 0.44€ for each ball caster, which is amazingly cheap :) . If you can't find these gloves in shops near you I think you can also find them on ebay. I must thank the user "dropes" from the Portuguese robotics forum Lusorob√≥tica who shared his finding when I asked for suggestions for ball casters some time ago. Thanks! :)
I have already used these kind of ball casters in five robots and they work great! :) The only bad thing about this ball casters is that you have to glue them to your robot structure since they have no mounting holes.
The next option is already known to lots of people and although it's not as good as the first option, tit can be used for simple robots too. It consists in using the roller ball from empty deodorant bottles:

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Since they're very lightweight and soft they will occasionally slide instead of rolling but that's not a big issue. They have more or less twice the size of the first ones.
The third and last option is to steal your girlfriend's/sister's lip gloss, (buy some lip gloss in some cheap chinese store for 0.7€) and remove the small ball caster from the top. It is very similar to the last one but is smaller.

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By the way, you'll have to spend some time cleaning it up since lip gloss is really, really sticky icky icky. Maybe leaving it in water with soap for some time will remove the lip gloss from the ball roller.
By the way, here's a curious thing... once you remove the ball roller from the small container it is exactly equal to this one, sold by pololu:

I guess they just buy them from the same factory that produces them for small lip gloss containers :)
So, now that you've seen three cheap options to use as a ball caster for your robot, start looking around and gather some for your future robots :) Below you can see some more pics of the three types of casters. Take care! :)

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