Let's Make Robots!


Surveys small stones and rocks

This is my current robot study. TETUBO surveys small stones and rocks. The stones or rocks are picked up with a simple gripper mechanism. The rock sample falls in a kind of oversized test tube. In the moment only the radioactivity of the sample will be measured but many other sensors are possible. When the survey is finished the hatch on the other end of the test tube opens and the sample drops out.




Found simple possibilities to add other sensors ---

a) Metal detector to check if the rock sample has metallic inclusions. The detector coil is directly wound around the test tube:

b) Hall effect sensor to check if the rock sample is magnetic.


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I was trying to fiqure a way to make a servo powered gripper. The one your robot uses is perfect. great job! However what is the number of teeth your gears are?

Consider that the number of teeth on the gears does not matter. Since they are two of the same gear, the ratio is 1:1.

I am curious to find out if that coil setup might pick up external noise. To an extend where it would no longer serve as a (sensitive) detector.

Hi Rik,

My plan for the metal detector is quite simple as the sensivity need to be not very high (the rock sample drop through the coil). I also don't have a ground effect so I will not need a Faraday shield. I will build a simple LC oscillator with a 555. When a piece of metal is brought close to the coil, the output frequency changes.The output frequency will be measured by a connected Picaxe 08 by the count command.



Hmm, seems that Parallax use Tamiya parts. except for the side plates it's just a Tamiya tread kit. Presumably Parallax did a deal with Tamiya.

That's an interesting track configuration. It looks like you could have used the horizontal bar that is lying on top of the track as a track tensioner by making it's position adjustable up/down a cm or so. Maybe it is unnecessary for your robot. I mention it because I have never seen the tracks configured that way and it would make for simple adjustments if someone needed to.

Anyway, very cool robot. Can't wait to see a video.

Hi Ignoblegnome,

It's actually a Parallax Boe-Bot Robot Tank Tread Kit and a bad design (I can not remember why I bought it :)).  I adjusted the position (height) of the track drive wheel, but the tracks always jumped out at the smallest friction, so I added two castors. Now it works fine even on rough surface.

I like the simple, efficient design of this robot. Well done again Markus!

Sergey Korolyov once said: "The genius of a construction lies in its simplicity. Everybody can build complicated things". There is something true on it, I think, and I am trying to follow it :)

Nice structure, looks very nice ;-)