Let's Make Robots!

Version 2 of the newby robot..

Hi Group:


Am absoultly new to this, and fully intend to build the first version of the robot on these pages... However I really like the "Cup grabber" version ... Could someone here tell me how the heck one gets the arms to bend over to grab the cups? I buying parts for version one, BUT am also buying parts for version 2 as they are pretty much the same thing... TIA ... John ... Butler, WI USA.

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well, Frits is using servo motors for moving its hands. These motors are very popular among robot builders. There are two types of servo motors: continuous ones and angular (standard) ones. Continuous motors are usually used for driving wheels and this is not our case, so we have to deal with angular servos.

Angular servos are actually motors that move to an angle you tell them. So in the cup grabber motor, Frits is actually telling the robot's servo to move to a precise angle so that the arms can move and grab the cup.If I well remember those arms are doing two things: the bend down, and then they grab the cup. So to build a similar bot you would need more than one servo (one for turning or bending the arms down, and another one or maybe two to grab the cup). Anyways you may notice them in the video, they are rectangular boxes with three wires sticking out of them. 

 If you have also looked at the yellow drum machine (just an example of many) you should have noticed that it has a moving "head" which rotates from left to right. That thing that rotates is actually a servo.

 How to control servos? Well if you are using picaxe you just need to write:

servo x,pulse         where x is the pin the servo is attached to (output pin) and pulse is the lenght of the pulse you are sending to the servo motor. sending him a pulse of 125 (example) will make it turn to a precise angle, sending a pulse of 200 will make it rotate to another angle, and so on... (the usually have a range of 180° degrees)

For more detailed information you could check this link: http://www.seattlerobotics.org/guide/servos.html

Very well, captain! :)

Just 2 notes; A quite special thing about the Yellow Drum Machine(s) is actually that they do NOT use servos. But you are right that it would be the normal thing!

I am not sure about the questions on the Cuplifter.. I have just edited the post because I realized there was a dead link in there.. However, there are like a million pictures of that robot here:


- It should be possible to see how things are made, specially if you compare with its precender: http://letsmakerobots.com/node/254