Let's Make Robots!

What sensors make sense on a simple gripper arm?

I just purchased a dagu MkII gripper,  and am making a 5dof arm for it.  I do not have any experience whatsoever with operating a robotic arm/gripper.   What sensors make sense on this?   I know servo feedback for grip force, but does a gyro or accellerometer make sense?   I can visually see the full range of motion with the Raspberry Pi cam, but would feel better if there was some way to gaurantee "level".... 


I've searched this site, and cant find much other than pressure sensors or cameras on the grpper.





All I need is just one more toy...

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Some bots have a camera on their hand, so it could see what's it picking up.

It is able to see *almost* the whole range of motion of the arm. 



Sparkfun have released a new "Essential Sensor" kit that has a lot of good options such as a flex sensor.


An accelerometer is useful if you want to carry liquids without spilling them.

As the gripper is all metal you probably want to put some rubber on the grippers for traction. You can make a crude pressure sensor from the anti static foam you get IC's in. http://letsmakerobots.com/node/2684


I will look at both the rubber grip as well as the pressure sensor.



If you are always going to want the gripper to be level, connect from the arm to your gripper (instead of a servo just have a hinge with a connect from the arm to your gripper) so it will always be level.  Sorry, not explaining it very well.  


shows a picture of how to make the arm level.  Click on the starting video, and they show what I mean.  




There's a name for that mechanical arrangement.  Back hoes and Bull dozers use it to keep buckets and blades level.

I'm sure OddBot is banging his head right now saying "Why didn't you just buy a service droid?"


Oh well...  plugging on.


Thanks for the direction.


I figured there had to be a name for it.  Sorry for being so vague; it is hard to describe.

The SD is nice and a cool design (I bought one for my son for Christmas with a Rover 5).  But it is also fun to build something too.  On my present project, I have been using aluminum U channel ($10 for 8' section at HD) for the arms and small Lazy Susan bearings for the elbow, wrist etc.   You can cut aluminum on a tablesaw or chopsaw, it is light and strong and easy to drill holes into so it is relatively easy to work with.  Just an idea on what to do for arms with the gripper.  I will be posting over the next few weeks to show what I have built.

I am sure you will find something to do with the dagu gripper.  As always, I look forward to seeing what you come up with.



would be sufficient to know if/when the servo has stalled. Cheaper and easier(?) than adding more hardware. As for level, what about some kind of simple tilt sensor? If you are already reading the pot, you could probably avoid the tilt sensor and just have a homing routine for the servo at each start up. Maybe check if the gripper is open before rotating?