Let's Make Robots!

DAGU robot arm with object Tracking

Tracks moving objects

Robot Arm with Object tracking Sensor. The IR eye is used as an Object detection and tracking sensor. For more details about the eye see: http://letsmakerobots.com/node/11293. The robot arm will try to keep the distance between the sensor and the object fixed. Based on the data received from the four IR sensors the controller will decide the suitable position of the servo motors to keep the distance between the sensor and the object fixed. The controller used for this project is the Wild thumper controller board. for more details about the controller see: http://letsmakerobots.com/node/24368.

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if it is required to set accurate position of the robot arm then the Grip length must be calculated in term of grip width. The Grip used in this arm is from DAGU.The grip mechanism uses a scissor action to open and close the gripper, so the grip length changes depending on the grip width. The relationship of length to width was determined to be a third order polynomial( see http://letsmakerobots.com/node/24441):

y = -0.0181x3 + 0.0557x2 - 0.2001x + 10.64  

where, y; is the Grip length and x is the grip width

Phase #1 of this project is to build the required software that guide the robot arm to specified position in 3-D space. this software will depend on inverse kinematic  equations to estimate the joints angles. then, a lookup table will be used to find the required servos pulse widths.


I got the new controller last week. however i could not install the software in the CD. it is not working neither in my laptop with windows vista) nor in my desktop( with windows XP sp2). when i tried direct commands it works fine,  so i wrote my own software in VB script running on excel sheet.

the overall current drawn is higher than before and the servo speed is very high.


@oddbot:How much does this arm costs ?

:in my best australian accent:

Well mate, I don't think OB sets pricing for his goods, but here's a spiffy place you can buy a DAGU arm to throw in your boot...


The arm is not even my design. DAGU were producing it before I arrived here.

the arm in horizontal position. the current is increased due to arm weight.

the arm in horizontal position. the current is increased largely because the lower servo must move to the other end but it could not do that because the servo power  could not counter the arm weight.

The original servos for this kit were 6V servos. Recently we changed the servos to a better quality model. Unfortunately they are 7.2V servos. I am told the new controller was sent about 3 days ago.

ok... i will wait for the new controller and recheck the currents. i expect to receive it next Sunday.