How do the grippers in this robotic gripper open and close?

[MaltiK]

http://sketchup.google.com/3dwarehouse/details?mid=2e5fda1e83511108516989a2c1525167

Download link

http://sketchup.google.com/3dwarehouse/download?mid=2e5fda1e83511108516989a2c1525167&rtyp=s6&fn=pinza_robot&ctyp=other&ts=1202485797000


I mean how do the gears work, there is no automation/electricity?

[airman00]

its missing a part
theres a motor with a gear thats in between the two gears that turns them

[szhang]

I don't think it is missing a gear.

One of the two gears has to be actuated though (there needs to be a motor turning one of the big gears), in google sketchyphysics you can drag on the gear and turn it.

[airman00]

I don't think it is missing a gear.

One of the two gears has to be actuated though (there needs to be a motor turning one of the big gears), in google sketchyphysics you can drag on the gear and turn it.

well yea you can do that also , or add another gear to it , both would yield the same result  - as long as each fingers gripper is turning in the opposite direction you are fine.

[AdvsNoob]

I be leave you need a servo ^_^ never really made gripper, you might need two but there really not alot of money

[MaltiK]

I don't think it is missing a gear.

One of the two gears has to be actuated though (there needs to be a motor turning one of the big gears), in google sketchyphysics you can drag on the gear and turn it.

well yea you can do that also , or add another gear to it , both would yield the same result  - as long as each fingers gripper is turning in the opposite direction you are fine.

Do I need PWM motors to do the trick? I ask this because it seems I can just use a transistor to switch the direction of the motor if no Motor Chip is used. If I just used a regular DC motor underneath the gripper mechanism, connected to one gear? What I am asking is, is there an alternative to using a servo instead of using a motor with a motor driver chip?

[Ro-Bot-X]

The purpose of using a servo is that the servo can go to many positions while a DC motor (with driver) will go from full open to full close. However, if you attach a geared DC motor on one wheel and attach a potentiometer to the other wheel (and plug it in an analog pin of your microcontroller), you can move the motor until the pot reaches a certain position then put the motor on brakes (send same signal on both direction lines, like shorting the motor leads) to hold that position. This way you will simulate a servo.