Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: ltmhall on October 06, 2006, 10:08:11 AM

Title: need servo and vbasic stamp help ?
Post by: ltmhall on October 06, 2006, 10:08:11 AM
Iím Building an autonomous mobile robot using differential drive and have a few questions. Iím using two Hitec 422 servo motors, a Basic Stamp II (education board), two Dubro 2.75 in. wheels, and a NARP 4cm omni direction wheel.

1)† †If Iím using two HS 422 servo motors and a Basic Stamp II do I need an H-bridge. I was planning on connecting my servo motors to an L293 chip then connecting the L293 to a Basic Stamp, but a classmate told me I didnít need one, I could connect the servos straight to the Basic Stamp. Please Help!

2)† †If I need to connect my servos to an H-bridge do I actually open my modified servos and connect the two pins of the motor to the H-bridge.

3)† †I read a regular caster is a very great ideal for the third wheel, does anyone know a good way to mount an omni directional wheel to an aluminum chassis.
Title: Re: need servo and vbasic stamp help ?
Post by: Admin on October 06, 2006, 11:46:33 AM
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If Iím using two HS 422 servo motors and a Basic Stamp II do I need an H-bridge. I was planning on connecting my servo motors to an L293 chip then connecting the L293 to a Basic Stamp, but a classmate told me I didnít need one, I could connect the servos straight to the Basic Stamp.

Servos have their own built in circuitry, which is why I highly recommend them. Your classmate is right, no H-bridge required. Just give the servo between 4 and 6 volts power, and a square wave signal to the signal line (which is where you connect the stamp to), and thats it!

Quote
I read a regular caster is a very great ideal for the third wheel, does anyone know a good way to mount an omni directional wheel to an aluminum chassis.

For the omniwheel castor, there are many ways to attach it. One would be get a long rod, put the omniwheel in the center, then bend the rod into a U shape. Then attach the two ends of the U to the robot chassis.