servo to basic stamp II help ?
I’m Building an autonomous mobile robot using differential drive and have a few questions. I’m using two continous rotation modified 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 I’m 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 didn’t 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.
ANY HELP WOULD BE APPRECIATED
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1) If I’m 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 didn’t 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.
ANY HELP WOULD BE APPRECIATED
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Comments
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- Stephen
2. You can drive the servo's with Vdd. Note each servo will pull around 100 mA when active. Also, the linear regulator will use up some current as heat while regulating. So you COULD directly connect a 6-volt battery to the 'red' wire of each servo and get direct 6 volt drive with no losses. If you do this, you MUST insure the 'ground' (Vss) wire for that battery is connected to the +5 volt ground.
to the ground on the board of education.
for each motor.
If you look at the physics -- the right wheel servo does have to be commanded to run in the opposite direction of the left wheel servo, in order to get both wheels rolling 'forward'. That's assuming you've mounted both servo's "back-to-back", the most common mounting scheme. But you command that IN THE CODE, not in the hardware.
There is no hardware way to tell a servo 'ok, you're the right servo, so you should REVERSE everything I tell you'. They're not that smart. But this is really not a major problem, and has been easily solved by a generation of 'modified-servo-robot-builders'.
Post Edited (ltmhall) : 10/12/2006 3:47:03 PM GMT
The idea of this is that you PULSOUT to your wheels, then do something else for 20 mSec, then repeat the PULSOUT. That way, you can have movement on a 'single-tasking' processor like the BS2.