can we contro a dc motor with bs2 like our servomotor
rakeshakurathi
Posts: 30
hi,
can we control a dc motor with bs2 like our servo motor ...
for controlling a servo we will give commands like pulsout is there any command to cantrola dc motor
waht is the deff between a servo and dc why cant we move dc using a pulsout actually what does pulsout exactly mean
what makes dc motor to move is not pulses plss explain
can we control a dc motor with bs2 like our servo motor ...
for controlling a servo we will give commands like pulsout is there any command to cantrola dc motor
waht is the deff between a servo and dc why cant we move dc using a pulsout actually what does pulsout exactly mean
what makes dc motor to move is not pulses plss explain
Comments
more complex...
A pulse is a series of highs (on) and lows (off) that work with the circuits built into a servo. They tell the servo to move
X amount of distance and then hold that position. Modified servos for rotation (like those supplied with the boebot kit)
are altered so they no longer go to a location and hold it, instead they rotate a lot like a normal motor... they still
need pulses to trigger rotation though.
Its helpful to think of pulses as morse code for electronics.
A motor works by providing a constant flow of power in one direction. If you reverse it, the motor will go in the other
direction (although not all motors can be reversed).
Unfortunately, you can't just hook a motor up to a pin and set it to HIGH. This will draw too many amps through the
BS2 and fry it.
Also you've got the problem of when the motor slows or stops. I think its called inductance... the motor suddenly becomes
a generator when you cut the power, and that too can fry the BS2.
You need a way to isolate the motor from the BS2, a way to do this is called a relay.
A relay takes a small, low-voltage signal (like the 5 volt from the BS2 pins) and turns on a higher voltage signtal... exactly
like a switch.
Since its isolated, and the only power going to the motor is from another source (from another battery, for example... I'm
not sure but I think VIN will work too... better ask someone who knows more before trying it though) then there's no chance
of damaging the bs2.
The only problem with a relay, is it can only power the motor going in one direction. There's a solution for that called the
H-bridge. The H-bridge is basicly several relays tied together to help reverse the power when needed.
I believe Parallax sells a nice H-bridge, and there are several others out there for very reasonable prices (I can give you
some part numbers and such if you need them... including one I've used personally).
Anyways... I'm pretty much a total newbie. I just read a lot and do a lot of research... take my advice at your own risk [noparse]:)[/noparse]
thank u for u r advice ! i have some basic doubts
can i use any relay for my basic stamp or is there any specification to be used !!!!
and can u pls specify me the diagram of H-bridge
As far as the H-bridge... most of the time they are self-contained intergrated circuits (ICs/Chips) that
handle most everything for you.
Parallax sells a seriously powerful and safe one for $49.95 with a ton of stuff built into it for safety.
http://www.parallax.com/Store/Accessories/MotorServoControllers/tabid/160/CategoryID/35/List/0/Level/a/ProductID/64/Default.aspx?SortField=ProductName,ProductName
They also sell another Motor Controller that looks pretty nice for $23.95
http://www.parallax.com/Store/Accessories/MotorServoControllers/tabid/160/CategoryID/35/List/0/Level/a/ProductID/491/Default.aspx?SortField=ProductName,ProductName
There are also some third-party H-bridge chips that are commonly used, but they don't have as simple of an interface,
take more pins and they don't have all the safeties built in.
Technic-R-C
Technic-R-C