[PD] stepper message syntax (pd through arduino)

[Christian Klippel]

hi,

Am Montag, 2. Oktober 2006 16:39 schrieb ad:
> On Oct 2, 2006, at 3:16 PM, Martin Peach wrote:
> [...snip...]
>
> ok, but if one wants to do this by the way of, say an [hslider], if
> possible. How can i get to set/unset 4 messages..uhmm? what would be
> the right way to send those patterns to the arduino?
>

my idea would be the following:
if it cant do already, change the arduino firmware to accept a byte that gets 
send to a arduino port. usually, you need 4 bits for a stepper, depending on 
the type. so you can mask away the unused 4 bits, and set the port-lines at 
once directly. this will give you a much smoother operation of the stepper as 
well.

>
> >  The sequence can be found by trial and error. When it's wrong the
> > motor just jitters. It's not dangerous.
>
> yes, i ve seen that, it doesnt even go as hot as a servo does.
>

you can either have the stepper unpowered when not moving. this will save 
energy, avoiding to get hot driver stages. the drawback is that the motor 
doesnt hold its position anymore, when you apply some torque to it.
then you can leave the lines powered, to literally make the motor stick to the 
position. but this will cause a higher current draw, and may heat up the 
driver transistors.

also note that there is a way to control a stepper in half-steps as well, 
giving you twice the number of steps it usually has. it does so by hoding the 
rotor inbetween two positions.

regarding stepper motors, you may want to take a look at this link collection:
http://www.doc.ic.ac.uk/~ih/doc/stepper/

> tx again martin
> /a
>

greets,

chris

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