I'm a theatre and show technitian, you're absolutely right that movement can
be to fast ;-)
What I meant is only, that it is not the servo's job to limit the speed. The
program should limit the speed like yours does, or a library can have a
slow-down adjustment.
I did not even look at the servo lib(s) yet, but I have an idea why Matt did
initialize the servos. When you're starting to transmit data to the servos, you
need to give them a position. A probably better, but more complicated way would
be just NOT to transmit anything to a servo which has not been assigned a
position yet. That way, the servo would usually just do not move, until it
receives the first position data.
Greets,Kiste
Am Montag, 17. Januar 2022, 19:25:56 MEZ hat hans
<[email protected]> Folgendes geschrieben:
Thank you DOOS, once I have a working program that does what I want for me, I
usually don't have the courage or the will to optimize it further. I will
definitely apply your recommendation.
That Matt's LIB contains the commands of the basic servo positions is difficult
as I mentioned.
You can disagree about the speed of the servos. When I use them in my dolls
without speed reduction, the movements are much too wooden.
Op maandag 17 januari 2022 om 13:49:51 UTC+1 schreef Kiste:
Hi hans,
heel mooie video's :-)
Your program fragment can be optimized a little, with no loss of function but
saving code and data space and also execution time (which is not so important,
as the purpose is to delay...)
tell=0for 4 loop [...] servo_move((old_pos[tell] + 1),tell+1) [...]
tell=tell+1
end loop
This can be done like
--tell=0for 4 using tell loop [...] servo_move((old_pos[tell] + 1),tell+1)
[...]-- tell=tell+1end loop
This way an invisible loop variable is omitted. In that special case, there's
another way to improve:
tell=0for 4 loop tell=tell+1 [...] servo_move((old_pos[tell] + 1),tell)
[...]end loop
Now, "tell" is always one count ahead. In each servo_move call, you're saving
the "+1", which takes code and possibly data space. So, why didn't I just state
"tell=1" and leave the increment at the bottom of the loop? Very curious PIC
assembler details... Setting a variable to zero is cheaper than setting to any
other number. The increment is done four times anyway, so there's no extra cost
to move it. What about combining both optimizations, like "for 4 using counter
loop; tell=counter+1 ;[...]"? Terrible. Incrementing a byte "tell=tell+1" is a
single assembler instruction. "tell=counter+1" is quite a complex calculation
which takes code and data space.
</smartassing>
The purpose of a servo is to move to a certain angle as fast as possible. How
fast, depends on the power of the servo and to the mass (or rotational inertia)
connected to it. It is not the responsibility of a library to slow the movement
down, although I think such functions wouldn't hurt as an extra.
Unfortunately, the communication to the servo is one-way, so, when switching
on, the controller can not know in which position the servos are. Thus, IMHO, a
library shoudn't move to any "initialisation position" on it's own. It's the
responsibility of the application program to move to a starting position. There
may be a certain procedure that works from all possible starting positions,
like e.g.
1. bend elbows2. wait for elbows are bent3. move shoulders outward4. ...
That example is clearly wrong for the linked video, as when shoulders are up
and inward, bending elbows might have the hands collide. But there might be
another order, which works from any starting position.
Greets,Kiste
(Jij kunt me ook "Doos" noemen :-)
Am Montag, 17. Januar 2022, 12:43:56 MEZ hat hans <[email protected]>
Folgendes geschrieben:
Here is a program part which i use for reduce 4 servo's speed
:,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,-- basic
position all servo's
servo_move(124,1)
servo_move(124,2)
servo_move(129,3)
servo_move(121,4)
---------------------------------------------------
var byte old_pos[4] = {124,124,129,121} -- start up beiden in centrum
var byte new_pos[4]
var byte tell =0
-----------------------------------------------------
---------------------------------------------------
procedure set_servo_pack (byte in x) is
var byte flag = 0
var byte tell = 0
while flag < 4 loop
flag = 0
tell = 0
for 4 loop
if old_pos[tell] < new_pos[tell] then
servo_move((old_pos[tell] + 1),tell+1)
old_pos[tell] = old_pos[tell] + 1
delay_1mS(x)
end if
if old_pos[tell] > new_pos[tell] then
servo_move((old_pos[tell] - 1),tell+1)
old_pos[tell] = old_pos[tell] - 1
delay_1mS(x)
end if
if old_pos[tell] == new_pos[tell] then
flag = flag + 1
end if
tell = tell +1
end loop
end loop
end procedure
Op zondag 16 januari 2022 om 19:40:07 UTC+1 schreef vasile:
Impressive! Congrats Hans!Perhaps using an encoder to "see" the servo position?
The less expensive it's a japanese amazing potmeter which can be rolled over (
360 degree movement, 270 degree cursor). I've used such devices, no failure...
On Sun, Jan 16, 2022 at 4:05 PM hans <[email protected]> wrote:
I've been using Matt's servo lib for years. The maximumnumber of servos in one
project was 12.( see https://youtu.be/ujfMYD5zXNU)
The only problem Ihad with the lib was that it resets the servos itself int a
fixed basicposition and that can conflict with the initial position in the
program. Sowhen you start up, you get a different base position for a while and
that cancause damage.
A second thing for me is the speed of movement from oneposition to another. I
now do this in a procedure within the program.
If this sometimes doesn't work out, I'll take another pic,even the small 12F683
works perfectly.
regards
Hans
Op zondag 16 januari 2022 om 10:35:02 UTC+1 schreef [email protected]:
Hello all,
I sometimes see projects using servo's using the JAL servo llibraries. I have
not yet used any servo's but I regularly have a project with LEDs that uses PWM
(like the servo library).
The number of PWM channels is limited on a PIC and it may be that the timers on
the PIC are needed for something else.
A solution would be to use a PCA9685. There are modules available to control up
to 16 servo's (or LEDs) using this module.
I was wondering if there are JAL users that have plans to use this device. If
so I might make a library for it in some near future.
Thanks.
Kind regards,
Rob
--
You received this message because you are subscribed to the Google Groups
"jallib" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/jallib/5cded4d9-1760-45a0-a8b0-d1f79718afaan%40googlegroups.com.
--
You received this message because you are subscribed to the Google Groups
"jallib" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/jallib/c72da766-937f-4e05-9971-7f50f2ac858fn%40googlegroups.com.
--
You received this message because you are subscribed to the Google Groups
"jallib" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/jallib/bae15549-0e90-45f7-a3e5-76442463f6edn%40googlegroups.com.
--
You received this message because you are subscribed to the Google Groups
"jallib" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/jallib/1247570722.650924.1642453335191%40mail.yahoo.com.
