servo demolition
Archiver
Posts: 46,084
Hi there,
Last week, I wacked a few brand new servo's with a very nasty software bug.
It's pretty incredible, and expensive :-) I swapped a word with a byte
variable ( -> overflow in a FOR-loop) and instead of sending 1ms pulses, I
send 0.2 ms pulses to the unmod servos. The servo just turned fully
clockwise (360+ degrees!). All gears are broken and so is the pot probably.
Engineers from Robbe (=servo manufactors) understood my problem, but
explained that there are no safety stops or anything at all to prevent this.
is there any commonly used servo-safety method in "stamp land" that I am
unaware of?
thanks in advance,
happy stamping,
Matthijs Boerlage
Last week, I wacked a few brand new servo's with a very nasty software bug.
It's pretty incredible, and expensive :-) I swapped a word with a byte
variable ( -> overflow in a FOR-loop) and instead of sending 1ms pulses, I
send 0.2 ms pulses to the unmod servos. The servo just turned fully
clockwise (360+ degrees!). All gears are broken and so is the pot probably.
Engineers from Robbe (=servo manufactors) understood my problem, but
explained that there are no safety stops or anything at all to prevent this.
is there any commonly used servo-safety method in "stamp land" that I am
unaware of?
thanks in advance,
happy stamping,
Matthijs Boerlage
Comments
gears for the servos. Stripping out gears is quite common in the RC hobby,
especially after a crash, or other kinds of errors. It is doubtful the pot's
were damaged, as the output gears strip out before you could do anything to
hurt the pots.
I don't know about safety with servos. It's pretty much wide open there.
It's up to you.
But if you had used a serial input servo controller module, then it would
have helped to protect you, as you can't send a really bad command to the
servos with it in place. http://www.lynxmotion.com/ has a 8 and a 12 channel
servo controllers, other companies make them too. You could make one too, by
using a MCU and a bunch of servo connectors, for as many I/O pins as you
need. It is actually pretty good as basically it offloads the servo control
from your main CPU to the servo controller's CPU freeing up your main CPU
for other things.
Original Message
From: Boerlage, M.L.G. [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=sAZgr4cuUa0rh1EQWgRe4Ox7RihRj5vONFkIQksqpQQpjEoCeYOFxT-PzQxMCu3HtxYq5nPAsB5WBScw-TIqdDcMX5PliLk]M.L.G.Boerlage@s...[/url
Sent: Monday, January 21, 2002 5:46 AM
To: 'basicstamps@yahoogroups.com'
Subject: [noparse][[/noparse]basicstamps] servo demolition
Hi there,
Last week, I wacked a few brand new servo's with a very nasty software bug.
It's pretty incredible, and expensive :-) I swapped a word with a byte
variable ( -> overflow in a FOR-loop) and instead of sending 1ms pulses, I
send 0.2 ms pulses to the unmod servos. The servo just turned fully
clockwise (360+ degrees!). All gears are broken and so is the pot probably.
Engineers from Robbe (=servo manufactors) understood my problem, but
explained that there are no safety stops or anything at all to prevent this.
is there any commonly used servo-safety method in "stamp land" that I am
unaware of?
thanks in advance,
happy stamping,
Matthijs Boerlage
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/