Connecting an R/C servo motor on BS1
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I did not get a response to my first post on this - so hoping someone
will help me out here. It must be something simple. I use the following
code to swing a servo to three different positions. The motor always
swings to the first position, but then the next two never work. It just
sits and does a little hiccup of movement but immediately returns to the
first position.
I also get those "hardware not found" messages or "eprom verify failed"
but if I just punch the program down a few more time it takes. What is
this? Doesn't appear to be a loose eprom.
Thanks in advance for any suggestions.
Theron Wierenga, Muskegon, MI
Symbol i = b10
Symbol j = w4
dirs = %11111111
loop: for j = 1 to 50
pulsout 0,100 ' 150 to center
pause 20
next
for j = 1 to 50
pulsout 0,150
pause 20
next
for j = 1 to 50
pulsout 0,200
next
goto loop
will help me out here. It must be something simple. I use the following
code to swing a servo to three different positions. The motor always
swings to the first position, but then the next two never work. It just
sits and does a little hiccup of movement but immediately returns to the
first position.
I also get those "hardware not found" messages or "eprom verify failed"
but if I just punch the program down a few more time it takes. What is
this? Doesn't appear to be a loose eprom.
Thanks in advance for any suggestions.
Theron Wierenga, Muskegon, MI
Symbol i = b10
Symbol j = w4
dirs = %11111111
loop: for j = 1 to 50
pulsout 0,100 ' 150 to center
pause 20
next
for j = 1 to 50
pulsout 0,150
pause 20
next
for j = 1 to 50
pulsout 0,200
next
goto loop
Comments
> but if I just punch the program down a few more time it takes. What is
> this? Doesn't appear to be a loose eprom.
>
Don't know, but if you are using a battery, is its output voltage OK?
> Symbol i = b10
> Symbol j = w4
>
> dirs = %11111111
>
> loop: for j = 1 to 50
> pulsout 0,100 ' 150 to center
> pause 20
> next
> for j = 1 to 50
> pulsout 0,150
> pause 20
> next
> for j = 1 to 50
> pulsout 0,200
> next
> goto loop
The code looks OK except for the missing Pause in the 3rd loop. Again, how
is your battery or power supply? Most servos draw 300ma to 1 amp when
moving. If your power supply or battery is dropping in voltage when the
servo moves, the stamp may reset. You probably realize that the small 9V
battery does not provide enough current to run a servo. You should use a
separate power supply or larger battery to run the servo since the BS1
regulator can only source ~50ma. A 6 volt battery is OK for the servo, but
remember to connect the battery neg to the Stamp system gnd.
Hope this is useful,
Ray McArthur
Thanks for the answer, I took the extra pause out by accident when I
edited out my comments before sending the email. I thought about the 9v battery
also, and so I hooked up a 9 v 800ma wall wart. My digital voltmeter shows its
putting out about 11.6 volts because of the low load I suspect. No difference
with this supply. I wonder if it's the type of servo I have, it's a Futaba
FP-S14B, just something I bought at a hobby store to experiment with.
Regards, Theron
Ray McArthur wrote:
> > I also get those "hardware not found" messages or "eprom verify failed"
> > but if I just punch the program down a few more time it takes. What is
> > this? Doesn't appear to be a loose eprom.
> >
> Don't know, but if you are using a battery, is its output voltage OK?
>
> > Symbol i = b10
> > Symbol j = w4
> >
> > dirs = %11111111
> >
> > loop: for j = 1 to 50
> > pulsout 0,100 ' 150 to center
> > pause 20
> > next
> > for j = 1 to 50
> > pulsout 0,150
> > pause 20
> > next
> > for j = 1 to 50
> > pulsout 0,200
> > next
> > goto loop
>
> The code looks OK except for the missing Pause in the 3rd loop. Again, how
> is your battery or power supply? Most servos draw 300ma to 1 amp when
> moving. If your power supply or battery is dropping in voltage when the
> servo moves, the stamp may reset. You probably realize that the small 9V
> battery does not provide enough current to run a servo. You should use a
> separate power supply or larger battery to run the servo since the BS1
> regulator can only source ~50ma. A 6 volt battery is OK for the servo, but
> remember to connect the battery neg to the Stamp system gnd.
>
> Hope this is useful,
> Ray McArthur
Where are you getting the power for the red (power) lead for the servo? As
you may know, it cannot be powered off the BS1 +5 volts because of the
regulator limitations. Run this lead to a separate 5 or 6 volt power supply
or batteries, at least "C" size. I looked in my Tower catalog, but cannot
find a Futaba S14B ... there is an S148, which is a standard servo that
should work.
Ray McArthur
> Thanks for the answer, I took the extra pause out by accident when
I
> edited out my comments before sending the email. I thought about the 9v
battery
> also, and so I hooked up a 9 v 800ma wall wart. My digital voltmeter shows
its
> putting out about 11.6 volts because of the low load I suspect. No
difference
> with this supply. I wonder if it's the type of servo I have, it's a Futaba
> FP-S14B, just something I bought at a hobby store to experiment with.
Thank you for your reply, I'm at work right so I can't check until
tonight but I think you have just solved my problem. Yes, I was taking the
voltage from the BS1 board. I haven't done anything really dumb in a couple of
weeks so I guess I was due :-) I believe those little 5v regulators in the
transistor case shut down at something like 300 ma. Thanks for catching this.
Regards, Theron
Ray McArthur wrote:
> Theron, one more question:
>
> Where are you getting the power for the red (power) lead for the servo? As
> you may know, it cannot be powered off the BS1 +5 volts because of the
> regulator limitations. Run this lead to a separate 5 or 6 volt power supply
> or batteries, at least "C" size. I looked in my Tower catalog, but cannot
> find a Futaba S14B ... there is an S148, which is a standard servo that
> should work.
>
> Ray McArthur
>
> > Thanks for the answer, I took the extra pause out by accident when
> I
> > edited out my comments before sending the email. I thought about the 9v
> battery
> > also, and so I hooked up a 9 v 800ma wall wart. My digital voltmeter shows
> its
> > putting out about 11.6 volts because of the low load I suspect. No
> difference
> > with this supply. I wonder if it's the type of servo I have, it's a Futaba
> > FP-S14B, just something I bought at a hobby store to experiment with.
You caught it, separating the supplies did it. All works fine. Thanks.
Regards, Theron Wierenga
Ray McArthur wrote:
> Theron, one more question:
>
> Where are you getting the power for the red (power) lead for the servo? As
> you may know, it cannot be powered off the BS1 +5 volts because of the
> regulator limitations. Run this lead to a separate 5 or 6 volt power supply
> or batteries, at least "C" size. I looked in my Tower catalog, but cannot
> find a Futaba S14B ... there is an S148, which is a standard servo that
> should work.
>
> Ray McArthur
>
> > Thanks for the answer, I took the extra pause out by accident when
> I
> > edited out my comments before sending the email. I thought about the 9v
> battery
> > also, and so I hooked up a 9 v 800ma wall wart. My digital voltmeter shows
> its
> > putting out about 11.6 volts because of the low load I suspect. No
> difference
> > with this supply. I wonder if it's the type of servo I have, it's a Futaba
> > FP-S14B, just something I bought at a hobby store to experiment with.