ESC Problem Again...

Archiver

Hmm, I still can't figure this one out. I did this:

For x = 1 to 10000
pulsout 3, x

and I still didn't get a response from the motors???

I thought this ESC only needed GND, 5V+, and Signal. After sweepng the
signal range, it does not look to promising. Does anyone else have any
ideas?

Karl
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Archiver

Just looking at this code fragment, I'd say you need a PAUSE in
there. Otherwise it will step thru from 1 to 10000 very quickly, and
you may never see the motor move. Most ESCs have pots in them so
that you can do neutral and endpoint adjustments. Have you found
where these points are in the PULSEOUT range? Another way to check
would be to plug a servo into the channel and get it to go from far
right to center and then left. Once that is working, try plugging
the ESC back in and see if it works the same. Do you have an RC
receiver to check that the ESC is working properly absent the Stamp?

Kevin

--- In basicstamps@y..., "Arch- Angel" <sefiroth@h...> wrote:
> Hmm, I still can't figure this one out. I did this:
>
> For x = 1 to 10000
> pulsout 3, x
>
> and I still didn't get a response from the motors???
>
> I thought this ESC only needed GND, 5V+, and Signal. After sweepng
the
> signal range, it does not look to promising. Does anyone else have
any
> ideas?
>
> Karl
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com

Archiver

Have you got x set up as a word or a byte? It must be a word to have a value
over 255.

---

Original Message

---

> Hmm, I still can't figure this one out. I did this:
>
> For x = 1 to 10000
> pulsout 3, x
>
> and I still didn't get a response from the motors???
>
> I thought this ESC only needed GND, 5V+, and Signal. After sweepng the
> signal range, it does not look to promising. Does anyone else have any
> ideas?

Archiver

--- In basicstamps@y..., "Arch- Angel" <sefiroth@h...> wrote:
> Hmm, I still can't figure this one out. I did this:
>
> For x = 1 to 10000
> pulsout 3, x
>
> and I still didn't get a response from the motors???
>
> I thought this ESC only needed GND, 5V+, and Signal. After sweepng
the
> signal range, it does not look to promising. Does anyone else have
any
> ideas?
RC servos and ESCs (which simulate servos) need a very specific
output pulse shape to work. You can't just blast a string of pulses
at them and expect to see anything happen. First, the pulse must
typically be in the range of .5 to 1.5 milliseconds duration (some
servos may vary from this value a bit), which represent the low and
high range of position (speed, in the case of an ESC). 1.0 ms is
generally neutral. Second, the pulses must be repeated at a specific
frequency, which I believe means about a 15 to 20 ms pause between
pulses. So basically you need something that looks like this:

loop:
pulseout 3,x 'where x is the value which gives the right
'length pulse on your stamp - varies by stamp type
pause y 'where y is a value that corresponds to the
'required delay between pulses in ms, perhaps 20
goto loop

This is very hard to do on a stamp and still do any other work at the
same time. It's especially hard to get a consistent time between
pulses when a lot of other code is being executed. That's why they
sell dedicated servo controllers that can generate these pulses
continuously from a single command. Check the documentation to get
the right values for x and y, but I believe for a BS2 x can vary from
about 250 to 750 and y is about 20.

Chuck

Archiver

Here is a simple code snippet that works with a BS2SX and a Futaba 148
servo:

Pulse VAR WORD
Servo_Port CON 3

'unremark whichever line you want to use. I would start with the pulse at
1550
'so the servo will be approximately mid-travel. Keep in mind these values
vary
'depending on which Stamp you use due to the length of the counts used to
'generate the pulses.

'Pulse = 400 'position servo at 0 degrees (minimum travel)
Pulse = 1550 'position servo at 90 degrees (center of travel)
'Pulse = 2700 'position servo at 180 degrees (maximum travel)

Loop:

PULSOUT Servo_Port,Pulse
PAUSE 20

GOTO Loop

---

Original Message

---

From: "Chuck Davis" <cdavis@o...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, May 10, 2001 3:27 PM
Subject: [noparse][[/noparse]basicstamps] Re: ESC Problem Again...


> --- In basicstamps@y..., "Arch- Angel" <sefiroth@h...> wrote:
> > Hmm, I still can't figure this one out. I did this:
> >
> > For x = 1 to 10000
> > pulsout 3, x
> >
> > and I still didn't get a response from the motors???
> >
> > I thought this ESC only needed GND, 5V+, and Signal. After sweepng
> the
> > signal range, it does not look to promising. Does anyone else have
> any
> > ideas?
> RC servos and ESCs (which simulate servos) need a very specific
> output pulse shape to work. You can't just blast a string of pulses
> at them and expect to see anything happen. First, the pulse must
> typically be in the range of .5 to 1.5 milliseconds duration (some
> servos may vary from this value a bit), which represent the low and
> high range of position (speed, in the case of an ESC). 1.0 ms is
> generally neutral. Second, the pulses must be repeated at a specific
> frequency, which I believe means about a 15 to 20 ms pause between
> pulses. So basically you need something that looks like this:
>
> loop:
> pulseout 3,x 'where x is the value which gives the right
> 'length pulse on your stamp - varies by stamp type
> pause y 'where y is a value that corresponds to the
> 'required delay between pulses in ms, perhaps 20
> goto loop
>
> This is very hard to do on a stamp and still do any other work at the
> same time. It's especially hard to get a consistent time between
> pulses when a lot of other code is being executed. That's why they
> sell dedicated servo controllers that can generate these pulses
> continuously from a single command. Check the documentation to get
> the right values for x and y, but I believe for a BS2 x can vary from
> about 250 to 750 and y is about 20.
>
> Chuck
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>