Subject:
|
Re: power and servo
|
Newsgroups:
|
lugnet.robotics.handyboard
|
Date:
|
Thu, 16 Jan 1997 18:04:35 GMT
|
Original-From:
|
Fred G. Martin <FREDM@MEDIA.ihatespamMIT.EDU>
|
Viewed:
|
2199 times
|
| |
|
|
[problem 1: voltage on motor chips when no motor voltage applied]
This is normal, because the motor chip INPUTS have +5v signals on
them. These signals "bleed" into the motor chip power supplies.
This isn't dangerous, but it isn't particularly good either. You
shouldn't turn on the board when the motor battery isn't connected.
> 1) I cut the trace connecting the the motors to the main board supply, so
> that I could power them independently (as per the instructions I found on
> the web). The board works fine as long as a battery is plugged into the
> motor power header (in addition to the 9V system battery). However, I've
> noticed that if I unplug the batteries from the motor power supply, and
> take a voltage reading off the motor header, I get a reading of 2-4V.
> Correct me if I'm wrong, but this doesn't seem like a good thing! I've
> checked the trace to ensure it is fully cut (and the right one :-) ), but
> I can't figure out where this voltage is coming from. Does anyone know
> what's wrong?
[problem 2: servo not working]
You aren't hooking it up right. The servo ground lead goes to the
motor ground, NOT a motor output. The motor ground is the two pins
labelled "-" where you plugged in the external motor battery.
The servo power lead goes to a +5v source.
You don't use the "fd(0)" command to turn on the servo; you use the
init routine that's part of the servo_a5.icb package, and set the
servo position global variable.
> 2) I recently hooked up a servomotor to my handyboard. Its signal input
> is plugged into pin TOC3 ( or TCO3?), and power/ground is plugged into
> one of the motor outputs. I turned on the motor (fd(0);) and loaded the
> servo_a5.icb routine I found on the HandyBoard site. Unfortunately, the
> motor didn't respond to the init command (or any other one). I then
> hooked an oscilloscope up to the signal pin, to see the output waveform.
> What I saw looked like a DC offset triangular wave. This didn't change,
> no matter what command I issued. I also tried hooking the servo into
> Digital port 9 and loading servo_a7.icb with the same result (except the
> waveform was different). I'm using the latest beta version of IC (3.10?).
> Is there something I can do to find out if it's the port or the SW?
>
> Sorry to be so verbose, but I figured the more info. I give, the easier
> it will be to diagnose. Thanks in advance for your help.
> Jeff
>
>
-Fred
|
|
Message is in Reply To:
 | | power and servo
|
| Hi everyone, I've got two problems that I hope your combined expertise can solve. 1) I cut the trace connecting the the motors to the main board supply, so that I could power them independently (as per the instructions I found on the web). The board (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
|
2 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
