Subject:
|
(no subject)
|
Newsgroups:
|
lugnet.robotics.handyboard
|
Date:
|
Thu, 21 Jan 1999 22:59:52 GMT
|
Original-From:
|
Max Davis <bendavis@mit.NOMORESPAMedu>
|
Viewed:
|
734 times
|
| |
|
|
Hello, folks.
My first foray back onto the list in a few years.
I checked the archives and didn't see an answer to this question,
so here goes:
Until recently, I taught a freshmen robotics seminar using old
6.270 boards, motors, and parts bought from past contestants.
Recently I got some money to move over to 6 new Handy Boards, as the
old 6.270 boards were unreliable (soldered in a hurry by students
learning to solder, etc..). In general the Handy Boards are great,
but I have one big problem:
The motor driver chips (the TI SN75 ones) burn out pretty easily
when I use the 6.270 motors. I don't know anything about the 6.270
motors except that they come from Polaroid, but maybe because they
were originally selected to run off of the 6-volt 6.270 board
batteries (and through the 1.6 amp 6.270 board motor drivers rather
than the 1 amp handyboard motor drivers), they draw too much current
with the 9-volt handyboard batteries?
I notice that the motor driver chips on the Handyboard are not heat
sinked in any way. Has anyone had experience heat sinking them?
Has anyone tried stacking TI SN75whatever chips to get a better
current rating? Do you think this would work?
Does anyone have suggestions for a good place to get other 9-volt
motors (and cheaper than the lego motors)?
I'd rather not go to some much more expensive motor driver like the
LMD18200 ($20 each, and a different pinout)... after buying the Handy
Boards I don't have too much money left.
thanks for any and all suggestions,
--
Max Davis
Experimental Studies Group, MIT
|
|
Message has 1 Reply:
 | | 6.270 vs. Handy Board motor stuff
|
| [Max Davis] spake unto the ether: (...) Too much current (and voltage) for those original Polaroid motors, which are 6-volt. (...) I heat-sink mine with the clip-on variety; it helps. (...) I have done the 6.270 piggyback hack with the motor driver (...) (26 years ago, 22-Jan-99, to lugnet.robotics.handyboard)
|
2 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
